Design characteristics and first experience concerning the new high-resolution powder diffractometer for thermal neutrons at the Swiss spallation neutron source SINQ are summarized. It is based on a ...linear position-sensitive
3
He
detector with 1600 wires and angular separation of 0.1°, permitting also real-time experiments.
A new data acquisition system (DAQ) for bulk
μ
SR and low-energy
μ
SR (LE-
μ
SR) has been developed at PSI. It is based on commercial and in-house VME modules, and on the MIDAS DAQ software library. ...The system is able to cope with the different needs of the various PSI
μ
SR spectrometers, which was not possible with the existing CAMAC and ORTEC's pTA-clock based DAQ systems. The VME clock is a 64-channel CAEN V1190 TDC, using the CERN HPTDC chip, with programmable time resolution of 25, 100, 200 or 800
ps. The TDC onboard memory is continuously read through the VME bus by standard PC's or dedicated servers, using a 1-Gbit/s SIS3100/1100 VME–PCI interface. Detector rates are independently monitored using a 32-channel SIS3820 scaler module. In-house developed modules comprise an 8-channel constant fraction discriminator CFD950, a CD950 clock divider, an 8-channel linear fan-out SP950, a 16-channel NIM-ECL level converter LC950, and a programmable coincidence module FC950. All modules feature a superior performance compared to commercially available devices which allows their use also in the planned high-field
μ
SR spectrometer where a time resolution of about 100
ps is envisaged. A special external hardware logic is no longer required, since the system can deal with a rate total of 5
MHz which is sufficient for
μ
SR spectrometers with high event rate in their active veto systems.
Two very promising materials as the BrilLanCe (Cerium doped Lanthanum Bromide, LaBr3(Ce) and the LYSO (Lutetium Yttrium OxyorthoSilicate, Lu2(1−x) Y2x SiO5 (Ce)) coupled to Silicon photomultipliers ...(MPPC/SiPM) could represent an appealing option for the future calorimetry. The response of both LaBr3(Ce) and LYSO detectors having MPPC as photosensors have been studied via detailed Monte Carlo (MC) simulations. The impinging gammas are in the range of 50–100 MeV. The MC simulations are based on GEANT4, including the full electronic chain up to the waveform digitizer and finally the reconstruction algorithms.
The results have been obtained are very promising. For a detector based on a (radius R = 4.45 cm, length L = 20.3 cm) LaBr3(Ce) crystal an energy resolution of σE/E%=2.3(1) and a timing resolution of σtps = 35(1) have been predicted. The energy resolution can be further improved by using larger crystals (either R = 6.35 cm or R = 7.6 cm, L = 20.3 cm) approaching respectively a σE/E%=1.20(3) or a σE/E%=0.91(1). Detector based on LYSO crystal of similar size performs even better, thanks to the shorter LYSO Moliere radius compared to the LaBr3(Ce) one. For a detector based on a (R = 3.5 cm, L = 16 cm) LYSO crystal an energy resolution of σE/E%=1.7(1)% can be obtained, and that can be further improved using bigger crystals (R = 6.5 cm, L = 25 cm, σE/E%=0.74(1)%. Energy resolution approaching σE/E%=0.3(1)% can be addressed for both crystals with ultimate sizes (R = 20–23 cm, L = 17–32 cm), complemented by timing and position resolutions in the range of O(30) ps and O(a few mm) respectively. Such results put these future high energy calorimeters at the detector forefront at intensity frontiers.
A scalable 16-ch thermal neutron detection system has been developed in the framework of the upgrade of a neutron diffractometer. The detector is based on a ZnS:6LiF scintillator with embedded WLS ...fibers which are read out with SiPMs. In this paper, we present the 16-ch module, the dedicated readout electronics, a direct comparison between the performance of the diffractometer obtained with the current 3He detector and with the 16-ch detection module, and the channel-to-channel uniformity.
We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS ...fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.
•Application of digital signal processing for a SiPM-based ZnS:6LiF neutron detector.•Optimisation of detector performances with 3 different digital filters.•Comparison with detector performances with a full analog signal processing.
In this paper we present the development of a one-dimensional multi-channel thermal neutron detection system for the application in neutron scattering instrumentation, e.g. strain-scanning ...diffractometers. The detection system is based on ZnS(Ag):6LiF neutron scintillator with embedded WLS fibers which are read out with a SiPM. A dedicated signal processing system allows us to suppress the SiPM dark counts and to extract the signals from the neutron absorption events.
For a single-channel detection unit which represents the elementary building block of this detection system we achieved a neutron detection efficiency of ~65% at 1.2Å, a background count rate <10−3Hz and a gamma-sensitivity <10−6 (measured with a 60Co source), while the dead time is ~20μs and the multi-count ratio is <1%. This performance was achieved even for SiPM dark count rates of up to ~2MHz.
In this paper we present the development of a one-dimensional multi-channel thermal neutron detection system for the application in neutron scattering instrumentation, e.g. strain-scanning ...diffractometers. The detection system is based on ZnS(Ag): super(6)LiF neutron scintillator with embedded WLS fibers which are read out with a SiPM. A dedicated signal processing system allows us to suppress the SiPM dark counts and to extract the signals from the neutron absorption events. For a single-channel detection unit which represents the elementary building block of this detection system we achieved a neutron detection efficiency of ~65% at 1.2 Aa, a background count rate View the MathML source <10-3Hz and a gamma-sensitivity <10 super(-6)<10-6 (measured with a super(60)Co source), while the dead time is ~20 mu s and the multi-count ratio is <1%<1%. This performance was achieved even for SiPM dark count rates of up to ~2 MHz.
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