Cryogenic phonon-scintillation detectors (CPSD) for rare event search experiments require reliable, efficient and robust photon detectors that can resolve individual photons in a scintillation event.
A particle detection system that exploits the scintillation light produced by ionizing particles in liquid argon (LAr) has been assembled at CERN. The system is based on 10 large-area photomultiplier tubes (PMT) immersed in a 1500-liter dewar filled with liquid argon and equipped with an extendible feed-through and mechanical support for an alpha source (241Am). The position of the source can be changed with respect to the PMT plane in vertical and horizontal directions. Arrays of silicon photomultiplier (SiPM) photodetectors, integrated in the source support, are used for the data acquisition…
The CAEN V1751 is a new generation of Waveform Digitizer recently introduced by CAEN SpA. It features 8 Channels per board, 10 bit, 1 GS/s using Flash ADCs Waveform Digitizers (or 4 channels at 2 GS/s in Dual Edge Sampling mode) with threshold and Auto-Trigger capabilities. This provides a good basis for data acquisition in Dark Matter searches using PMTs to detect scintillation light in liquid argon, as it matches the requirements for measuring the fast scintillation component. The board was tested by operating it in real experimental conditions and by comparing it with a state of the art dig…
We report the results of a characterization study of several types of cryogenic photomultipliers manufactured by Hamamatsu Photonics and intended for operation in liquid Ar conditions, namely: compact 2-inch R6041-506MOD tubes, 3-inch R11065-10 and R11065-MOD tubes for operation in liquid Ar and 3-inch R11410-20 tubes originally designed for operation in liquid Xe. These types of PMT are proposed for installation into the future two-phase cryogenic avalanche detector that is developed in the Laboratory of Cosmology and Particle Physics of the Novosibirsk State University jointly with the Budke…
GRANDProto35 is the first stage of the GRAND project. It will be composed of an array of 35 radio antennas and 24 scintillation detectors, the radio and scintillating subarrays being triggered independently. The scintillation detector array allow to cross check,through an offline treatment, if the selected radio candidates are indeed air shower events and thus quantitatively determine the detection efficiency of the radio array. The Hamamatsu R7725 is candidate for the scintillation detector photomultiplier. The characteristics of the PMT will directly affects the time and energy resolution, d…
We have investigated the possibility of calibrating the PMTs of scintillation detectors, using the primary scintillation produced by X-rays to induce single photoelectron response of the PMT. The high-energy tail of this response, can be approximated to an exponential function, under some conditions. In these cases, it is possible to determine the average gain for each PMT biasing voltage from the inverse of the exponent of the exponential fit to the tail, which can be done even if the background and/or noise cover-up most of the distribution. We have compared our results with those obtained b…
Simulation Based Characterization of Deconvolution-Based PMT Waveform Reconstruction Under Large Charge Dynamic Range and Varying Scintillation Time Profiles
School of Physical Science and Technology, Guangxi University(广西大学物理科学与技术学院)
New Cryogenic Avalanche Detector (CRAD) with ultimate sensitivity, that will be able to detect one primary electron released in the cryogenic liquid, is under development in the Laboratory of Cosmology and Particle Physics of the Novosibirsk State University jointly with the Budker Institute of Nuclear Physics. The CRAD will use two sets of cryogenic PMTs in order to get trigger signal either from primary scintillations in liquid Ar or from secondary scintillations in high field gap above the liquid. Two types of cryogenic PMTs produced by Hamamatsu Photonics were tested and the results are pr…
Silicon photomultipliers (SiPMs) are a good alternative to photomultiplier tubes (PMTs) because their gain and quantum efficiency are comparable to PMTs. However, the largest single-chip SiPM is still less than 1~cm$^2$. In order to use SiPMs with scintillators that have reasonable sensitivity, it is necessary to use multiple SiPMs. In this work, scintillation detectors are constructed and tested with a custom 2x2 SiPM array. The layout of the SiPMs and the geometry of the scintillator were determined by performing Geant4 simulations. Cubic NaI, CsI, and CLYC with 18~mm sides have been tested.…
The Hamamatsu R5912-02Mod photomultiplier tube (PMT) will be used in the DUNE dual-phase module, a 10-kton fiducial volume liquid-argon time-projection chamber, which is one of the four projected far-detector modules of the DUNE long-baseline neutrino experiment. In the DUNE dual-phase module, the liquid argon places high pressure on the photo-detectors located at the bottom of the 14-m cryostat. Four Hamamatsu R5912-02Mod PMTs were tested at 4-bar absolute pressure and cryogenic temperature (in liquid nitrogen) for the first time. No mechanical or electrical damage is reported, validating the…
