Aging experiments of a novel type of large area MCP-PMT made by JUNO collaboration were conducted.In these aging experiments, the multi-photoelectron spectrum and single photoelectron spectrum were measured daily,as well as the MCP resistance of the second PMT before and after the experiment. Two PMTs were aged successivelyfor cross check. The first PMT was aged for 52 days, while the other one was aged for 84 days. In order to study the mechanism of the aging process, the high voltage on the second PMT was increased to accelerate its aging process when the cumulative output of charge from its anode was about 4 C. From our study, it can be known that large area MCP-PMT aging had a strong relationship with the related MCPs. In accordance with the PMT aging curve,a PMT aging model was setup and a general aging formula was given.
The linearity of charge response is an important feature of photomultiplier tubes (PMT) for physics measurements, especially the newly developed 20" MCP-PMT. In this paper, in addition to the traditional method of double light sources, we applied another relative method of 20" PMT to 3" PMT to measure the linearity of the 20" dynode and MCP PMTs in pulse mode with a waveform digitizer. The measurements show a good linear response of 20" PMTs to 1,000 photoelectrons (p.e.). The correlations of the amplitude, rise-time, fall-time, FWHM, baseline recovery, overshoot, and late-pulse to the output …
JUNO is a 20-kton liquid scintillator detector aiming to determine the neutrino mass ordering, precisely measure the oscillation parameters, detect the astrophysical neutrinos and search for exotic physics. It is designed to reach an energy resolution of 3% at 1 MeV with the highest ever PMT coverage, using two types of 20 inch phototubes: MCP-PMT from NNVT and dynode-PMT from Hamamatsu. In this article, the gain and charge response of the MCP and dynode PMTs are investigated with the study of JUNO Central Detector prototype. The linearity of the MCP-PMT charge output is measured too to check …
The Jiangmen Underground Neutrino Observatory (JUNO) is proposed to determine the neutrino mass hierarchy using a 20 kiloton underground liquid scintillator detector (CD). One of the keys is the energy resolution of the CD to reach <3% at 1 MeV, where totally 15,000 MCP-PMT will be used. The optimization of the 20-inch MCP-PMT is very important for better detection efficiency and stable performance. In this work, we will show the study to optimize the MCP-PMT working configuration for charge measurement. Particularly, the quality of PMT signal is another key for high-precision neutrino experim…
The Argonne micro-channel plate photomultiplier tube (MCP-PMT) is an offshoot of the Large Area Pico-second Photo Detector (LAPPD) project, wherein \mbox{6 $\times$ 6 cm$^2$} sized detectors are made at Argonne National Laboratory. Measurements of the properties of these detectors, including gain, time and spatial resolution, dark count rates, cross-talk and sensitivity to magnetic fields are reported. In addition, possible applications of these devices in future neutrino and collider physics experiments are discussed.
The motivation of this paper is to explore the parameters that affect the performance of Microchannel Plate Photomultiplier Tubes (MCP-PMTs) in magnetic fields with the goal to guide their design to achieve a high magnetic field tolerance. MCP-PMTs based on two different designs were tested.The magnetic field tolerance of MCP-PMT based on a design providing independently biased voltages showed a significant improvement (up to 0.7 T) compared to the one utilizing an internal resistor chain design (up to 0.1 T), indicating the importance of individually adjustable voltages. The effects of the ro…
The Jiangmen Underground Neutrino Observatory (JUNO) will install about 18,000 20-inch Photomultiplier Tubes (PMTs) in the center detector to achieve 3%/sqrt(E(MeV)) energy resolution. From the full detector Monte Carlo (MC) simulation, besides the liquid scitillator (LS) and Acrylic nodes, PMT glass has the largest contribution to the natural radioactive background. Various technologies have been developed in the Chinese industry to control the environment and to improve the production process. We have monitored the glass production for more than two months, and the radioactivity in glass was…
We have developed a 4-channel multi-anode MCP-PMT, SL10, which exhibits a performance of sigma_TTS ~ 30 ps for single photons with G ~ 10^6 and QE=20% under a magnetic field of B <= 1.5 T. The cross-talk among anodes has been extensively studied. We have taken two measures to suppress it: one is to configure the SL10 to an effectively independent 4 small pieces of MCP-PMT's by segmenting an electrode of the second MCP-layer; the other is to use a constant fractional discriminator. Remarkable improvement has been achieved.
