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• 1.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
An electron energy loss spectrometer based streak camera for time resolved TEM measurements2017In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 176, p. 5-10Article in journal (Refereed)

We propose an experimental setup based on a streak camera approach inside an energy filter to measure time resolved properties of materials in the transmission electron microscope (TEM). In order to put in place the streak camera, a beam sweeper was built inside an energy filter. After exciting the TEM sample, the beam is swept across the CCD camera of the filter. We describe different parts of the setup at the example of a magnetic measurement. This setup is capable to acquire time resolved diffraction patterns, electron energy loss spectra (EELS) and images with total streaking times in the range between 100 ns and 10 μs.

• 2. Beckmann, M.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
How well do we know the circumference of a storage ring?2015In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 771, p. 115-120Article in journal (Refereed)

High precision nuclear physics experiments in storage rings require precise knowledge of the beam energy. In the absence of electron cooling, which provides this information, one can use the frequency of the radio frequency system in conjunction with knowledge of the circumference of the ring. We investigate to which precision the latter can be determined in the presence of magnet misalignment and orbit correction.

• 3. Bezshyyko, Oleg
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, High Energy Physics.
PETAG01: A Program for the Direct Simulation of a Pellet Target2008In: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 178, no 2, p. 144-155Article in journal (Refereed)

We describe a numerical model of an internal pellet target to study the beam dynamics in storage rings, where the nuclear experiments with such type of target are planned. In this model the Monte Carlo algorithm is applied to evaluate the particle coordinates and momentum deviation depending on time and parameters of the target. One has to mention that due to statistical character of the pellet distribution in the target the analytical techniques are not applicable. This is also true for the particle distribution in the stored beam, which is influenced by various effects (such as a cooling process, intra-beam scattering, betatron oscillation, space charge effect). In this case only the Monte Carlo technique to model energy straggling in combination with the pellet distribution in the target should be considered.

Program summary

Program title: PETAG01 Catalogue identifier: ADZV_v1_0

Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland

Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html

No. of lines in distributed program, including test data, etc.: 1068

No. of bytes in distributed program, including test data, etc.: 11314

Distribution format: tar.gz

Programming language: Fortran 77, C/C++

Computer: Platform independent

Operating system: MS Windows 95/2000/XP, Linux (Unix)

RAM: 128 MB Classification: 11.10

Nature of problem: Particle beam dynamics with use of the pellet target.

Solution method: Monte Carlo with analytical approximation.

Running time: dozens of seconds

• 4.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
ESS RF Source and Spoke Cavity Test Plan2015Report (Other academic)

This report describes the test plan for the first high power RF source, ESS prototype double spoke cavity and ESS prototype cryomodule at the FREIA Laboratory.

• 5.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
Precise measurements of hot S-parameters of superconducting cavities: Experimental setup and error analysisManuscript (preprint) (Other academic)

Superconducting accelerating cavities used in modern particle accelerators change their intrinsic properties when excited to very high field levels close to the critical field where the superconductivity is affected. In this report we describe a test-bench and data analysis procedure to determine the so-called hot S-parameters from strongly driven cavities and use them to quantify the properties of the cavity at varying field levels. The method is based on analysing reflection coefficient for a large number of configurations in a self-excited loop setup and determining the cavity coupling coefficient $\kappa=Q_0/Q_{ext}$ as a function of cavity voltage to high accuracy. Since $Q_{ext}$ is determined independently and is a constant, from the information of $\kappa$ the Q-slope can be determined.

• 6.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Minimization of power consumption during charging of superconducting accelerating cavities2015In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 801, p. 78-85Article in journal (Refereed)

The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Enemies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

• 7.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
The Momentum Distribution Of The Decelerated Drive Beam In Clic And The Two-Beam Test Stand At Ctf32014In: Proceedings of IPAC2014, Dresden, Germany., 2014, p. 62-64Conference paper (Other academic)
• 8.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Solid-state amplifier development at FREIA2014Conference paper (Refereed)
• 9.
CEA/DSM/IRFU Saclay, France.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Two Beam Test Stand Experiments in the CTF3 Facility2011Conference paper (Refereed)

