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Andersson Sundén, Erik
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Publications (10 of 444) Show all publications
Hägg, L., Binda, F., Conroy, S., Ericsson, G., Ghani, Z., Giacomelli, L., . . . Contributors, J. E. (2023). Estimating the neutron yield in a deuterium plasma with the JET neutron camera. Review of Scientific Instruments, 94(7), Article ID 073502.
Open this publication in new window or tab >>Estimating the neutron yield in a deuterium plasma with the JET neutron camera
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2023 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 94, no 7, article id 073502Article in journal (Refereed) Published
Abstract [en]

The JET neutron camera is a well-established detector system at JET, which has 19 sightlines each equipped with a liquid scintillator. The system measures a 2D profile of the neutron emission from the plasma. A first principle physics method is used to estimate the DD neutron yield that is based on JET neutron camera measurements and is independent of other neutron measurements. This paper details the data reduction techniques, models of the neutron camera, simulations of neutron transport, and detector responses used to this end. The estimate uses a simple parameterized model of the neutron emission profile. The method makes use of the JET neutron camera's upgraded data acquisition system. It also accounts for neutron scattering near the detectors and transmission through the collimator. These components together contribute to 9% of the detected neutron rate above a 0.5 MeVee energy threshold. Despite the simplicity of the neutron emission profile model, the DD neutron yield estimate falls on average within 10% agreement with a corresponding estimate from the JET fission chambers. The method can be improved by considering more advanced neutron emission profiles. It can also be expanded to estimate the DT neutron yield with the same methodology.

Place, publisher, year, edition, pages
AIP Publishing, 2023
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-509254 (URN)10.1063/5.0144654 (DOI)001023449000005 ()37404096 (PubMedID)
Available from: 2023-08-21 Created: 2023-08-21 Last updated: 2023-08-21Bibliographically approved
Hägg, L., Binda, F., Conroy, S., Ericsson, G., Ghani, Z., Giacomelli, L., . . . Andersson Sundén, E. (2023). Estimating the neutron yield in a deuterium plasma with the JET neutron camera. Review of Scientific Instruments, 94(7), Article ID 073502.
Open this publication in new window or tab >>Estimating the neutron yield in a deuterium plasma with the JET neutron camera
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2023 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 94, no 7, article id 073502Article in journal (Refereed) Published
Abstract [en]

The JET neutron camera is a well-established detector system at JET, which has 19 sightlines each equipped with a liquid scintillator. The system measures a 2D profile of the neutron emission from the plasma. A first principle physics method is used to estimate the DD neutron yield that is based on JET neutron camera measurements and is independent of other neutron measurements. This paper details the data reduction techniques, models of the neutron camera, simulations of neutron transport, and detector responses used to this end. The estimate uses a simple parameterized model of the neutron emission profile. The method makes use of the JET neutron camera’s upgraded data acquisition system. It also accounts for neutron scattering near the detectors and transmission through the collimator. These components together contribute to 9% of the detected neutron rate above a 0.5 MeVee energy threshold. Despite the simplicity of the neutron emission profile model, the DD neutron yield estimate falls on average within 10% agreement with a corresponding estimate from the JET fission chambers. The method can be improved by considering more advanced neutron emission profiles. It can also be expanded to estimate the DT neutron yield with the same methodology.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Fusion, Plasma and Space Physics
Research subject
Physics with specialization in Nuclear Physics
Identifiers
urn:nbn:se:uu:diva-512384 (URN)10.1063/5.0144654 (DOI)001023449000005 ()
Available from: 2023-09-25 Created: 2023-09-25 Last updated: 2023-09-25Bibliographically approved
Rathore, V., Senis, L., Håkansson, A., Sundén, E. A. & Andersson, P. (2023). Experimental evaluation of the performance of a novel planar segmented HPGe detector for use in gamma emission tomography. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1049, Article ID 168073.
Open this publication in new window or tab >>Experimental evaluation of the performance of a novel planar segmented HPGe detector for use in gamma emission tomography
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2023 (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. 1049, article id 168073Article in journal (Refereed) Published
Abstract [en]

