Multi-pixel Photon Counters Readout Research Articles

Time resolution and high-counting rate performance of plastic scintillation counter with multiple MPPC readout

We have been developing a plastic scintillation counter for the WASA detector. The performance of a plastic scintillation counter with Multi-Pixel Photon Counter (MPPC) readout has been systematically investigated for minimum ionizing particles in terms of the time resolution and the signal amplitude stability. The performance was evaluated under various incident conditions of 2.5 GeV/c proton beams and with different MPPC settings. A plastic scintillator with a size of 550×38×8mm3 was optically coupled with multiple MPPCs at each plane with a size of 38×8mm2 for detecting the scintillation photons. The observed time resolution ranges in 37–80 ps (σ) depending on the incident positions and angles for the case of three MPPCs attached to each end. We found the time resolution and the signal amplitude fairly consistent up to the counting rate of 0.2 MHz.

Performance Characterization of MPPC Modules for TOF-PET Applications

PET detectors commonly feature large numbers of multipixel photon counters (MPPCs), requiring data acquisition systems with significant signal multiplexing or using application specific integrated circuits (ASICs) for independent MPPC readout. We evaluate here two Hamamatsu C13500-4075LC-12 detector modules designed for time-of-flight (TOF) PET. Each module has a 12 $ {\times }$ 12 lutetium fine silicate crystal array (4.2 $ {\times }$ 4.2 $ {\times }$ 20 mm3) one-to-one coupled to a 12 $ {\times }$ 12 array of 4 mm MPPCs. Each detector has 8 18-channel ASICs utilizing time-over-threshold (ToT) readout. At low event rates, the detectors have full-width at half-maximum (FWHM) energy resolution of 11.8%±0.4%, measured in linearized energy spectra, and 275 ps FWHM coincidence timing resolution (CTR) using energy window of ±1 photopeak FWHM. The 511 keV photopeak amplitude in the ToT spectrum changed 0.24%/°C. There was <10% event loss up to 1450 kcps/detector. From count rates of 35–1450 kcps the 511 keV photopeak position varied by 1.2%, while photopeak FWHM in the ToT spectra increased by 54%, from 5.8% to 9.0%, corresponding to energy resolution changing from 11.8% to approximately 18.0%. Over this count rate range the CTR varied from 285 to 435 ps FWHM. The TOF-PET module performance suggests they are well suited to use in whole-body PET applications.

Performance study of a large CsI(Tl) scintillator with an MPPC readout for nanosatellites used to localize gamma-ray bursts

We are designing a fleet of nanosatellites to perform accurate position determinations of short-duration gamma-ray bursts by measuring arrival time differences. To achieve sufficient photon statistics to measure the arrival times precisely under the severe limitations of size, mass and power consumption, we propose the use of large-area CsI(Tl) scintillators which provide a high light output and the use of a small-sized multipixel photon counters (MPPC), a kind of SiPM, that have low power consumption. We plan to use one of the latest-model MPPCs provided by Hamamatsu Photonics, namely, S13360-6050CS, which has an active area of 6×6 mm2. We have compared the performance of two scintillators of different sizes (150×75×5 mm3 and 100×75×5 mm3); the bigger one is the maximum size that can be mounted on a three-unit satellite, according to CubeSat standards. We have found that the light yield of the bigger scintillator is lower than that of the smaller one, but the difference is only approximately 13%, and each has an energy threshold of ∼10 keV at 25∘C. We have tested one- and two-MPPC readout and confirmed the same energy thresholds. The light yield for the two-MPPC readout is 1.4 times as high as that for the one-MPPC readout. We have also examined the position dependence of the light yield by using radiation from a 241Am (59.5 keV) source, and confirmed that uniformity was improved, and energy resolution got better by ∼7% for two-MPPC readout.