The CLEX building in the CTF3 facility is the placewhere essential experiments are performed to validate theTwo-Beam Acceleration scheme upon which the CLICproject relies. The Drive Beam enters the CLEX hall afterbeing recombined in the Delay loop and the CombinerRing in intense beam trains of 24 A – 120 MeV lasting140 ns and bunched at 12 GHz, although other beamparameters are also accessible. This beam is thendecelerated in dedicated structures installed in the TestBeam Line (TBL) and in the Two-Beam Test Stand(TBTS) aimed at delivering bursts of 12 GHz RF power.In the TBTS this power is used to generate a highaccelerating gradient of 100 MV/m in specially designedaccelerating structures. To assess the performances ofthese structures a probe beam is used, produced by asecond Linac. We report here various experimentsconducted in the TBTS making use of the versatility ofthe probe beam and of dedicated diagnostics.

• 10.
CEA/DSM/IRFU Saclay, France.
CEA/DSM/IRFU Saclay, France. CEA/DSM/IRFU Saclay, France. CEA/DSM/IRFU Saclay, France. CEA/DSM/IRFU Saclay, France. CEA/DSM/IRFU Saclay, France. CERN, Geneva. CERN, Geneva. CERN, Geneva. CERN, Geneva. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
CTF3 probe beam LINAC commissioning and operations2010In: Linear Accelerator Conference LINAC2010 - ProceedingsTsukuba, Japan, 2010, p. 46-48Conference paper (Refereed)
• 11.
Brookhaven national laboratory.
Uppsala University, The Svedberg Laboratory. Brookhaven national laboratory. Uppsala University, The Svedberg Laboratory. JINR, Dubna. JINR, Dubna. Uppsala University, The Svedberg Laboratory.
Experimental studies of the magnetized friction force2006In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 74, no 6, article id 066503Article in journal (Refereed)

High-energy electron cooling, presently considered as an essential tool for several applications in high-energy and nuclear physics, requires an accurate description of the friction force which ions experience by passing through an electron beam. Present low-energy electron coolers can be used for a detailed study of the friction force. In addition, parameters of a low-energy cooler can be chosen in a manner, to reproduce regimes expected in future high-energy operation. Here, we report a set of dedicated experiments in CELSIUS aimed at a detailed study of the magnetized friction force. Some results of the accurate comparison of experimental data with the friction force formulas are presented.

• 12.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Proposal for Design and Test of a 352 MHz Spoke RF Source2012Report (Other academic)

More than a dozen of spoke resonators prototypes (SSR, DSR, TSR) have been constructed and tested worldwide. None have accelerated beam until now and the ESS LINAC will be the first accelerator to operate with spoke cavities. Experience with other types of superconducting cavities indicates that high-power test is vital for reliable operation of the cavity in an accelerator. Although characteristics of a bare cavity can be obtained in a low-power test some important features of a dressed' cavity like the electroacoustic stability and tuning system can be studied only in a high-power test stand. The ESS LINAC is a pulsed machine and the Lorentz detuning originating from the electromagnetic pressure on the cavity walls is expected to be strong. The Lorentz force along with the cavity sensitivity to mechanical excitations at some resonant frequencies may lead to self-sustained mechanical vibrations which make cavity operation dicult. Practical experience shows that increasing the boundary stiness will decrease the static Lorentz force detuning but not necessarily the dynamic one. Therefore, the FREIA group at Uppsala University is building a high-power test stand able to study performance of the ESS spoke cavity at high power. The RF test stand will be able to drive the cavity not only in the self-excitation mode but also with closed RF loop and fixed frequency. The later technique will be used to reproduce the shape of the cavity voltage pulse as it is expected to be in the cavity operating in the ESS LINAC such that the cavity tuning compensation system will be tested under realistic conditions.

