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Conroy, Sean
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Publications (10 of 578) Show all publications
Rigamonti, D., Dal Molin, A., Muraro, A., Rebai, M., Giacomelli, L., Gorini, G., . . . Tardocchi, M. (2024). The single crystal diamond-based diagnostic suite of the JET tokamak for 14 MeV neutron counting and spectroscopy measurements in DT plasmas. Nuclear Fusion, 64(1), Article ID 016016.
Open this publication in new window or tab >>The single crystal diamond-based diagnostic suite of the JET tokamak for 14 MeV neutron counting and spectroscopy measurements in DT plasmas
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2024 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 64, no 1, article id 016016Article in journal (Refereed) Published
Abstract [en]

The Joint European Torus (JET) has recently conducted its second deuterium-tritium (DT) experimental campaign DTE2, providing unique opportunity for studying both physics and engineering aspects of nuclear fusion plasmas. This also allowed the exploitation of new diagnostics and technologies that were not available during the first JET DT campaign held in 1997. Among these new instruments, the enhancement projects of the JET nuclear diagnostics lead to the development and installation of synthetic single crystal diamond detectors along different collimated line of sights. This paper describes the single crystal diamond-based diagnostic suite of the JET tokamak and the enhanced 14 MeV neutron diagnostic capabilities in terms of neutron yield and high resolution neutron spectroscopy. The diamond characterization measurements and the calibration procedure at JET are shown, together with performance of the diamond based neutron spectrometer as 14 MeV neutron yield monitor which allows the separation of 2.5 MeV and 14 MeV neutrons in trace tritium plasmas. The first high-resolution 14 MeV neutron spectroscopy measurements in neutral beam injection-heated DT plasmas are presented, allowing thermal and non-thermal neutron component separation. Prospects for the diagnose of DT burning plasmas such as ITER and SPARC will be presented.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2024
Keywords
nuclear diagnostics, neutron spectroscopy, single crystal diamond detectors, tokamaks, nuclear fusion diagnostics
National Category
Fusion, Plasma and Space Physics Subatomic Physics Accelerator Physics and Instrumentation Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-518112 (URN)10.1088/1741-4326/ad0a49 (DOI)001107217900001 ()
Available from: 2023-12-21 Created: 2023-12-21 Last updated: 2023-12-21Bibliographically approved
Marcer, G., Zohar, A., Dal Molin, A., Rebai, M., Nocente, M., Panontin, E., . . . Contributors, J. E. (2023). Analytical and MonteCarlo approaches to infer the total gamma ray emission from the JET tokamak. Paper presented at 6th International Conference on Frontiers in Diagnostics Technologies (ICFDT), OCT 19-21, 2022, ENEA, Frascati Res Ctr, Frascati, ITALY. Journal of Instrumentation, 18, Article ID C05020.
Open this publication in new window or tab >>Analytical and MonteCarlo approaches to infer the total gamma ray emission from the JET tokamak
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2023 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 18, article id C05020Article in journal (Refereed) Published
Abstract [en]

A single gamma-ray spectrometer installed at the end of a collimator can be used to infer the total emission from a tokamak plasma if the transport of gamma-rays from the plasma to the detector is known. In such analysis, the plasma emission profile plays a fundamental role, since it impacts the fraction of plasma volume intercepted by the detector line of sight. In this work, the DT 17 MeV fusion gamma-rays emission profile of the JET discharge #99608 from second 46 to 48 has been estimated both with the TRANSP code and reconstructed through tomographic inversion based on the neutron camera data, assuming that fusion gamma-rays have the same profile as the 14 MeV fusion neutrons. The gamma-ray transport has been evaluated both by MonteCarlo simulations and analytical calculations. By combining MonteCarlo and analytical evaluations of the gamma-ray transport in different ways with the estimated radiation emission profile, we provide four different routes to determine the total gamma-ray yield from measurements whose results agree within better than 10%.

Place, publisher, year, edition, pages
IOP Publishing, 2023
Keywords
Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc), Gamma detectors (scintillators, CZT, HPGe, HgI etc), Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators)
National Category
Fusion, Plasma and Space Physics Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-508576 (URN)10.1088/1748-0221/18/05/C05020 (DOI)001026526700001 ()
Conference
6th International Conference on Frontiers in Diagnostics Technologies (ICFDT), OCT 19-21, 2022, ENEA, Frascati Res Ctr, Frascati, ITALY
Available from: 2023-08-07 Created: 2023-08-07 Last updated: 2023-08-07Bibliographically approved
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
Eriksson, B., Conroy, S., Ericsson, G., Eriksson, J., Hjalmarsson, A., Weiszflog, M., . . . Maslov, M. (2023). TOFu: A fully digital data acquisition system upgrade for the neutron time-of-flight spectrometer TOFOR. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1049, Article ID 168126.
Open this publication in new window or tab >>TOFu: A fully digital data acquisition system upgrade for the neutron time-of-flight spectrometer TOFOR
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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 168126Article in journal (Refereed) Published
Abstract [en]