The use of segmented HPGe detectors for gamma-ray tracking applications is well established. The spectroscopic capabilities of these detectors make them most suitable for such applications. For similar reasons, the use of such detectors in the tomographic measurement of irradiated nuclear fuel has also been envisioned. Especially, these detectors can facilitate faster fuel examination with excellent energy resolution. We have proposed and designed a novel planar segmented HPGe detector for use in gamma emission tomography. The design of the detector segmentation and the mode of operation is unique and offers six simultaneous detection channels for tomographic measurements. This work reports the first experimental evaluation of the performance of the detector. Important characteristics of the detector have been obtained, such as energy resolution of the segments in 1-fold (one segment) and 2-fold (two segments) modes, throughput curves, crosstalk energy corrections, and mislocalisation rate. Collimated source tests have been performed and the results have been compared with the MCNP simulations results. The obtained results are as expected and in good agreement with the simulation results, and it is estimated that using this detector can speed up the data collection by 3.2 times in comparison to an unsegmented detector of the same overall dimensions, in a tomographic application. Further improvements are foreseeable if scaling up to a larger detector with greater segmentation.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Segmented HPGe, Gamma spectroscopy, Gamma emission tomography, MCNP, Post-irradiation examination
National Category
Subatomic Physics
Research subject
Applied Nuclear Physics
Identifiers
urn:nbn:se:uu:diva-495476 (URN)10.1016/j.nima.2023.168073 (DOI)000997247900001 ()
Funder
Swedish Research Council, 2017-06448Swedish Foundation for Strategic Research, EM-16-0031
Available from: 2023-01-28 Created: 2023-01-28 Last updated: 2023-06-28Bibliographically approved
Rathore, V., Senis, L., Holm, S. J., Andersson Sundén, E., Håkansson, A., Laassiri, M., . . . Andersson, P. (2023). First experimental demonstration of the use of a novel planar segmented HPGe detector for gamma emission tomography of mockup fuel rods. Nuclear Technology
Open this publication in new window or tab >>First experimental demonstration of the use of a novel planar segmented HPGe detector for gamma emission tomography of mockup fuel rods
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2023 (English)In: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471Article in journal (Refereed) Published
Abstract [en]

Post-irradiation examination of nuclear fuel is routinely performed to characterize the important properties of the current and the future fuel. Gamma emission tomography is a proven non-invasive technique for this purpose. Among various measurement elements of the technique, a gamma-ray detector is an important element whose spectroscopic abilities and detection efficiency affect the overall results. Finding a combination of high detection efficiency and excellent energy resolution in a single detector is often a challenge. We have designed a novel planar segmented HPGe detector which offers simultaneous measurement in six lines of sight with excellent energy resolution. The simultaneous detection ability enables faster data acquisition in a tomographic measurement which may facilitate achieving higher spatial resolution. In this work, we have demonstrated the first use of the detector by performing a full tomographic measurement of mockup fuel rods. Two methods of detector data analysis were used to make spectra and the images (tomograms) were reconstructed using the filtered back projection algorithm. The reconstructed images validate the successful use of the detector for tomographic measurement. The use of the detector for real fuel measurement is being planned and will be performed in the near future.

Keywords
Segmented HPGe detector; Gamma emission tomography; Post-irradiation examination; Nuclear fuel; Non-destructive fuel testing
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-499373 (URN)10.1080/00295450.2023.2236882 (DOI)
Projects
VR Bränslediagnostik - 113330190
Funder
Swedish Research Council, 2017-06448Swedish Foundation for Strategic Research, EM-16-0031
Available from: 2023-03-29 Created: 2023-03-29 Last updated: 2023-08-29
Sjöstrand, H., Göök, A. & Andersson Sundén, E. (2023). Integral adjustment and fine structure treatment for fusion evaluations. In: : . Paper presented at Nuclear Data Week, JEFF meeting, 27-30 November, 2023, online and Boulogne-Billancourt, France. Nuclear Energy Agency, Article ID effdoc-1523.
Open this publication in new window or tab >>Integral adjustment and fine structure treatment for fusion evaluations
2023 (English)Conference paper, Oral presentation only (Other academic)
Place, publisher, year, edition, pages
Nuclear Energy Agency, 2023
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-517368 (URN)
Conference
Nuclear Data Week, JEFF meeting, 27-30 November, 2023, online and Boulogne-Billancourt, France
Funder
European Commission, 633053
Available from: 2023-12-07 Created: 2023-12-07 Last updated: 2023-12-07Bibliographically approved
Senis, L., Rathore, V., Andersson Sundén, E., Elter, Z., Trombetta, D. M., Håkansson, A. & Andersson, P. (2023). Multi-parameter Optimization of Gamma Emission Tomography Instruments for Irradiated Nuclear Fuel Examination. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1057, Article ID 168698.
Open this publication in new window or tab >>Multi-parameter Optimization of Gamma Emission Tomography Instruments for Irradiated Nuclear Fuel Examination
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2023 (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. 1057, article id 168698Article in journal (Refereed) Published
Abstract [en]