• 13.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Self-amplified coherent spontaneous emission in a free electron laser with "quiet" bunches2013In: Physical Review Special Topics. Accelerators and Beams, ISSN 1098-4402, E-ISSN 1098-4402, Vol. 16, no 3, p. 030702-Article in journal (Refereed)

For a planar free electron laser (FEL) configuration we study self-amplified coherent spontaneous emission driven by a gradient of the bunch current in the presence of different levels of noise in bunches. The longitudinal granularity of the electron bunch density originating from shot noise is maintained throughout the analysis. For the FEL model with the SwissFEL injector bunch parameters, we calculate the probability density distribution of the maximum power of the radiation pulses for different levels of shot noise. It turns out that the temporal coherence quickly increases as the noise level reduces. We also show that the FEL based on coherent spontaneous emission produces almost Fourier transform limited pulses. The analysis indicates that the time-bandwidth product is mainly determined by the bunch length and the interaction distance in an undulator. Calculations of the FEL characteristics for different rise times of the front of the current pulse are performed, and it is found that a reduced level of the power fluctuations is preserved for the bunch current pulse with a front duration up to several FEL wavelengths. We also propose a novel scheme that permits the formation of electron bunches with a reduced level of noise and a high gradient of the current at the bunch tail to enhance coherent spontaneous emission. The presented scheme uses effects of noise reduction and controlled microbunching instability and consists of a laser heater, a bunch compressor, and a shot noise suppression section. We show that shot noise reduction by 2 orders of magnitude in electron bunches produced by the SwissFEL injector can be achieved in a compact noise suppression section. The noise factor and microbunching gain of the overall proposed scheme with and without laser heater are estimated.

• 14.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
RF Power Consumption in the ESS Spoke LINAC: ESS TDR Contribution2013Report (Other academic)

• 15.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
Analytic Space-Charge Model for Gaussian Beams with cross-plane Coupling2017Report (Other academic)

Intensities of particle beams provided by particle accelerators are raised to levels where the self-interaction of the beam particles due to electromagnetic repulsion, the so-called space-charge effect, becomes a dominant factor. It is therefore indispensable to understand the effects on the beam dynamics in the presence of strong space charge forces. As complement to existing simulation methods, we present a fully analytic space charge model valid for transverse Gaussian beams and which includes non-linear space charge forces and cross-plane coupling. We verify the validity of the model by running test simulations in a few accelerator lattice examples. Finally, we briefly explore the possibilities for future simulations regarding new insights in beam dynamics and show initial results of the development of a beam envelope (core) in a test ring, as well as the dynamics of passive spectator particles which observe the non-linear electric field generated by a beam core.

• 16.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
General-purpose spectrometer for vacuum breakdown diagnostics for the 12 GHz test stand at CERN2014Conference paper (Other academic)
• 17.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. CERN, CH-1211 Geneva 23, Switzerland. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Spectrometers for RF breakdown studies for CLIC2016In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 828, p. 63-71Article in journal (Refereed)

An e(+)e(-) collider of several TeV energy will be needed for the precision studies of any new physics discovered at the LHC collider at CERN. One promising candidate is CLIC, a linear collider which is based on a two-beam acceleration scheme that efficiently solves the problem of power distribution to the acceleration structures. The phenomenon that currently prevents achieving high accelerating gradients in high energy accelerators such as the CLIC is the electrical breakdown at very high electrical field. The ongoing experimental work within the CLIC collaboration is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. In order to validate the feasibility of accelerating structures and observe the characteristics of the vacuum discharges and their eroding effects on the structure two dedicated spectrometers are now commissioned at the high-power test-stands at CERN. First, the so called Flashbox has opened up a possibility for non-invasive studies of the emitted breakdown currents during two-beam acceleration experiments. It gives a unique possibility to measure the energy of electrons and ions in combination with the arrival time spectra and to put that in context with accelerated beam, which is not possible at any of the other existing test-stands. The second instrument, a spectrometer for detection of the dark and breakdown currents, is operated at one of the 12 GHz stand-alone test-stands at CERN. Built for high repetition rate operation it can measure the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. Two new analysis tools: discharge impedance tracking and tomographic image reconstruction, applied to the data from the spectrometer make possible for the first time to obtain the location of the breakdown inside the structure both in the transversal and longitudinal direction thus giving a more complete picture of the vacuum breakdown phenomenon.