TOFOR is a time-of-flight (TOF) neutron spectrometer located at the Joint European Torus (JET) with a vertical sightline of the JET plasma. It consists of 5 start (denoted S1) and 32 stop (denoted S2) plastic scintillation detectors which can be used in coincidence to generate a TOF spectrum. Spectroscopic analysis of the neutron TOF spectra produced by the JET plasma is regularly performed to determine, e.g., the fuel ion ratio and the presence of fast ion species in the fusion plasma. TOFOR has been upgraded with a new digital data acquisition (DAQ) system, denoted TOFu, which consists of 10 waveform digitizers with a total of 40 channels, 37 of which are connected to the photomultiplier output of the different S1 and S2 detectors. This paper presents a technical overview of the TOFu system and describes the offline analysis capabilities of TOFu which were not available with the previous DAQ system. Two experimental JET discharges are studied and used to show that the signal-to-background ratio is improved by almost 200% for the 2.5 MeV neutron signal and almost 400% for the 14 MeV neutron signal using the new offline analysis capabilities.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
TOFOR, Data acquisition system, TOFu, Time-of-flight, Neutron spectrometry, Joint European Torus
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-504964 (URN)10.1016/j.nima.2023.168126 (DOI)000997950400001 ()
Funder
EU, European Research Council, 101052200-EUROfusion
Available from: 2023-06-16 Created: 2023-06-16 Last updated: 2023-10-18Bibliographically approved
Eriksson, B., Conroy, S., Ericsson, G., Eriksson, J., Hjalmarsson, A., Ghani, Z., . . . King, D. (2022). Determining the fuel ion ratio for D(T)and T(D) plasmas at JET using neutron time-of-flight spectrometry. Plasma Physics and Controlled Fusion, 64, Article ID 055008.
Open this publication in new window or tab >>Determining the fuel ion ratio for D(T)and T(D) plasmas at JET using neutron time-of-flight spectrometry
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2022 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 64, article id 055008Article in journal (Refereed) Published
Abstract [en]

The fusion fuel ion ratio, nΤ/nD, is an important plasma parameter that needs to be tuned to maximize the power of a tokamak type fusion reactor. It is recognized as a parameter required for optimizing several ITER operating scenarios, and will likely be continuously monitored in future high-performance fusion devices such as DEMO. Tritium was recently introduced in the Joint European Torus (JET) plasma for the first time since the 1997 DTE1 and 2003 TTE campaigns, enabling the possibility to investigate fuel ion ratios. We present a method for measuring nΤ/nD using neutron time-of-flight (TOF) spectrometry. By fitting the measured neutron spectral features, the relative reaction rate intensities between different ion species can be inferred, from which the fuel ion ratio can be extracted for a corresponding modeled reactivity. Unlike previous measurements of nT/nD using neutron spectrometry, we utilize the neutron energy continuum produced in the three-body TT reaction to determine the fuel ion ratio for plasmas with large concentrations of tritium. Furthermore, the use of neutron TOF spectrometry has never previously been demonstrated for evaluating nT/nD. The method is applied to TOF spectra acquired with TOFOR (JET name KM11) and shown to be consistent with the optical JET diagnostic KT5P which uses optical spectroscopy of a modified Penning gauge plasma to measure tritium and deuterium concentrations in the divertor exhaust gas.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2022
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-472003 (URN)10.1088/1361-6587/ac5a0d (DOI)000777812000001 ()
Available from: 2022-04-04 Created: 2022-04-04 Last updated: 2023-10-18Bibliographically 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
Mailloux, J., Andersson Sundén, E., Cecconello, M., Conroy, S., Ericsson, G., Eriksson, B., . . . Zychor, I. (2022). Overview of JET results for optimising ITER operation. Nuclear Fusion, 62(4), Article ID 042026.
Open this publication in new window or tab >>Overview of JET results for optimising ITER operation
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2022 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 62, no 4, article id 042026Article in journal (Refereed) Published
Abstract [en]

The JET 2019–2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power in 2019–2020, and tested the technical and procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle (α) physics in the coming D–T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed shattered pellet injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design and operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D–T benefited from the highest D–D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2022
Keywords
overview, D-T preparation, tritium operations, plasma facing components (PFC), nuclear technology, JET with ITER-like wall, isotope
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-482515 (URN)10.1088/1741-4326/ac47b4 (DOI)000829648300001 ()
Funder
European Commission, 633053
Note