Material test reactors have an extended use in irradiation testing of novel nuclear fuel materials and the fuel behavior in off-normal conditions. The performance of the nuclear fuel is examined in in-pile and out-of-pile post-irradiation examinations (PIEs), e.g., using Gamma Emission Tomography (GET). GET is a nondestructive assay that images the internal spatial distribution of gamma-emitting nuclides built up in the fuel due to irradiation. Since GET can be performed close to the reactor and without intrusion in the fuel object, it can potentially speed up the data generation from PIE in irradiation testing.

The performance metrics of GET devices can be identified regarding time requirements, noise in the reconstructed image, signal-to-background ratio, and spatial resolution. However, these are complicated to determine, partly due to inherent trade-offs between the metrics themselves, partly because they depend on the fuel activity and its spectrum (i.e., object dependent), and, finally, on the GET setup and its configuration. 

This work proposes a structured methodology for optimizing the collimator design for a new generation of GET tomography setups, intending to improve spatial resolution by one order of magnitude: from the millimeter scale to the hundred-micron scale. The conflicting performance metrics are determined based on the controllable parameters of the GET setup and the uncontrollable parameters of an anticipated fuel object, able to provide a signal-to-background ratio above 100. The trade-off between the performance remaining metrics is then visualized by a Pareto approach, where dominated solutions are rejected. Finally, constraints on noise level and measurement time are used to find the optimal spatial resolution. 

Two GET setups are presented using the outlined method. Firstly, to upgrade the tomography test bench BETTAN at Uppsala University, a new segmented HPGe detector was planned to be tested using low-activity fuel rod mock-ups. Secondly, a GET system for investigating high-activity nuclear fuel rods of representative burnup. For a nuclear fuel inspection, the results showed that a spatial resolution of about 300 μm is possible with reasonable noise and measurement time constraints.

Place, publisher, year, edition, pages
Elsevier, 2023
National Category
Accelerator Physics and Instrumentation
Research subject
Applied Nuclear Physics
Identifiers
urn:nbn:se:uu:diva-498896 (URN)10.1016/j.nima.2023.168698 (DOI)001099748800001 ()
Funder
Swedish Foundation for Strategic Research, EM-16-0031
Available from: 2023-03-21 Created: 2023-03-21 Last updated: 2023-12-11Bibliographically approved
Senis, L., Elter, Z., Rathore, V., Andersson Sundén, E., Jansson, P., Holcombe, S., . . . Andersson, P. (2022). A computational methodology for estimating the detected energy spectra of the gamma-ray flux from irradiated nuclear fuel. IEEE Transactions on Nuclear Science, 69(4), 703-713
Open this publication in new window or tab >>A computational methodology for estimating the detected energy spectra of the gamma-ray flux from irradiated nuclear fuel
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2022 (English)In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 69, no 4, p. 703-713Article in journal (Refereed) Published
Abstract [en]