• 18.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Spectrometers for RF breakdown studies for CLIC2016Report (Other academic)

A e+e- collider of several TeV energy will be needed for the precision studies of any new physics discovered atthe LHC collider at CERN.  One promising candidate is CLIC, a linear collider which is based on a two-beam acceleration scheme that efficiently solves the problem of power distribution to the acceleration structures. The phenomenon that currently prevents achieving highaccelerating gradients in high energy accelerators such asthe CLIC is the electrical breakdown at very high electrical field.The ongoing experimental work within the CLIC collaboration is trying to benchmark the theoretical models focusing on the physics of vacuum breakdown which is responsible for the discharges. In order to validate the feasibility of accelerating structures and observe the characteristics of the vacuum discharges and their eroding effects on the structure two dedicated spectrometers are now commissioned at the high-power test-stands at CERN. First, the so called Flashbox has opened up a possibility for non-invasive studies of  the emitted breakdown currents during two-beam acceleration experiments. It gives an unique possibility to measure the energy of electrons and ions in combination withthe arrival time spectra and to put that in context with accelerated beam, which is not possible at any of the other existing test-stands.The second instrument, a spectrometer for detection of the dark and breakdown currents, is operated at one of the 12 GHz stand-alone test-stands at CERN.  Built for high repetition rate operation it can measure the spatial and energy distributions of the electrons emitted from the acceleration structure during a single RF pulse. Two new analysis tools: discharge impedance tracking and tomographic image reconstruction, applied to the data from the spectrometer make possible for the first time to obtain the location of the breakdown inside the structure both in the transversal and longitudinal direction thus giving a more complete picture of the vacuum breakdown phenomenon.

• 19.
Uppsala University, The Svedberg Laboratory.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Arrival time measurements of ions accompanying RF breakdown2008In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 595, no 3, p. 568-571Article in journal (Refereed)

Radio-frequency structures for future normal-conducting linear accelerators are limited in accelerating gradient levels by RF breakdown in the structures due to extreme electric field levels. We report of experiments conducted at the CLIC Test Facility CTF3 where the breakdown is sometimes accompanied by a burst of ions that shows a spectrum consistent with hot coulomb explosions.

• 20. Kochetov, B.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Green function approach to the problem of electromagnetic field excitation in THz free electron lasers2012In: Mathematical Methods in Electromagnetic Theory, 2012, p. 357-360Conference paper (Refereed)

The problem of stimulated spontaneous emission in a free electron laser oscillator with planar waveguide and cylindrical mirrors is under consideration. An efficient computational scheme for calculation of the electromagnetic radiation driven by short electron bunches is proposed. Using expansion of the electromagnetic field in a planar waveguide over optical-waveguide modes the inhomogeneous Klein-Gordon equation governing the mode amplitude has been derived. The reflected from mirrors electromagnetic radiation is described in the framework of initial-boundary problem for the homogeneous 1D Klein-Gordon equation. The Green function approach to the Klein-Gordon equation allowed us to obtain an unconditionally stable and computationally efficient numerical scheme describing the self-consistent evolution of electron bunches and electromagnetic fields.

• 21.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Instrumental developments for in situ breakdown experiments inside a scanning electron microscope2011In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 657, no 1, p. 122-125Article in journal (Refereed)

Electrical discharges in accelerating structures are one of the key issues limiting the performance of future high energy accelerators such as the Compact Linear Collider (CLIC). Fundamental understanding of breakdown phenomena is an important part of the CLIC feasibility study. The present work concerns the experimental study of breakdown using Scanning Electron Microscopes (SEMs). An SEM gives us the opportunity to achieve high electrical gradients of 1 kV/mu m which corresponds to 1 GV/m by exciting a probe needle with a high voltage power supply and controlling the positioning of the needle with a linear piezo motor. The gap between the needle tip and the surface is controlled with sub-micron precision. A second electron microscope equipped with a Focused Ion Beam (FIB) is used to create surface corrugations and to sharpen the probe needle to a tip radius of about 50 nm. Moreover it is used to prepare cross-sections of a voltage breakdown area in order to study the geometrical surface damages as well as the elemental composition of the breakdown.

• 22.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala Univ, Dept Phys & Astron, S-75120 Uppsala, Sweden..
CERN, European Org Nucl Res, CH-1211 Geneva 23, Switzerland.. CERN, European Org Nucl Res, CH-1211 Geneva 23, Switzerland.. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Time-resolved momentum and beam size diagnostics for bunch trains with very large momentum spread2015In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 797, p. 234-246Article in journal (Refereed)

We propose a novel method to measure he Lime -resolved momentum dislribulion and size of beams with very large momentum spread. To demonstrate the principle we apply the method to the beam at the end of a Compact Linear Collider decelerator, where conventional diagnostic methods are hampered by the large energy spread of the drive beam after up to 90% of its kinetic energy is converted into microwave power. Our method is based on sweeping the beam in a circular pattern to determine the momentum distribution and recording the beam size on a screen using optical transition radiation. We present an algorithm to extract the time-resolved momentum distribution. Furthermore, the beam size along the bunch train can be extracted from the image left On a screen by sweeping the beam linearly. We introduce he analysis technique and show simulation results that allow us to estimate the applicability, in addition, we present a conceptual design of the technical realization.