In this work we present an elegant solution for a scintillation counter to be integrated into a cryogenic system. Its distinguishing feature is the absence of a continuous light guide coupling the scintillation and the photodetector parts, operating at cryogenic and room temperatures respectively. The prototype detector consists of a plastic scintillator with glued-in wavelength-shifting fiber located inside a cryostat, a Geiger-mode Avalanche Photodiode (G-APD) outside the cryostat, and a lens system guiding the scintillation light re-emitted by the fiber to the G-APD through optical windows …
We present the precision calibration of 35 Hamamatsu R11410-22 photomultiplier tubes (PMTs) with xenon scintillation light centred near 175 nm. This particular PMT variant was developed specifically for the LUX-ZEPLIN (LZ) dark matter experiment. A room-temperature xenon scintillation cell coupled to a vacuum cryostat was used to study the full-face PMT response at both room and low temperature $\textrm{($\sim$ -100$^\circ$C)}$, in particular to determine the quantum efficiency (QE) and double photoelectron emission (DPE) probability in LZ operating conditions. For our sample with an average Q…
The MicroBooNE detector, to be located on axis in the Booster Neutrino Beamline (BNB) at the Fermi National Accelerator Laboratory (Fermilab), consists of two main components: a large liquid argon time projection chamber (LArTPC), and a light collection system. Thirty 8-inch diameter Hamamatsu R5912-02mod cryogenic photomultiplier tubes (PMTs) will detect the scintillation light generated in the liquid argon (LAr). This article first describes the MicroBooNE PMT performance test procedures, including how the light collection system functions in the detector, and the design of the PMT base. The…
We have studied the scintillation of pure and doped sodium iodide crystals handled in low humidity conditions under external $α$ and $γ$ excitation from room temperature down to 4K. The light yield of pure sodium iodide was seen to increase at low temperatures by a factor 30 compared to room temperature, up to a maximum of 40 photons/keV under $γ$ excitation at 60K, stabilizing to 30 photons/keV at lower temperatures. Thallium doped sodium iodide fluctuates by 20% around the room temperature value, stabilizing at 40 photons/keV at low temperature. $α/ γ$ quenching factor stabilizes at roughly …
The Deep Underground Neutrino Experiment (DUNE) is a dual-site experiment for long baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches. The far detector is a 40-kton underground liquid argon time-projection-chamber (LAr TPC), in which the photon detector system adds precise timing capabilities. The ProtoDUNE dual phase detector will consist of a 6x6x6 m^3 LAr TPC to be operated at the CERN Neutrino Platform and the photon detection system will be formed by 8-inch cryogenic photomultipliers from Hamamatsu. The PMT model (R5912-20Mod) performance at cr…
The high scintillation luminosity of n-type GaAs at 10K is surprising because (1) with a refractive index of about 3.5, escape is inhibited by total internal reflection and (2) narrow-beam experiments at 90K report infrared absorption coefficients of several per cm. This paper presents Monte Carlo calculations showing that the high luminosity at 10K can be explained if (1) narrow-beam absorption is almost all optical scattering and (2) the absolute absorption coefficient is below 0.1 per cm. Sixteen surface reflector configurations are simulated for a range of internal scattering and absolute …
Presented here are first tests of a Gaseous Photomultiplier based on a cascade of Thick GEM structures intended for gamma-ray position reconstruction in liquid Argon. The detector has a MgF$_2$ window, transparent to VUV light, and a CsI photocathode deposited on the first THGEM. A gain of $8\cdot10^{5}$ per photoelectron and $\sim100\%$ photoelectron collection efficiency are measured at stable operation settings. The excellent position resolution capabilities of the detector (better than 100 $μ$m) at 100 kHz readout rate, is demonstrated at room temperature. Structural integrity tests of the…
In this paper we report on measurements of the effects of dissolved methane upon argon scintillation light. We monitor the light yield from an alpha source held 20 cm from a cryogenic photomultiplier tube (PMT) assembly as methane is injected into a high-purity liquid argon volume. We observe significant suppression of the scintillation light yield by dissolved methane at the 10 part per billion (ppb) level. By examining the late scintillation light time constant, we determine that this loss is caused by an absorption process and also see some evidence of methane-induced scintillation quenchin…