Gamma-ray spectrometry using collimated detectors is a well-established examination method for irradiated nuclear fuel. However, the feasibility of examining a particular nuclide of interest is subject to constraints; the peak must be statistically determinable with the desired precision and the total spectrum count rate in the detector should not cause throughput issues. Methods were assembled for gamma spectrum prediction to optimize instruments for gamma emission tomography and to enable a priori feasibility evaluation of determination of single peaks of irradiated nuclear fuel. The aim was to find reliable results (~10% accuracy) regarding total spectrum and peak count rates with faster computation time than a full-Monte Carlo approach. For this purpose, the method is based on depletion calculations with SERPENT2, a point-source kernel method for the collimator response, a rig response matrix and a detector response matrix, both computed with MCNP6. The computational methodology uses as input the fuel properties (dimensions, materials, power history, and cooling time), and the instrumental setup (collimator and detector dimensions and materials). The prediction method was validated using measured data from a high-burnup, short-cooled test fuel rodlet from the Halden reactor. Absolute count rates and ratios of characteristic peaks were compared between predicted and measured spectra, showing a total count rate overestimation of 7% and discrepancies between 2-20% for the single peaks (same order of magnitude of the uncertainty). This level of agreement is deemed sufficient for measurement campaigns planning, and the optimization of spectroscopic instruments for use in gamma scanning and tomography of nuclear fuel.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2022
Keywords
Gamma emission tomography, Gamma spectroscopy, Nuclear fuel inspection, Post-irradiation examination
National Category
Other Physics Topics
Identifiers
urn:nbn:se:uu:diva-470813 (URN)10.1109/tns.2022.3152264 (DOI)000803113800018 ()
Funder
Swedish Foundation for Strategic Research, EM-16-0031
Available from: 2022-03-29 Created: 2022-03-29 Last updated: 2023-03-28Bibliographically approved
Rathore, V., Senis, L., Jansson, P., Andersson Sundén, E., Håkansson, A. & Andersson, P. (2022). Calculation of Spatial Response of a Collimated Segmented HPGe detector for Gamma Emission Tomography by MCNP Simulations. IEEE Transactions on Nuclear Science, 69(4), 714-721
Open this publication in new window or tab >>Calculation of Spatial Response of a Collimated Segmented HPGe detector for Gamma Emission Tomography by MCNP Simulations
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2022 (English)In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 69, no 4, p. 714-721Article in journal (Refereed) Published
Abstract [en]

We have proposed a planar electronically segmented HPGe detector concept in combination with a multi-slit collimator for gamma emission tomography. In this work, the spatial resolution achievable by using the collimated segmented HPGe detector was evaluated, prior to the manufacture and operation of the detector. The spatial response of a collimated segmented HPGe detector concept was evaluated using simulations performed with Monte Carlo N-Particle transport code MCNP6. The full detector and multi-slit collimator system were modeled and for the quantification of the spatial response, the Modulation Transfer Function (MTF) was chosen as a performance metric. The MTF curve was obtained through the calculation of the Line Spread Function (LSF) by analyzing simulated projection data. In addition, tomographic reconstructions of the simulated simplified test objects were made to demonstrate the performance of the segmented HPGe detector in the planned application. For 662 keV photons, the spatial resolution obtained was approximately the same as the collimator slit width for both 100 and 150 mm long collimators. The corresponding spatial resolution at 1596 keV photon energy was almost twice the slit width for 100 mm collimator, due to the partial penetration of the high-energy gamma rays through the collimator bulk. For a 150 mm long collimator, an improved resolution was obtained.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2022
National Category
Subatomic Physics
Research subject
Applied Nuclear Physics
Identifiers
urn:nbn:se:uu:diva-468474 (URN)10.1109/tns.2022.3152056 (DOI)000803113800019 ()
Projects
VR Bränslediagnostik
Funder
Swedish Foundation for Strategic Research, EM-16-0031Swedish Research Council, 2017-06448
Available from: 2022-02-25 Created: 2022-02-25 Last updated: 2024-01-15Bibliographically approved
Andersson, P., Göök, A., Rathore, V., Andersson Sundén, E., Branger, E., Grape, S., . . . Ringbom, A. (2022). Coincidence spectroscopy for increased sensitivity in radionuclide monitoring. In: : . Paper presented at The first annual conference of the Alva Myrdal Centre for Nuclear Disarmament, 19-22 October 2022, Uppsala & Online.
Open this publication in new window or tab >>Coincidence spectroscopy for increased sensitivity in radionuclide monitoring
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2022 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