• 23.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
University of Oslo, Norway. CERN, European Organization for Nuclear Research, Geneva, Switzerland. CERN, European Organization for Nuclear Research, Geneva, Switzerland. CERN, European Organization for Nuclear Research, Geneva, Schweiz. CERN, European Organization for Nuclear Research, Geneva, Switzerland. CERN, European Organization for Nuclear Research, Geneva, Switzerland. CERN, European Organization for Nuclear Research, Geneva, Switzerland. CERN, European Organization for Nuclear Research, Geneva, Switzerland. CERN, European Organization for Nuclear Research, Geneva, Switzerland. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Beam profile monitoring at the test beam line at the Compact Linear Collider test facility2013In: Physical Review Special Topics. Accelerators and Beams, ISSN 1098-4402, E-ISSN 1098-4402, Vol. 16, no 8, p. 082802-Article in journal (Refereed)

The Compact Linear Collider, CLIC is a study for a future linear electron-positron collider based on a two-beam acceleration scheme in which a high intensity drive beam is decelerated in order to provide the power to accelerate the main beam for collision in the TeV range. The power extracted from the drive beam deteriorates the beam quality and increases the energy spread significantly. Monitoring of the beam properties is therefore challenging but essential. These challenges are being addressed experimentally at the CLIC Test Facility where up to 55% of the power is extracted from the beam in the test beam line, TBL, a small-scale version of the CLIC drive beam decelerator, leaving the beam with a very wide energy profile. For monitoring of the transverse beam profile and Twiss parameters we use Optical Transition Radiation screens and quadrupole scans. The intra-pulse train energy spectrum before and after deceleration is measured with segmented beam dumps. In this report we discuss the performance of these diagnostic devices with a particular emphasis on the large energy spread and its effect on the beam imaging techniques, and with a final outlook to the CLIC drive beam diagnostics.

• 24.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. European Spallation Source.
PROGRESS AT THE FREIA LABORATORY2015In: Proceedings of IPAC'15, JACoW: The Joint Accelerator Conferences Website , 2015Conference paper (Refereed)

The FREIA Facility for Research Instrumentation and Accelerator Development at Uppsala University, Sweden, has reached the stage where the testing of superconducting cavities for the European Spallation Source (ESS) is starting. The new helium liquefaction plant has been commissioned and now supplies a custom-made, versatile horizontal cryostat, HNOSS, with liquid helium at up to 140 l/h. The cryostat has been designed and built to house up to two accelerating cavities, or, later on, other superconducting equipment such as magnets or crab cavities. A prototype cavity for the spoke section of the ESS linac will arrive mid 2015 for high-power testing in the horizontal cryostat. Two tetrode-based commercial RF power stations will deliver 400 kW peak power each, at 352 MHz, to the cavity through an RF distribution line developed at FREIA. In addition, significant progress has been made with in-house development of solid state amplifier modules and powercombiners for future use in particle accelerators. We report here on these and other ongoing activities at the FREIA laboratory.

• 25.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. CERN. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
ON THE SUITABILITY OF A SOLENOID HORN FOR THE ESS NEUTRINO SUPERBEAM2015In: Proceedings of IPAC'15, JACoW , 2015Conference paper (Other academic)

The European Spallation Source (ESS), now under construction in Lund, Sweden, offers unique opportunities for experimental physics, not only in neutron science but potentially in particle physics. The ESS neutrino superbeam project plans to use a 5 MW proton beam from the ESS linac to generate a high intensity neutrino superbeam, with the final goal of detecting leptonic CP-violation in an underground megaton Cherenkov water detector. The neutrino production requires a second target station and a complex focusing system for the pions emerging from the target. The normal-conducting magnetic horns that are normally used for these applications cannot accept the 2.86 ms long proton pulses of the ESS linac, which means that pulse shortening in an accumulator ring would be required. That, in turn, requires H- operation in the linac to accommodate the high intensity. As an attractive alternative, we investigate the possibility of using superconducting solenoids for the pion focusing. This solenoid horn system needs to also separate positive and negative pion charge as completely as possible, in order to generate separately neutrino and anti-neutrino beams. We present here progress in the study of such a solenoid horn.