This paper presents the proposed PMT readout and triggering system that will be used in the MicroBooNE LArTPC experiment. The triggering scheme has been designed to study beam neutrino events as well as fully characterize cosmic rays. In addition, exploration of important physics applications including "late" scintillation light in argon and Michel electrons from muon decay will be possible. Various types of triggers and how they will be implemented in the combined PMT+TPC readout electronics system will be discussed.
High light collection efficiency is an important requirement in any application of scintillation detectors. The purpose of this study is to investigate the possibility for improving this parameter in cryogenic scintillation bolometers, which can be considered as a promising detectors in experiments investigating neutrinoless double beta decay and dark matter. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO4 scintillation crystals of different shapes (cylinder 20 mm in dimater by 20 mm and hexagonal prism with diagonal 20 mm and height 20 mm), reflector ma…
Simulations of photon propagation in scintillation detectors were performed with the aim to find the optimal scintillator geometry, surface treatment, and shape of external reflector in order to achieve maximum light collection efficiency for detector configurations that avoid direct optical coupling, a situation that is commonly found in cryogenic scintillating bolometers in experimental searches for double beta decay and dark matter. To evaluate the light collection efficiency of various geometrical configurations we used the ZEMAX ray-tracing software. It was found that scintillators in the…
Caesium iodide is one of the more extensively studied scintillators. Here we present X-ray luminescence spectra, scintillation light output and decay curves as function of temperature, from room temperature down to below 10 K. Features of the observed intrinsic luminescence are explained in terms of radiative recombination of on- and off-centre STE. A model permitting interpretation of the dynamics of luminescence changes in CsI with temperature is suggested. This model includes adiabatic potential energy surfaces (APES) associated with singlet and triplet states of self-trapped excitons (STE)…
This paper is the first report of n-type GaAs as a cryogenic scintillation radiation detector for the detection of electron recoils from interacting dark matter (DM) particles in the poorly explored MeV/c2 mass range. Seven GaAs samples from two commercial suppliers and with different silicon and boron concentrations were studied for their low temperature optical and scintillation properties. All samples are n-type even at low temperatures and exhibit emission between silicon donors and boron acceptors that peaks at 1.33 eV (930 nm). The lowest excitation band peaks at 1.44 eV (860 nm) and the…
For future MeV-scale neutrino experiments, a Cherenkov scintillation detector, CSD, is of particular interest for its capability to reconstruct both energy and direction for charged particles. A type of new target material, slow liquid scintillator, SlowLS, which can be used to separate Cherenkov and scintillation lights, is one of the options for the neutrino detectors. A multi-hundred ton spherical CSD is simulated using a Geant4-based Monte Carlo software, which handles the detailed the micro processes of MeV particles and optical photons and the functions for photomultiplier, PMT, and read…
Scintillation at cryogenic temperatures can give rise to detectors with particle discrimination for rare-event searches such as dark matter detection. We present time-resolved scintillation studies of Caesium Iodide (CsI) under excitation of both alpha and gamma particles over a long acquisition window of 1 ms to fully capture the scintillation decay between room temperature and 4 K. This allows a measurement of the light yield independent of any shaping time of the pulse. We find the light yield of CsI to increase up to two orders of magnitude from that of room temperature at cryogenic temper…
The properties of large volume cylindrical 3.5 x 8 inches (89 mm x 203 mm) LaBr3:Ce scintillation detectors coupled to the Hamamatsu R10233-100SEL photo-multiplier tube were investigated. These crystals are among the largest ones ever produced and still need to be fully characterized to determine how these detectors can be utilized and in which applications. We tested the detectors using monochromatic gamma-ray sources and in-beam reactions producing gamma rays up to 22.6 MeV; we acquired PMT signal pulses and calculated detector energy resolution and response linearity as a function of gamma-…
The bright scintillation of pure CsI operated at liquid-nitrogen temperature makes of this material a promising dark matter and neutrino detector. We present the first measurement of its quenching factor for nuclear recoils. Our findings indicate it is indistinguishable from that for sodium-doped CsI at room temperature. Additional properties such as light yield, afterglow, scintillation decay properties for electron and nuclear recoils, and energy proportionality are studied over the \mbox{108-165 K} temperature range, confirming the vast potential of this medium for rare-event searches.
