V. A. Kaplin

Silicon photomultiplier and its possible applications

The Silicon Photomultiplier (SiPM) is a semiconductor device consisting of many photon microcounters (10 3 mm 2 ) positioned on a common Si substrate. SiPM operates in a limited Geiger mode and has single photoelectron gain (10 6 ) and photon detection efficiency (20%) similar to vacuum PMT. Main SiPM features are described and a number of examples of its possible applications are demonstrated, such as scintillator fiber readout, scintillator tiles+WLS readout, imaging Cherenkov counter timing. These SiPM applications are based on experimental test data and SiPM performance is compared with other photodetectors (PMT, APD, HPD, VLPC). r 2003 Elsevier Science B.V. All rights reserved.

Limited Geiger-mode microcell silicon photodiode: New results

Recent results on Limited Geiger-mode Microcell Silicon Photodiode (LGP) are described. Two new modications of LGP have been designed and produced. Each of them consists of 104 pixels 10]10 lm2 size with area of 1 mm2. These pixels operate as an independent photon counters, giving the output signal as a sum of the signals from pixels red by photons. The e!ective ‘gaina is large (+105). The e

THE ADVANCED STUDY OF SILICON PHOTOMULTIPLIER

ciency of the visible light photon detection of few percents has been measured. Low-temperature dark rate dependence has been studied. The timing by LGP at the level of 100 ps (FWHM) was found. ( 2000 Elsevier Science B.V. All rights reserved.

Design and performance of the GAMMA-400 gamma-ray telescope for dark matter searches

The advanced study of new photo detector Silicon Photomultiplier (SiPM) is presented. SiPM consists of many (∼103 mm−2) silicon micro pixels, which are independent photon micro counters working in limited Geiger mode with a gain of 106. The SiPM output signal is a sum of the signals from a number of pixels fired by photons. The main features of SiPM are: low excess noise factor, the photon detection efficiency at the level of vacuum PMT, low bias voltage (∼24V). The timing of the SiPM is about 30 ps for 10 photoelectrons. The possibilities of SiPM applications based on experimental tests are demonstrated: sci fiber readout, scintillator-shifter system readout, possible application for hadron calorimeters.

GAMMA-400 gamma-ray observatory

The GAMMA-400 gamma-ray telescope is designed to measure the fluxes of gamma-rays and cosmic-ray electrons + positrons, which can be produced by annihilation or decay of the dark matter particles, as well as to survey the celestial sphere in order to study point and extended sources of gamma-rays, measure energy spectra of Galactic and extragalactic diffuse gamma-ray emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400 covers the energy range from 100 MeV to 3000 GeV. Its angular resolution is ∼0.01° (Eγ > 100 GeV), the energy resolution ∼1% (Eγ > 10 GeV), and the proton rejection factor ∼106. GAMMA-400 will be installed on the Russian space platform Navigator. The beginning of observations is planned for 2018.

Observation of light emission from Hamamatsu R11410-20 photomultiplier tubes

The GAMMA-400 gamma-ray telescope with excellent angular and energy resolutions is designed to search for signatures of dark matter in the fluxes of gamma-ray emission and electrons + positrons. Precision investigations of gamma-ray emission from Galactic Center, Crab, Vela, Cygnus, Geminga, and other regions will be performed, as well as diffuse gamma-ray emission, along with measurements of high-energy electron + positron and nuclei fluxes. Furthermore, it will study gamma-ray bursts and gamma-ray emission from the Sun during periods of solar activity. The energy range of GAMMA-400 is expected to be from ~20 MeV up to TeV energies for gamma rays, up to 20 TeV for electrons + positrons, and up to 10E15 eV for cosmic-ray nuclei. For high-energy gamma rays with energy from 10 to 100 GeV, the GAMMA-400 angular resolution improves from 0.1{deg} to ~0.01{deg} and energy resolution from 3% to ~1%; the proton rejection factor is ~5x10E5. GAMMA-400 will be installed onboard the Russian space observatory.

RED-100 detector for the first observation of the elastic coherent neutrino scattering off xenon nuclei

Abstract We have shown that high voltage biased Hamamatsu R11410-20 photomultipliers with a dark count rate above 10xa0kHz emit single photons. The effect has been observed in a few units at room temperature and temperatures reduced down to −60xa0°C. The effect should be taken into account in experiments aimed on search for rare events with small energy depositions in massive liquid xenon detectors.

Noise characteristics of low-background Hamamatsu R11410-20 photomultiplier tubes

The RED-100 (Russian Emission Detector) is being constructed for the experiment to search for elastic coherent neutrino scattering off atomic nuclei. This fundamental process was predicted several decades ago by the Standard Model of electroweak interactions but has not been discovered yet. The RED-100 is a two-phase emission xenon detector containing ~200 kg of the liquid Xe (~ 100 kg of that is in a fiducial volume). One of the possible sites to carry out the experiment is the SNS (Spallation Neutron Source) facility at Oak Ridge National Laboratory, USA. SNS is the worlds most intense pulsed source of neutrinos and unique place to study neutrino properties. The energy spectrum of neutrinos produced at the SNS extends up to ~ 50 MeV and satisfies coherence condition. These neutrinos give kinetic energies of Xe recoils up to a few tens of keV where the response of nuclear recoils is well-known from neutron calibrations of dark matter detectors. The detector will be deployed in the basement under the experimental hall at a distance of ~30 meters from the SNS target. The expected signal and background (neutron and gamma) are estimated for this specific location. The detector details, current status and future plans are provided.

A controllable voltage divider for Hamamatsu R11410-20 photomultipliers for use in the RED 100 emission detector

The RED-100 two-phase liquid xenon emission detector is developed today for the experiment aimed at searching for elastic coherent neutrino scattering off atomic nuclei. The main elements of the photodetector system of the RED-100 detector are Hamamatsu R11410-20 photomultiplier tubes (PMTs) dedicated for low-background experiments and liquid xenon environment. The basic characteristics of the PMTs are investigated, in particular, noise pulses and afterpulses, which may cause difficulties in searching for rare events. Amplitude distributions of the noise pulses and time distributions of the afterpulses, as well as the dependences of the noise pulse rate on the PMT bias voltage and the temperature are presented.

The RED-100 two-phase emission detector

A control circuit for the operation of Hamamatsu R11410-20 photomultiplier tubes (PMTs), which is intended for use in the RED 100 liquid-xenon emission detector, was developed. To prevent the photocathode degradation due to intense flashes that are associated with signals from high-energy cosmic-ray muons, the circuit forms a voltage pulse that is fed to the PMT photocathode and “blocks” the interelectrode gap between the photocathode and the first dynode. Thus, electron current through this gap is stopped for some time, which suffices for the complete collection of ionization electrons in the RED 100 detector after a cosmic muon passes its sensitive volume. The parameters of the circuit are selected such that the PMT relaxation time after the termination of a blocking pulse, which is determined by the transient processes in the divider, is ∼200 μs for a divider with a total resistance of 20 MΩ. This is acceptable for the intended application of the RED 100 detector in an experiment on the search for coherent neutrino scattering off xenon nuclei.