• 26.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Effect of large momentum spread on emittance measurements2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 707, p. 114-119Article in journal (Refereed)

We discuss the systematic errors in emittance measurements with quadrupole scans and four screens due to large momentum spread in the beam. This is particularly relevant in the drive beam complex of CLIC and the test beam line TBL in the CTF3 facility at CERN. We also discuss methods to adapt the model to correct for the systematic errors.

• 27.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Emittance and Momentum Diagnostics for Beams with Large Momentum Spread2013In: Proceedings of the International Beam Instrumentation Conference IBIC2013, 2013, p. -40Conference paper (Other academic)

Commonly used beam diagnostic methods, such as spectrometry or emittance measurements through quadrupolescans, are based on the assumption that the beam momentum spread is very small. This assumption is sometimes notfulfilled, which leads to a systematic misinterpretation ofthe measurement. We have studied this effect and presentalgorithms that consider the full momentum distributionand offer correct ways of analyzing the profile measurements.

• 28.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
CEA/DSM/IRFU, Saclay, France. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Effects of RF breakdown on the beam in a CLIC prototype accelerator structureManuscript (preprint) (Other academic)

Understanding the effects of RF breakdown in high-gradient accelerator structures on the accelerated beam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) and is one of the main issues addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN. During a RF breakdown large electro-magnetic fields are generated and produce parasitic magnetic fields which interact with the accelerated beam affecting its orbit and energy. We discuss here measurements of such effects observed on an electron beam accelerated in a CLIC prototype structure. Measurements of the trajectory of bunch-trains on a nanosecond time-scale showed fast changes in correspondence of breakdown which we compare with measurements of the relative beam spots on a scintillating screen. We identify different breakdown scenarios for which we offer an explanation based also on measurements of the power at the input and output ports of the accelerator structure. Finally we present the distribution of the magnitude of the observed changes in the beam orbit and we discuss its correlation with RF power and breakdown location in the accelerator structure.

• 29.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. CEA/DSM/IRFU, Saclay, France.
RF-breakdown Kicks at the CTF3 Two-beam Test Stand2012Conference paper (Refereed)

The measurement of the effects of RF-breakdown on the beam in CLIC prototype accelerator structures is one of the key aspects of the CLIC two-beam acceleration scheme being addressed at the Two-beam Test Stand (TBTS) at CTF3. RF-breakdown can randomly cause energy loss and transverse kicks to the beam. Transverse kicks have been measured by means of a screen intercepting the beam after the accelerator structure. In correspondence of a RF-breakdown we detect a double beam spot which we interpret as a sudden change of the beam trajectory within a single beam pulse. To time-resolve such effect, the TBTS has been equipped with five inductive Beam Position Monitors (BPMs) and a spectrometer line to measure both relative changes of the beam trajectory and energy losses. Here we discuss the methodology used and we present the latest results of such measurements.

• 30.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. CEA/DSM/IRFU Saclay, France.
Effects of rf breakdown on the beam in the Compact Linear Collider prototype accelerator structure2013In: Physical Review Special Topics. Accelerators and Beams, ISSN 1098-4402, E-ISSN 1098-4402, Vol. 16, no 8, p. 081004-Article in journal (Refereed)

Understanding the effects of rf breakdown in high-gradient accelerator structures on the acceleratedbeam is an extremely relevant aspect in the development of the Compact Linear Collider (CLIC) andis one of the main issues addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN.During a rf breakdown high currents are generated causing parasitic magnetic ﬁelds that interact withthe accelerated beam affecting its orbit. The beam energy is also affected because the power is partlyreﬂected and partly absorbed thus reducing the available energy to accelerate the beam. We discusshere measurements of such effects observed on an electron beam accelerated in a CLIC prototypestructure. Measurements of the trajectory of bunch trains on a nanosecond time scale showed fastchanges in correspondence of breakdown that we compare with measurements of the relative beamspots on a scintillating screen. We identify different breakdown scenarios for which we offer anexplanation based also on measurements of the power at the input and output ports of the acceleratorstructure. Finally we present the distribution of the magnitude of the observed changes in the beamposition and we discuss its correlation with rf power and breakdown location in the acceleratorstructure.

