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Publications (10 of 61) Show all publications
Ziemann, V. (2019). Beam Optics Primer using Octave or MATLAB.
Open this publication in new window or tab >>Beam Optics Primer using Octave or MATLAB
2019 (English)Report (Other academic)
Abstract [en]

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

Publisher
p. 23
Series
FREIA Report ; 2019/03
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-389509 (URN)
Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2019-07-24Bibliographically approved
Ziemann, V., Wedberg, R., Peterson, T. & Wirén, A. (2018). Earth-field Compensation Coils for the Vertical Cryostat in FREIA.
Open this publication in new window or tab >>Earth-field Compensation Coils for the Vertical Cryostat in FREIA
2018 (English)Report (Other academic)
Abstract [en]

We describe the design and construction of coils to compensate the Earth magnetic field in the vertical cryostat in FREIA.

Publisher
p. 27
Series
FREIA Report ; 2018/01
National Category
Accelerator Physics and Instrumentation
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-346574 (URN)
Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-03-21Bibliographically approved
Ögren, J. & Ziemann, V. (2018). Optimum resonance control knobs for sextupoles. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 894, 111-118
Open this publication in new window or tab >>Optimum resonance control knobs for sextupoles
2018 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 894, p. 111-118Article in journal (Refereed) Published
Abstract [en]

We discuss the placement of extra sextupoles in a magnet lattice that allows to correct third-order geometric resonances, driven by the chromaticity-compensating sextupoles, in a way that requires the least excitation of the correction sextupoles. We consider a simplified case, without momentum-dependent effects or other imperfections, where suitably chosen phase advances between the correction sextupoles leads to orthogonal knobs with equal treatment of the different resonance driving terms.

National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-330972 (URN)10.1016/j.nima.2018.03.041 (DOI)000430704600014 ()
Funder
Swedish Research Council, 2011-6305Swedish Research Council, 2014-6360Knut and Alice Wallenberg Foundation
Available from: 2017-10-09 Created: 2017-10-09 Last updated: 2018-08-03Bibliographically approved
Ziemann, V. (2018). PuddlePeeker: a system to monitor the water level at the bottom of the vertical cryostat in FREIA.
Open this publication in new window or tab >>PuddlePeeker: a system to monitor the water level at the bottom of the vertical cryostat in FREIA
2018 (English)Report (Other academic)
Publisher
p. 10
Series
FREIA Report ; 2018/02
Keywords
water level sensor
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-347147 (URN)
Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2018-03-27Bibliographically approved
Ögren, J. & Ziemann, V. (2017). Aligning linac accelerating structures using a copropagating octupolar mode. Physical Review Accelerators and Beams, 20, Article ID 102801.
Open this publication in new window or tab >>Aligning linac accelerating structures using a copropagating octupolar mode
2017 (English)In: Physical Review Accelerators and Beams, ISSN 2469-9888, Vol. 20, article id 102801Article in journal (Refereed) Published
Abstract [en]

We propose a novel method to align accelerating structures such as those used in the Compact Linear Collider (CLIC) by exploiting a mode that copropagates with the normal accelerating mode. This mode has an octupolar dependence in the transverse direction and is caused by radial waveguides intended to damp higher-order modes. The nonlinear dependence of the octupolar mode makes it possible to determine the center of the structure from the nonlinear dependence of the transverse kick, observed on a downstream beam position monitor, while changing the transverse position of the beam with respect to the accelerating structures. We discuss the method, its tolerances and disentangling the individual misalignments of two adjacent accelerating structures that are powered from a single source.

Place, publisher, year, edition, pages
College Park, MD: American Physical Society, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-331616 (URN)10.1103/PhysRevAccelBeams.20.102801 (DOI)000413054500001 ()
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council, 2011-6305Swedish Research Council, 2014-6360
Available from: 2017-10-16 Created: 2017-10-16 Last updated: 2018-01-29Bibliographically approved
Ali, H., Eriksson, J., Li, H., Jafri, S. H., Kumar, M. S., Ögren, J., . . . Leifer, K. (2017). An electron energy loss spectrometer based streak camera for time resolved TEM measurements. Ultramicroscopy, 176, 5-10
Open this publication in new window or tab >>An electron energy loss spectrometer based streak camera for time resolved TEM measurements
Show others...
2017 (English)In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 176, p. 5-10Article in journal (Refereed) Published
Abstract [en]

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.

Keywords
Time resolved; TEM; Energy filter; Streak camera; Sweep
National Category
Physical Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-329982 (URN)10.1016/j.ultramic.2016.11.026 (DOI)000403992200003 ()
Available from: 2017-09-25 Created: 2017-09-25 Last updated: 2017-11-20Bibliographically approved
Holz, M. & Ziemann, V. (2017). Analytic Space-Charge Model for Gaussian Beams with cross-plane Coupling.
Open this publication in new window or tab >>Analytic Space-Charge Model for Gaussian Beams with cross-plane Coupling
2017 (English)Report (Other academic)
Abstract [en]

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.

Publisher
p. 45
Series
FREIA Report ; 2017-13
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-334861 (URN)
Available from: 2017-11-28 Created: 2017-11-28 Last updated: 2017-12-14Bibliographically approved
Ögren, J. & Ziemann, V. (2017). Compensating amplitude-dependent tune-shift without driving fourth-order resonances. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 869, 1-9
Open this publication in new window or tab >>Compensating amplitude-dependent tune-shift without driving fourth-order resonances
2017 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 869, p. 1-9Article in journal (Refereed) Published
Abstract [en]

If octupoles are used in a ring to correct the amplitude-dependent tune-shift one normally tries to avoid that the octupoles drive additional resonances. Here we consider the optimum placement of octupoles that only affects the amplitude-dependent tune-shift, but does not drive fourth-order resonances. The simplest way turns out to place three equally powered octupoles with 60° phase advance between adjacent magnets. Using two such octupole triplets separated by a suitable phase advance cancels all fourth-order resonance driving terms and forms a double triplet we call a six-pack. Using three six-packs at places with different ratios of the beta functions allows to independently control all amplitude-dependent tune-shift terms without exciting additional fourth-order resonances in first order of the octupole excitation.

Keywords
Beam dynamics, Nonlinear beam dynamics
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-329979 (URN)10.1016/j.nima.2017.06.047 (DOI)000409530200001 ()
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council, 2011-6305, 2014-6360
Available from: 2017-09-25 Created: 2017-09-25 Last updated: 2017-12-05Bibliographically approved
Ziemann, V. (2017). Determining Scattering Source Parameters from Radiation Detector Excitation Patterns.
Open this publication in new window or tab >>Determining Scattering Source Parameters from Radiation Detector Excitation Patterns
2017 (English)Report (Other academic)
Abstract [en]

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.

Publisher
p. 6
Series
FREIA Report ; 2017/15
Keywords
Accelerator physics
National Category
Accelerator Physics and Instrumentation
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-335424 (URN)
Available from: 2017-12-05 Created: 2017-12-05 Last updated: 2017-12-14Bibliographically approved
Ziemann, V. (2017). GeoScope, a system to finger-print vibrations. Uppsala University
Open this publication in new window or tab >>GeoScope, a system to finger-print vibrations
2017 (English)Report (Other academic)
Abstract [en]

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.

Place, publisher, year, edition, pages
Uppsala University, 2017. p. 29
Series
FREIA Report ; 03
National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-322948 (URN)
Available from: 2017-05-31 Created: 2017-05-31 Last updated: 2017-06-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6229-5620

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