Potential for reducing the numbers of SiPM readout surfaces of laser-processed X’tal cube PET detectors

We are developing a three-dimensional (3D) position-sensitive detector with isotropic spatial resolution, the X’tal cube. Originally, our design consisted of a crystal block for which all six surfaces were covered with arrays of multi-pixel photon counters (MPPCs). In this paper, we examined the feasibility of reducing the number of surfaces on which a MPPC array must be connected with the aim of reducing the complexity of the system. We evaluated two kinds of laser-processed X’tal cubes of 3 mm and 2 mm pitch segments while varying the numbers of the 4 × 4 MPPC arrays down to two surfaces. The sub-surface laser engraving technique was used to fabricate 3D grids into a monolithic crystal block. The 3D flood histograms were obtained by the Anger-type calculation. Two figures of merit, peak-to-valley ratios and distance-to-width ratios, were used to evaluate crystal identification performance. Clear separation was obtained even in the 2-surface configuration for the 3 mm X’tal cube, and the average peak-to-valley ratios and the distance-to-width ratios were 6.7 and 2.6, respectively. Meanwhile, in the 2 mm X’tal cube, the 6-surface configuration could separate all crystals and even the 2-surface case could also, but the flood histograms were relatively shrunk in the 2-surface case, especially on planes parallel to the sensitive surfaces. However, the minimum peak-to-valley ratio did not fall below 3.9. We concluded that reducing the numbers of MPPC readout surfaces was feasible for both the 3 mm and the 2 mm X’tal cubes.

The T2K Side Muon Range Detector (SMRD)

The T2K experiment is a long baseline neutrino oscillation experiment aiming to observe the appearance of νe in a νμ beam. The νμ beam is produced at the Japan Proton Accelerator Research Complex (J-PARC), observed with the 295km distant Super-Kamiokande Detector and monitored by a suite of near detectors at 280m from the proton target. The near detectors include a magnetized off-axis detector (ND280) which measures the unoscillated neutrino flux and neutrino cross-sections. The present paper describes the outermost component of ND280 which is a Side Muon Range Detector (SMRD) composed of scintillation counters with embedded wavelength shifting fibers and Multi-Pixel Photon Counter readout. The components, performance and response of the SMRD are presented.

Directly coupled tiles as elements of a scintillator calorimeter with MPPC readout

We present results on the direct, i.e. fiberless coupling of scintillator tiles to Multi-pixel Photon Counters (MPPC). The fiberless option has the potential of simplifying the assembly and construction of a finely segmented scintillator-based calorimeter with MPPC readout. In this paper we show detailed studies on the response and uniformity of directly coupled tiles and describe our concept for an integrated readout layer (IRL).

Fine Granular Calorimeter with Scintillator Strips and New Photon Sensor Readout

The Global Large Detector (GLD) is one of the detector concepts proposed for the future linear collider experiment. At the linear collider experiment Particle Flow Algorithm plays an important role in achieving excellent jet energy resolution (~30%/radicE). This method requires a finely segmented calorimeter able to separate individual particles inside jets in the calorimeter. The GLD calorimeter is a sampling calorimeter which consists of scintillator and absorber (tungsten for electromagnetic, lead or iron for hadron calorimeter) layers. It has a scintillator-strip structure; strips in successive scintillator layers are aligned in orthogonal directions to achieve effective 1 times cm2 segmentation. To read out the signal from all the individual scintillator strips, we adopt a new photon sensor, the Multi-Pixel Photon Counter (MPPC). The MPPC consists of 100-1600 APD pixels, each of which works in the limited Geiger mode. This new photon sensor has many excellent features (compact size, low cost, high gain and photon detection efficiency and insensitivity to magnetic fields) and is suitable for use in the GLD calorimeter readout. We have tested 800 samples of 1600-pixel MPPCs and confirmed that the performance is satisfactory for calorimetric use. We have also constructed an electromagnetic calorimeter test module with 468 scintillator strips and full MPPC readout, and performed a beam test using a 1-6 GeV positron beam to evaluate its performance. The test module was measured to have good performance (energy resolution is (13.45 plusmn 0.07)% / radicE oplus (2.87 plusmn 0.08)%, deviation from linearity is less than 4%), showing that the 1600-pixel MPPC is suitable for the readout of finely segmanted calorimeters.