• 31.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. SLAC National Accelerator Laboratory. SLAC National Accelerator Laboratory. SLAC National Accelerator Laboratory. SLAC National Accelerator Laboratory.
High-gradient test of a X-band accelerator structure assembled in a klystron-driven resonant ringIn: Physical Review Special Topics. Accelerators and Beams, ISSN 1098-4402, E-ISSN 1098-4402Article in journal (Refereed)
• 32.
Uppsala University, Interfaculty Units, The Svedberg Laboratory.
Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research.
A New Neutron Facility for Single-Event Effect Testing2004In: IEEE Nuclear and Space Radiation Effects Conference (NSREC'2004), 2004, p. 160-162Conference paper (Other (popular scientific, debate etc.))
• 33.
Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Neutron Research, Applied Nuclear Physics.
A new neutron beam facility at TSL2006In: International workshop on Fast Neutron Detectors and Applications,Cape Town, South Africa, April 3-6, 2006, p. 016-Conference paper (Refereed)
• 34.
Uppsala University, Interfaculty Units, The Svedberg Laboratory. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Department of Neutron Research. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
A New Neutron Beam Facility at TSL2007In: Tenth Symposium on Neutron Dosimetry,Uppsala, Sweden, June 12-16, 2006 (accepted)., 2007Conference paper (Refereed)
• 35.
Uppsala University, Interfaculty Units, The Svedberg Laboratory. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Department of Neutron Research. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Interfaculty Units, The Svedberg Laboratory. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
A new neutron facility for single-event effect testing2005In: IEEE International Reliability Physics Symposium (IRPS2005),San Jose, California, USA, April 17-21, 2005 (accepted)., 2005Conference paper (Refereed)
• 36.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Tests of the Spoke Cavity RF Source and Cryomodules in Uppsala: ESS TDR Contribution2012Report (Other academic)
• 37.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
The Cryogenic System at the FREIA Laboratory2015Report (Other academic)
• 38.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
The CTF3 Two-beam Test Stand2013In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 729, p. 546-553Article in journal (Refereed)

The Two-beam Test Stand (TBTS) has been constructed and operated at the CLIC test facility CTF3 at CERN. The TBTS comprises two parallel and independent electron beam lines and has been designed to demonstrate the feasibility of a two-beam high gradient acceleration concept as proposed for the Compact Linear Collider (CLIC). In the CLIC scheme, the RF power is extracted from a high current drive beam using RF power extraction structures while the main beam is accelerated using this RF power which is fed into high gradient high frequency normal conducting accelerating structures. The Two-beam Test Stand is a unique facility to demonstrate the feasibility of the CLIC two-beam high gradient acceleration concept and to test the individual CLIC components and complete two-beam CLIC modules. The TBTS is particularly well suited to investigate the effects on the beam of RF breakdown in the high gradient accelerating structures. We report on the design, construction and commissioning of the Two-beam Test Stand.

• 39.
Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Power Supplies for Tetrode High Power Amplfiers at FREIA: ESS TDR Contribution2012Report (Other academic)

This paper select the topology of the power supplies to the RF power amplifier to one spoke cavity to be tested at FREIA Uppsala University.The power supplies are thought to fulfill the requirements of ESS in Lund.

The amplifiers pulsed operation will have a strong impact of the choice of topology. The RF amplifier will have two tetrodes in the final stage.

The anode power supply is studied for different topologies and number of anodes to supply.

Storing the energy for pulse current to the anodes at high voltage or at low voltage is considered.

The short circuit protection can be with a crowbar or a series switch. The series switch is selected for reasons of short interrupts in case of temporary short circuits.

The grid and filament supplies are thought to be standard of the shelf power supplies.

Cost estimate and comments on maintenance in the end of the paper.

