Radiation hardness and performance of the hadron calorimeter designed for Projectile Spectator Detection in the Framework of international collaboration CBM@FAIR

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F21%3A00557367" target="_blank" >RIV/61389005:_____/21:00557367 - isvavai.cz</a>

Result on the web

<a href="https://www.fjfi.cvut.cz/cz/studium/doktorske-studium/archiv-doktorskych-praci/1001-mikhaylov-vasily" target="_blank" >https://www.fjfi.cvut.cz/cz/studium/doktorske-studium/archiv-doktorskych-praci/1001-mikhaylov-vasily</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Radiation hardness and performance of the hadron calorimeter designed for Projectile Spectator Detection in the Framework of international collaboration CBM@FAIR

Original language description

The Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR) will investigate the phase diagram of strongly interacting matter at neutron star core densities under laboratory conditions. It is a fixed target heavy-ion collision experiment operating in the medium energy range, i.e. 2 - 11 AGeV for gold ions. Projectile Spectator Detector (PSD) reconstructs the collision centrality and reaction plane orientation from the energy distribution of non-interacting nucleons and fragments emitted at very low polar angles in the forward direction. It is a compensating lead/scintillator hadron calorimeter with a light readout via wavelength shifting (WLS) fibers coupled to Silicon Photomultipliers (SiPM). Since it will operate at an extremely high collision rate up to 1 MHz, the expected high radiation load becomes one of the challenges in the design of the detector. This thesis focuses on the evaluation of the PSD radiation hardness. Active detector components, including polystyrene scintillators, WLS-fibers, and SiPMs, are the most susceptible to radiation damage. The first part of the presented work is devoted to an extensive review of a wide scope of relevant irradiation studies. It includes the interaction of radiation with detectors, the details of detector operation, and radiation-induced effects. As the outcome of this review, anticipated radiation tolerance limits and recommendations for its improvement are provided. The following part presents PSD design upgrades that helped to reduce the radiation load by a factor of 10. In the final design, dose up to 1 kGy for scintillators and 1 MeV equivalent neutron fluence up to 2 × 1011 neq/cm2 for SiPMs are expected after a year of operation. Based on the reviewed data and results of the proton irradiation for scintillators at cyclotron of Nuclear Physics Institute of the CAS, only minor light yield degradation is expected after ten years of operation. In the next parts, a detailed investigation of the radiation hardness for multiple SiPMs produced by Hamamatsu, Ketek, Sensl, and Zecotek is presented. This includes neutron irradiations at NPI cyclotron, development of the measurement setup and software, laboratory tests, tests at the calorimeter module at CERN, and data analysis. Significant SiPM degradation after irradiation was observed which is in agreement with data reported by other studies. Discrepancies with other studies are addressed. Presented experiments produced several unique observations. The first is the improvement of radiation hardness with the reduction of SiPM pixel size. The second unique observation is the evaluation of the dependence of the calorimeter energy resolution on fluence achieved by SiPMs. Tests at CERN proved that Hamamatsu SiPMs with small 10 × 10 µm2 pixels are sufficiently hard to withstand the radiation level at CBM for at least a year. at least a year in the zone with the highest radiation load. After that, they can be exchanged, if necessary. The experiments concluded in detailed recommendations on how to achieve improvement of the SiPM radiation hardness and mitigate calorimeter performance degradation. Finally, in the last part of this thesis the results of simulations of Au+Au collisions with UrQMD, HSD, DCM-QGSM, and LA-QGSM at the CBM energy range are reported. It was demonstrated that the selection of a generator does not significantly affect the reaction plane resolution. Based on the simulation results, DCM-QGSM was selected for further PSD performance studies. This generator showed, although marginally, better resolution, which can be explained by the presence of fragments and the strongest directed particle flow.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20305 - Nuclear related engineering; (nuclear physics to be 1.3);

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů