arXiv subjects

Johann Marton

Publications and source records attributed to Johann Marton.

21 records · Page 2Linked to original sources

arXiv2010

Application of Geiger-mode photo sensors in Cherenkov detectors

Silicon-based photosensors (SiPMs) working in the Geiger-mode represent an elegant solution for the readout of particle detectors working at low-light levels like Cherenkov detectors. Especially the insensitivity to magnetic fields makes this kind of sensors suitable for modern detector systems in subatomic physics which are usually employing magnets for momentum resolution. In our institute we are characterizing SiPMs of different manufacturers for selecting sensors and finding optimum operating conditions for given applications. Recently we designed and built a light concentrator prototype with 8x8 cells to increase the active photon detection area of an 8x8 SiPM (Hamamatsu MPPC S10931-100P) array. Monte Carlo studies, measurements of the collection efficiency, and tests with the MPPC were carried out. The status of these developments are presented.

physics.ins-det↗

arXiv2010

Silicon photomultiplier timing performance study

Many characteristics of Silicon Photomultipliers can be tuned with temperature and operation voltage. We present preliminary results of a study of the effect of these two operation parameters on the time resolution of large active area Multi-Pixel Photon Counters (MPPCs) manufactured by Hamamatsu. Measurements at -10 C, 0 C, and 10 C at different bias voltages were performed. The time resolution is best at low temperature and high over-voltage. Most significant improvements can be achieved in cases with low number of fired pixels (<10 pixels). Between the worst and best case among the considered conditions a factor of 5 improvement was observed. In cases with large number of fired pixels (>40 pixels) the effect of temperature and operation voltage becomes smaller. The timing performance still improves with decreasing temperature (~ factor of 2) but it hardly depends on the operation voltage. The study shows, that especially in applications where only few photons are available for detection a careful optimization of temperature and operation voltage are advisable to obtain optimum timing results with the MPPC.

physics.ins-det↗

arXiv2009

Development of a GEM-TPC prototype

The use of GEM foils for the amplification stage of a TPC instead of a con- ventional MWPC allows one to bypass the necessity of gating, as the backdrift is suppressed thanks to the asymmetric field configuration. This way, a novel continuously running TPC, which represents one option for the PANDA central tracker, can be realized. A medium sized prototype with a diameter of 300 mm and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector test under realistic experimental conditions should allow us to verify the spatial resolution for single tracks and the reconstruction capability for displaced vertexes. A series of physics measurement implying pion beams is scheduled with the FOPI spectrometer together with the GEM-TPC as well.

physics.ins-det↗