• 40.
Uppsala University, Interfaculty Units, The Svedberg Laboratory.
Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics.
A Test Facility for micro Machining and Other Applications of Ion-assisted Etching Technology1996In: Abstract Book of the Tenth Int. Conf.on Thin Films, 1996Conference paper (Other scientific)
• 41.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. CERN, Geneve, Schweiz.
Uppsala high power test stand for ESS spoke cavities2012In: Proceedings of LINAC2012, 2012, p. 711-713Conference paper (Refereed)
• 42.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Selection of RF Power Source and Distribution Scheme at 352 MHz for Spoke Cavities at ESS and FREIA2012Report (Other academic)

The report describes selection of RF power source and distribution scheme for spoke cavities at ESS and FREIA.  The European Spallation Source (ESS) is the world’s most powerful neutron source, which contain 36 superconducting spoke cavities at 352MHz and provide power of 0.5MW to the beam. The baseline for the RF system is a point-to-point generation and distribution  from a single source to a single accelerating cavity.The RF system that has to generate this power and distribute it to the accelerating cavities, is a main resource driver for linear accelerators in form of investment, operation and maintenance. Therefore the technical alternatives are compared to minimize capital and running cost of the accelerator, without compromising its reliability. At 352 MHz and 350 kW RF power output, tetrode amplifiers are selected because of their advantages of being cheap, reliable, simple and efficient as compared to the other RF power amplifiers. The tetrodes, due to their low gain, need a pre-driver. The solid state amplifier technology is selected as a pre-driver due to its simplicity, reliability and efficiency. Half height aluminum WR2300 wave guides shall be used for RF distribution. This solution makes it possible to discard the circulator from the RF distribution chain, thus improving system efficiency.

• 43. Ziemann, V
Uppsala University, Interfaculty Units, The Svedberg Laboratory. Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Neutron Research.
A New Mono-energetic Neutron Beam Facility in the 20-180 MeV Range2004In: Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), 2004, p. 2750-2752Conference paper (Other scientific)
• 44.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
Beam Optics Primer using Octave or MATLAB2019Report (Other academic)

This primer provides a basic introduction to beam optics concepts that arecommonly used to describe charged particle accelerators.

• 45.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Charged Particle Transport, Gaussian Optics, Error Propagation: It's all the same2015Report (Other academic)

We derive a correspondence between the parameters used in Gaussian

light beam propagation with wavelength λ, beam size ω, and wavefront

curvature ρ with the description in terms of emittance and Twiss parameters

commonly used in charged particle optics. Furthermore, we discuss

the analogy of transporting beams to the propagation of measurement uncertainties.

• 46.
Uppsala University, Interfaculty Units, The Svedberg Laboratory.
Comparison of Non-Linear Effects from the Electric Field of Several Current Distributions2006In: Nuclear Instruments and Methods A, Vol. 556, p. 45-51Article in journal (Refereed)

New electron coolers are equipped with electron guns that can create parabolic or hollow beams. With their corresponding electric field this may have a detrimental influence on the stability of the ion beam and lead to `electron heating.'' Here we investigate the effect of the transverse electric field of the electron beam in an electron cooler on an ion beam for different transverse current distributions.

• 47.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.

We deduce a simple equation that describes the irradiation pattern of radiationdetectors along the beam pipe due to a localized source from which a beam is scattered.

• 48.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
GeoScope, a system to finger-print vibrations2017Report (Other academic)

We describe a system that interfaces a SM-24 geophone to a NodeMCU micro-controller and allows to display spectrograms on any web browser. The independent sensor nodes can be very exibly placed anywhere because they are battery-powered and connected to the network by WIFI. The presentation software is based on Javascript and can be used in an Internet browser on any computer connected to the same network.

• 49.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA.
Gyroscope, tracking 3D-motion via WIFI2017Report (Other academic)

By connecting a MPU-6050 or MPU-9250 accelerometer with built-in angular velocitymeasurement capabilities to a ESP8266 WIFI dongle it is possible to track motionin three dimensions on any browser connected to a network. This system can be used to visualize for example the motion of rigid bodies in lab courses.

• 50.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, FREIA. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics.
Luminosity Loss due to Kicks and Mismatch from radio-frequency breakdown in a Linear Collider2017Report (Other academic)

We calculate the geometric luminosity loss caused by filamentation oftransverse kicks, upright and skew quadrupolar errors due to discharges, so-called RF-breakdown, in the acceleration structures of a Linear Collider.

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