Characteristic properties of a Geiger Mode APD (G-APD) in a THGEM-based cryogenic two-phase Ar avalanche detector were studied in view of potential applications in rare-event experiments. G-APD signal amplitude and noise characteristics at cryogenic temperatures turned out to be superior to those at room temperature. The effective detection of avalanche scintillations from THGEM-multiplier holes in two-phase Ar has been demonstrated using a G-APD without wavelength shifter. At an avalanche gain of 60, the avalanche scintillation yield measured by the G-APD was as high as 0.9 photoelectrons per…
The construction of large-scale liquid scintillator detectors is complicated by the need to separate the scintillation region from photomultiplier tubes (PMTs) due to their intrinsic radioactivity. This is generally done using acrylic or nylon barriers, whose own activity can also lead to substantial reduction of the fiducial detection volume for a number of low energy (MeV) studies, and whose construction becomes increasingly difficult and expensive for larger detector volumes. Here we present an initial simulation study of an alternative geometric construction known as SLIPS (Stratified LIqu…
A two-phase Cryogenic Avalanche Detector (CRAD) with electroluminescence (EL) gap, operated in argon doped with a minor (49$\pm$7 ppm) admixture of nitrogen, has been studied. The EL gap was optically read out using cryogenic PMTs located on the perimeter of the gap. We present the results of the measurements of the N$_2$ content, detector sensitivity to X-ray-induced signals, EL gap yield and electron lifetime in the liquid. The detector sensitivity, at a drift field in liquid Ar of 0.6 kV/cm, was measured to be 9 and 16 photoelectrons recorded at the PMTs per keV of deposited energy at 23 an…
ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber (LArTPC) operated at the Neutrino Platform at CERN in 2019-2020 as a prototype of the DUNE Far Detector. DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. The light signal in these detectors is crucial to provide precise timing capabilities. In ProtoDUNE-DP, scintillation light produced by cosmic muons inthe LArTPC is collected by the photomultiplier tubes (PMTs) placed up to 7 m away from the point of interaction. The scintillation light production and…
Scintillation response of cryogenic CsI to few-keV and sub-keV nuclear recoils
University of Chicago(芝加哥大学);Donostia International Physics Center (DIPC)(多诺西亚国际物理中心);Ikerbasque, Basque Foundation for Science(伊克尔巴斯基克,巴斯克科学基金会);Instituto de Física Corpuscular, CSIC & Universitat de València(粒子物理研究所,西班牙国家科学研究委员会与瓦伦西亚大学)
Many current and future dark matter and neutrino detectors are designed to measure scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on the ability to accurately identify individual photoelectrons in PMT waveforms despite large variability in pulse amplitudes and pulse pileup. We describe a Bayesian technique that can identify the times of individual photoelectrons in a sampled PMT waveform without deconvolution, even when pileup is present. To demonstrate the technique, we ap…
In prospect of its application in cryogenic rare-event searches, we have investigated the low-temperature scintillation properties of CaWO4 crystals down to 3.4 K under α and γ excitation. Concerning the scintillation decay times, we observe a long component in the ms range which significantly contributes to the light yield below 40K. For the first time we have measured the temperature dependence of the α/γ- ratio of the light yield. This parameter which can be used to discriminate α and γ events in scintillating bolometers is found to be about 8-15% smaller at low temperatures compared to roo…