For complete list of authors see http://dx.doi.org/10.1088/1741-4326/ac47b4

Available from: 2022-08-25 Created: 2022-08-25 Last updated: 2022-09-30Bibliographically approved
Giacomelli, L., Nocente, M., Cippo, E. P., Rebai, M., Rigamonti, D., Tardocchi, M., . . . Biel, W. (2022). Overview on the progress of the conceptual studies of a gamma ray spectrometer instrument for DEMO. Paper presented at International Conference on Fusion Reactor Diagnostics, SEP 07-11, 2020, Varenna, ITALY. Journal of Instrumentation, 17(8), Article ID C08020.
Open this publication in new window or tab >>Overview on the progress of the conceptual studies of a gamma ray spectrometer instrument for DEMO
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2022 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 17, no 8, article id C08020Article in journal (Refereed) Published
Abstract [en]

The future DEMO tokamak will be equipped with a suite of diagnostics which will operate as sensors to monitor and control the position and operation parameters of DT plasmas. Among the suite of sensors, an integrated neutron and gamma-ray diagnostic system is also studied to verify its capability and performance in detecting possible DEMO plasma position variations and contribute to the feedback system in maintaining DEMO DT plasma in stable conditions. This work describes the progress of the conceptual study of the gamma-ray diagnostic for DEMO reactor performed during the first Work-Package contract 2015-2020. The reaction of interest for this Gamma-Ray Spectrometer Instrument (GRSI) consists of D(T, gamma)He-5 with the emission of 16.63 MeV gamma rays. Due to DEMO tokamak design constraints, the gamma and neutron diagnostics are integrated, both featuring multi-line of sight (camera type), viewing DEMO plasma radially with vertical (12) and horizontal (13) viewing lines to diagnose the. and neutron emission from the DT plasma poloidal section. The GRSI design is based on the investigation of the reaction cross sections, on the calculations performed with GENESIS and MCNP simulation codes and on the physics and geometry constrains of the integrated instrument. GRSI features long collimators which diameters are constrained by the neutron flux at the neutron detectors of the Radial Neutron Camera (RNC) system placed in front, which are key to control DEMO DT plasma position. For these reasons, only few GRSI parameters can be independently selected to optimize its performance. Among these, the choice of the collimator diameters at the back side of the neutron detector box up to the GRSI detector, the use of LiH neutron attenuators in front of the GRSI detectors, the GRSI detector material and shielding. The GRSI detector is based on commercial LaBr3(Ce) inorganic scintillating crystal coupled with a photomultiplier tube or a silicon photomultiplier. They are designed to operate at high count rate although GRSI geometry constraints severely impact on this feature. The GRSI can also provide an independent assessment of DEMO DT fusion power and T burning.

Place, publisher, year, edition, pages
IOP Publishing Ltd, 2022
Keywords
Detector design and construction technologies and materials, Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA), Nuclear instruments and methods for hot plasma diagnostics, Pulsed power
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-501981 (URN)10.1088/1748-0221/17/08/C08020 (DOI)000969780400007 ()
Conference
International Conference on Fusion Reactor Diagnostics, SEP 07-11, 2020, Varenna, ITALY
Available from: 2023-05-22 Created: 2023-05-22 Last updated: 2023-05-22Bibliographically approved
Esposito, B., Marocco, D., Gandolfo, G., Belli, F., Bertalot, L., Blocki, J., . . . Zimbal, A. (2022). Progress of Design and Development for the ITER Radial Neutron Camera. Journal of fusion energy, 41(2), Article ID 22.
Open this publication in new window or tab >>Progress of Design and Development for the ITER Radial Neutron Camera
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2022 (English)In: Journal of fusion energy, ISSN 0164-0313, E-ISSN 1572-9591, Vol. 41, no 2, article id 22Article in journal (Refereed) Published
Abstract [en]

The paper presents an overview of the design status of the Radial Neutron Camera (RNC), that, together with the Vertical Neutron Camera, will provide, through reconstruction techniques applied to the measured line-integrated neutron fluxes, the time resolved measurement of the ITER neutron and alpha-source profile (i.e. neutron emissivity, neutrons emitted per unit time and volume). The RNC is composed of two subsystems, the In-Port RNC and Ex-Port RNC located, respectively, inside and outside the Plug of Equatorial Port #01. The In-Port subsystem is in a more advanced design stage since it has recently undergone the Final Design Review in the ITER procurement process. The paper describes the diagnostic layout, the interfaces, the measurement capabilities and the main challenges in its realization. Prototyping and testing of neutron detectors and electronics components were carried out and led to the choice of the component solutions that can match the environmental and operational constraints in terms radiation hardness, high temperature and electromagnetic compatibility. The performance of the RNC in terms of neutron emissivity measurement capability was assessed through 1D and 2D reconstruction analysis. It is proven that the neutron emissivity can be reconstructed in real-time within the measurement requirements: 10% accuracy, 10 ms time resolution and a/10 (a = plasma minor radius) space resolution.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Neutron detector, Neutron camera, Tomography, ITER
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:uu:diva-486048 (URN)10.1007/s10894-022-00333-9 (DOI)000856510900001 ()
Funder
EU, Horizon 2020EU, Horizon 2020
Available from: 2022-10-14 Created: 2022-10-14 Last updated: 2022-10-14Bibliographically approved
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