The majority of the energy in a nuclear explosion is released in the immediate blast and the initial radiation accounts. The remaining fraction is released through radioactive decay of the explosion's fission products and neutron activation products over a longer time span. This allows for the detection of a nuclear explosion by detecting the presence of residual decay. Radionuclide monitoring stations for detection of radioactive emissions to the atmosphere is thereby an important tool in the verification of compliance with nuclear disarmament treaties. In particular, the globally spanning radionuclide station network of the International Monitoring System (IMS) has been implemented for verification of the Comprehensive Nuclear-Test-Ban Treaty.

High Purity Germanium (HPGe) detectors are workhorses in radionuclide monitoring. The detection of characteristic gamma rays can be used to disclose the presence of signature nuclides produced innuclear weapon tests. A particular development that has potential to improve the sensitivity of radionuclide monitoring is the coincidence technique where decaying nuclides that emit several coincident gamma rays can be detected at much smaller activity concentrations than with conventional gamma spectroscopy.

In this project, dedicated gamma-gamma coincidence detectors are being developed, utilizing electronically segmented HPGe detectors. These detectors are expected to be highly sensitive to low-activity samples of nuclides that present coincident emissions of gamma rays. In this paper we present the concept, define performance parameters, and explore the performance of such detectors to a subset of radionuclides of particular CTBT relevance. In addition, we discuss the path forward in developing a next generation gamma-gamma coincidence spectroscopy system of segmented HPGe.

National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-487068 (URN)
Conference
The first annual conference of the Alva Myrdal Centre for Nuclear Disarmament, 19-22 October 2022, Uppsala & Online
Available from: 2022-10-23 Created: 2022-10-23 Last updated: 2022-11-01Bibliographically approved
Marcinkevicius, B., Eriksson, J., Hjalmarsson, A., Conroy, S. & Ericsson, G. (2022). Fuel ion ratio determination using the 14 MeV Tandem neutron spectrometer for JET DTE1 campaign discharges. Fusion engineering and design, 184, Article ID 113259.
Open this publication in new window or tab >>Fuel ion ratio determination using the 14 MeV Tandem neutron spectrometer for JET DTE1 campaign discharges
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2022 (English)In: Fusion engineering and design, ISSN 0920-3796, E-ISSN 1873-7196, Vol. 184, article id 113259Article in journal (Refereed) Published
Abstract [en]

This paper investigates the determination of the fuel ion ratio nT/ntot in fusion experiments using two different approaches. The methods are applied to plasma discharges from the deuterium-tritium campaign at the Joint European Torus (JET) in 1997. Multiple discharges have been analysed using data acquired with the Tandem (KM2) neutron spectrometer, using a new neutron spectrometer response function and improved line-of-sight information.The two different approaches were generally similar with the exception of the beam slowing down modelling, handled by two different particle transport codes, namely, TRANSP and PENCIL.The results show that nT/ntot can be determined using Tandem neutron spectrometer data; nT/ntot using both of the approaches are consistent and within the uncertainty for a range of studied discharges.The obtained results support previous studies on nT/ntot determination using neutron spectroscopy. In addition, we have shown that PENCIL can be used instead of TRANSP for a range of discharges which could simplify and speed up the estimation of nT/ntot. The possible limitations of the approach using PENCIL could be investigated using different neutron spectrometer data from the 2021 JET deuterium-tritium campaign.A similar spectrometer like Tandem is planned to be operational at ITER and the results of this paper form the first experimental verification of the capability for nT/ntot measurements with such spectrometers. Further research on this could lead to better understanding of these instruments and their limitations before the start of experiments at ITER.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Neutron spectrometer, Hot plasma, JET, Tokamak, Fuel ion ratio
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-487891 (URN)10.1016/j.fusengdes.2022.113259 (DOI)000869406200006 ()
Note

JET (Joint European Torus) medarbetare står som gruppförfattare i artikeln.

Här har de affilierade vid Uppsala Universitet tagits med.

Available from: 2022-11-08 Created: 2022-11-08 Last updated: 2022-11-08Bibliographically approved
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