Optimization of the light detection system of the ICARUS detector
INAF-OACT(国家天体物理研究所光学天文台);INFN, Sezione di Catania(意大利国家核物理研究院卡塔尼亚分部);Università degli Studi di Catania(卡塔尼亚大学);INFN, Sezione di Pavia(意大利国家核物理研究院帕维亚分部)
In low background and low threshold particle astrophysics experiments using observation of Cherenkov or scintillation light it is common to use pairs or arrays of photomultipliers operated in coincidence. In such circumstances, for instance in dark matter and neutrino experiments, unexpected PMT noise events have been observed, probably arising from generation of light from one PMT being detected by one or more other PMTs. We describe here experimental investigation of such coincident noise events and development of new techniques to remove them using novel pulse shape discrimination procedure…
Detection of scintillation light can play several important roles in LArTPCs. Increased collection efficiency could result in the improvement of time, energy, and position resolution. The SBND collaboration is developing detailed MC simulations to study the performance of different types of light systems in the LArSoft framework. Due to the vast number of photons typically produced in neutrino physics events, a full optical simulation becomes extremely hard to run on reasonable time scales. I will describe how the SBND simulation tackles these problems and its current status for two of the lig…
We have developed a detector, consisting of a cryogenic calorimeter with a scintillating crystal as absorber, and a second calorimeter for the detection of the scintillation light, both operated at 12 mK. Using a CaWO4 crystal with a mass of 6g as scintillating absorber, we have achieved a discrimination of nuclear recoils against electron recoils with a suppression factor of 99.7% at energies above 15 keV. This novel method will be applied for background rejection in the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) experiment looking for dark matter Weakly Interactin…
Detection of light signals is crucial to a wide range of particle detectors. In particular, efficient detection of vacuum ultraviolet (VUV) light will provide new opportunities for some novel detectors currently being developed, but is technically challenging. In this article, we characterized the performance of Hamamatsu VUV4 silicon photomultipliers (SiPMs) for detecting VUV argon scintillation light without wavelength shifting. Using a customized cryogenic amplifier design, we operated two models of VUV4 SiPMs inside liquid argon and thoroughly examined their direct sensitivities to liquid …
A 760 $\times$ 760 $\times$ 30 mm$^3$ plastic scintillation detector viewed by photomultiplier tubes (PMTs) from four corners has been developed, and the detector has been tested with cosmic rays and $γ$ rays. A position-independent effective time T$_{eff}$ has been found, indicating this detector can be used as a TOF detector. The hit position can also be reconstructed by the time from four corners. A TOF resolution of 236 ps and a position resolution of 48 mm have been achieved, and the detection efficiency has also been investigated.
