S. Kushpil

Operation and calibration of the Silicon Drift Detectors of the ALICE experiment during the 2008 cosmic ray data taking period

The calibration and performance of the Silicon Drift Detector of the ALICE experiment during the 2008 cosmic ray run will be presented. In particular the procedures to monitor the running parameters (baselines, noise, drift speed) are detailed. Other relevant parameters (SOP delay, time-zero, charge calibration) were also determined.

Radiation hardness of semiconductor avalanche detectors for calorimeters in future HEP experiments

During the last years, semiconductor avalanche detectors are being widely used as the replacement of classical PMTs in calorimeters for many HEP experiments. In this report, basic selection criteria for replacement of PMTs by solid state devices and specific problems in the investigation of detectors radiation hardness are discussed. The design and performance of the hadron calorimeters developed for the future high energy nuclear physics experiments at FAIR, NICA, and CERN are discussed. The Projectile Spectator Detector (PSD) for the CBM experiment at the future FAIR facility, the Forward Calorimeter for the NA61 experiment at CERN and the Multi Purpose Detector at the future NICA facility are reviewed. Moreover, new methods of data analysis and results interpretation for radiation experiments are described. Specific problems of development of detectors control systems and possibilities of reliability improvement of multi-channel detectors systems are shortly overviewed. All experimental material is based on the investigation of SiPM and MPPC at the neutron source in NPI Rez.

O2: A novel combined online and offline computing system for the ALICE Experiment after 2018

ALICE (A Large Ion Collider Experiment) is a detector dedicated to the studies with heavy ion collisions exploring the physics of strongly interacting nuclear matter and the quark-gluon plasma at the CERN LHC (Large Hadron Collider). After the second long shutdown of the LHC, the ALICE Experiment will be upgraded to make high precision measurements of rare probes at low pT, which cannot be selected with a trigger, and therefore require a very large sample of events recorded on tape. The online computing system will be completely redesigned to address the major challenge of sampling the full 50 kHz Pb-Pb interaction rate increasing the present limit by a factor of 100. This upgrade will also include the continuous un-triggered read-out of two detectors: ITS (Inner Tracking System) and TPC (Time Projection Chamber)) producing a sustained throughput of 1 TB/s. This unprecedented data rate will be reduced by adopting an entirely new strategy where calibration and reconstruction are performed online, and only the reconstruction results are stored while the raw data are discarded. This system, already demonstrated in production on the TPC data since 2011, will be optimized for the online usage of reconstruction algorithms. This implies much tighter coupling between online and offline computing systems. An R&D program has been set up to meet this huge challenge. The object of this paper is to present this program and its first results.

INVESTIGATION OF AVALANCHE PHOTODIODES RADIATION HARDNESS FOR BARYONIC MATTER STUDIES

Modern avalanche photodiodes (APDs) with high gain are good device candidates for light readout from detectors applied in relativistic heavy ion collisions experiments. The results of the investigations of the APDs properties from Zecotek, Ketek and Hamamatsu manufacturers after irradiation using secondary neutrons from cyclotron facility U120M at NPI of ASCR in \v{R}e\v{z} are presented. The results of the investigations can be used for the design of the detectors for the experiments at NICA and FAIR.

Performance of the forward calorimeters for heavy-ion experiments at FAIR, NICA, and CERN SPS

The Projectile Spectator Detectors (PSDs) for the NA61/SHINE at CERN SPS and the CBM at FAIR, and Zero Degree Calorimeter (ZDC) for the MPD at NICA are discussed. The PSDs and ZDC are compensating lead-scintillator calorimeters designed to measure the energy distribution of the forward going projectile nucleons and nuclei fragments (spectators) produced close to the beam rapidity. Design of the PSD modules, their readout electronics, and calirmeter performance for the collision centrality and reaction plane determination are presented. The PSD module tests with different beams at CERN SPS and results of radiation hardness tests of the avalanche photodiodes used for light readout from the PSD module are also reported.

Radiation hardness tests of Avalanche Photodiodes for FAIR, NICA, and CERN SPS experiments

Modern avalanche photodiodes with high gain are excellent device candidates for the light readout from detectors used for the high energy physics experiments. We report the results of the APDs radiation hardness study. Properties of APDs manufactured by Ketek and Hamamatsu companies has been studied in terms of internal defects accumulation. Test setups for offline and online APD irradiation measurements are described. Simplified models estimating contribution of various noise components are discussed in comparison with data achieved by static and dynamic characteristics analysis. The results of the APDs investigations after irradiation using secondary neutrons from the cyclotron facility U120M at the Nuclear Physics Institute of CAS in Řež are presented.

Setup for laboratory studies of the environmental conditions influence on the fixed charge state in silicon dioxide

The position sensitive detectors operate in high intensity radiation field of the collider experiment [1]. Important task is to estimate the influence of different radiation effects on properties of the detector. We focus on the laboratory studies to estimate the reliability of different types of silicon detectors. We use the simple test structures produced by standard technology for the silicon detectors. We give the primary attention to the case when the depth of active detector region varies from 10 to 20 μ m because it leads to the most significant influence of SiO2-Si interface on processes in silicon bulk. We present the experimental results of long term irradiation test with Am241 (one year). Influence of the environmental conditions on the fixed charge states in silicon dioxide was investigated using developed simple model.