29th Symposium on Fusion Technology (SOFT 2016)

P3.045 Development of MPPC-based detectors for high count rate DT campaigns at JET

7 Sep 2016, 11:00

1h 20m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 45

Poster D. Diagnostics, Data Acquisition and Remote Participation P3 Poster session

Speaker

Andrzej Broslawski (Narodowe Centrum Badan Jadrowych)

Description

The products of fusion reactions at JET are measured using different diagnostic techniques. One of the methods is based on measurements of gamma-rays, originating from reactions between fast ions and plasma impurities. During the forthcoming deuterium-tritium (DT) campaign a particular attention will be paid to 4.44 MeV gamma-rays emitted in the ⁹9Be(α,nγ)¹²12C reaction. Gamma-ray detectors foreseen for measurements in DT campaigns have to register spectra at high count rates, up to approximately 1 MHz. For the Gamma-ray Camera at JET a new setup will be based on a CeBr3 or LaBr3 scintillator and a multi-pixel photon counter (MPPC). We present two methods of shortening output signals in modules based on MPPC. A short detector output signal is necessary in order to minimize the number of pile up events at high count rates. One method uses a passive RC circuit with a pole zero cancellation, whereas an active transimpedance amplifier is used in the other one. The stability of the peak position and energy resolution as a function of counting rate was measured with a ¹³⁷137Cs source. Due to the strong dependence of MPPC properties on temperature variation, a special device MTCD@NCBJ was designed and produced to stabilize the gain in MPPC-based scintillation detectors. We show that this device guarantees stable working conditions. This scientific work was partly supported by Polish Ministry of Science and Higher Education within the framework of the scientific financial resources in the years 2015-2017 allocated for the realization of the international co-financed project. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.