The JSNS$^{2}$ (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment aims to search for neutrino oscillations over a 24\,m short baseline at J-PARC. The JSNS$^{2}$ inner detector is filled with 17 tons of gadolinium-loaded liquid scintillator (LS) and both the intermediate $γ$-catcher and the optically separated outer veto are filled with un-loaded LS. Optical photons from scintillation are observed by 120 Photomultiplier Tubes (PMTs). A total of 130 PMTs for the JSNS2 experiment were both donated by other experiments and purchased from Hamamatsu. Donated PMTs were pu…
We present a detector apparatus, DireXeno (DIRectinal Xenon), designed to measure the spatial and temporal properties of scintillation in liquid xenon to very high accuracy. The properties of scintillation are of primary importance for dark matter and neutrinoless double beta decay experiments, however the complicated microphysics involved limits theoretical predictions. We will explore the possibility that scintillation emission exhibits correlation in light emission such as super-radiance, which depends on the type of interaction. Such properties of scintillation light may open a new window …
It was found that at cryogenic temperatures the spontaneous emission of single electrons from cathode of PMT is increased by lowering the temperature of PMT. This effect has not found yet a satisfactory explanation. It was suggested by us that the source of cryogenic dark current is a conversion of hidden photons on a metallic surface. To check this hypothesis a series of measurements have been performed using a multicathode counter developed by us as a detector of single electrons. Upon the results of measurements during 78 days in configurations R1 and R2 of a multicathode counter with a cop…
We discuss recent advances in the development of cryogenic gaseous photomultipliers (GPM), for possible use in dark matter and other rare-event searches using noble-liquid targets. We present results from a 10 cm diameter GPM coupled to a dual-phase liquid xenon (LXe) TPC, demonstrating - for the first time - the feasibility of recording both primary ("S1") and secondary ("S2") scintillation signals. The detector comprised a triple Thick Gas Electron Multiplier (THGEM) structure with cesium iodide photocathode on the first element; it was shown to operate stably at 180 K with gains above 10^5,…
DEAP-3600 is a liquid-argon scintillation detector looking for dark matter. Scintillation events in the liquid argon (LAr) are registered by 255 photomultiplier tubes (PMTs), and pulseshape discrimination (PSD) is used to suppress electromagnetic background events. The excellent PSD performance of LAr makes it a viable target for dark matter searches, and the LAr scintillation pulseshape discussed here is the basis of PSD. The observed pulseshape is a combination of LAr scintillation physics with detector effects. We present a model for the pulseshape of electromagnetic background events in th…
The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose neutrino experiment designed to measure the neutrino mass hierarchy using a central detector (CD), which contains 20 kton liquid scintillator (LS) surrounded by about 17,000 photomultiplier tubes (PMTs). Due to the large fiducial volume and huge number of PMTs, the simulation of a muon particle passing through the CD with the Geant4 toolkit becomes an extremely computation-intensive task. This paper presents a fast simulation implementation using a so-called voxel method: for scintillation photons generated in a certain LS…
A new type of the Multi-Pixel Photon Counter (MPPC), sensitive to Vacuum Ultra-Violet (VUV) light (wavelength λ < 150 nm), is recently developed and produced by Hamamatsu Photonics K.K. The basic properties of the new MPPC are measured at cryogenic facility of Waseda university using liquid nitrogen. Temperature dependence of breakdown voltage, capacitance, and dark count rate of the MPPC are also evaluated. In addition, the absolute photon detection efficiency (PDE) for liquid argon (LAr) scintillation light (λ = 128 nm) is estimated to be about 7% with uncertainty of 2% by using 241 Am α-ray…
Recently there is a flourishing and notable interest in the crystalline scintillator material sodium iodide (NaI) as target for direct dark matter searches. This is mainly driven by the long-reigning contradicting situation in the dark matter sector: the positive evidence for the detection of a dark matter modulation signal claimed by the DAMA/LIBRA collaboration is (under so-called standard assumptions) inconsistent with the null-results reported by most of the other direct dark matter experiments. We present the results of a first prototype detector using a new experimental approach in compa…
We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated gamma-ray source. Using the techniques described, the performance of the ZEPLIN-III dark matter detector was studied for 122 keV gamma-rays. For the inner part of the detector (R<100 mm), spatial resolutions of 13 mm and 1.6 mm FWHM were measured in the …
The China Dark Matter Experiment (CDEX) Collaboration will carry out a direct search for weakly interacting massive particles with germanium detectors. Liquid argon will be utilized as an anti-Compton and cooling material for the germanium detectors. A low-background and large-area photomultiplier tube (PMT) immersed in liquid argon will be used to read out the light signal from the argon. In this paper we carry out a careful evaluation on the performance of the PMT operating at both room and cryogenic temperatures. Based on the single photoelectron response model, the absolute gain and resolu…
We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that…