In order to develop a long-lifetime MCP-PMT under high rates of circumstance, we investigated the degradation of the quantum efficiency (QE) of PMT's with a multialkali photocathode. We found that not only positive ions, but also neutral residual gases would damage the photocathode resulting in an enhancement of the work function; their countermeasures were established in newly manufactured square-shaped MCP-PMT's with 4 or 4x4 multi-anodes. The performances of the PMT's were measured: QE was stable up to an integrated amount of anode output charge of 2-3 C/cm^2, while keeping other basic perf…
This paper reports on the time resolution of two photodetectors operated as single photon counters at high rate: a Hamamatsu R13742-103-M64 "conventional" (based on metal dynodes) multi-anode photomultiplier tube (MaPMT) and a Hamamatsu R10754-07-M16 microchannel plate photomultiplier tube (MCP-PMT). The MCP-PMT shows a time resolution (transit time spread, or jitter) of ~70 ps FWHM (~30 ps RMS) at low photon rates, but saturates above ~100 kHz/mm^2. The MaPMT can handle photon counting rates up to the highest tested, 10 MHz/mm^2. Its time resolution is ~250 ps FWHM (~110 ps RMS) when only the…
A first experimental test of tracking relativistic charged particles by `drifting' Cherenkov photons in a water-based optical time-projection chamber (OTPC) has been performed at the Fermilab Test Beam Facility. The prototype OTPC detector consists of a 77~cm long, 28~cm diameter, 40~kg cylindrical water mass instrumented with a combination of commercial $5.1\times5.1$~cm$^2$ micro-channel plate photo-multipliers (MCP-PMT) and $6.7\times6.7$~cm$^2$ mirrors. Five MCP-PMTs are installed in two columns along the OTPC cylinder in a small-angle stereo configuration. A mirror is mounted opposite eac…
We study the potential of the MCP-PMT read-out to detect single photo-electron using transmission lines. Such a solution limits the number of read-out channels, has a uniform time resolution across the PMT surface and provides quasi-continuous measurement of the spatial coordinates. The proposed solution is designed to be used in the BOLD-PET project aiming to develop an innovative detection module for the positron emission tomography using the liquid detection media, the tri-methyl bismuth. In this study we use the commercial MCP-PMT Planacon from Photonis, with 32x32 anode structure. The PCB…
We study the possibility to use the Cherenkov light for the efficient detection of 511 keV photons with the goal to use it in TOF-PET. We designed and tested two detection modules consisting of PbF$_2$ crystals attached to Planacon MCP-PMT XP85012. Amplified PMT signals are digitized by the SAMPIC module with high readout rate, up to $10^5$ events/s, and a negligible contribution to the time resolution, below 20 ps (FWHM). We developed a fast 2D scanning system to calibrate the PMT time response and studied in details the timing characteristics of the Planacon PMT. Using a radioactive $^{22}$N…
Multi Micro-Channel-Plate Photomultiplier tubes (MCP-PMT) with High Collection Efficiency (Hi-CE) MCPs are developed and characterised. With these Hi-CE MCPs more than 90% of photoelectrons emitted from the photocathode can be detected; this is in contrast to conventional MCPs where about 50% of photoelectrons are lost at the MCP stage. The drawback of the Hi-CE MCPs is a small degradation of the transfer time spread (TTS). However for applications where no sub-ns time resolution is required the implementation of Hi-CE MCPs is extremely beneficial, as it improves the detection efficiency of th…
The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r$<$5.5\,mm) the time resolution of the two MCP-PMTs combined is better than 10~ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial depe…
Development and characterization of hybrid MCP-PMT with embedded Timepix4 ASIC used as pixelated anode
INFN, Division of Ferrara（意大利国家核物理研究所费拉拉分部）；Dept. of Physics and Earth Science, University of Ferrara（费拉拉大学地球科学与物理学系）；EP Department, CERN（欧洲核子研究中心实验物理部）
The TORCH time-of-flight detector is designed to provide particle identification in the momentum range 2-10 GeV/c over large areas. The detector exploits prompt Cherenkov light produced by charged particles traversing a 10 mm thick quartz plate. The photons propagate via total internal reflection and are focused onto a detector plane comprising position-sensitive Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMT) detectors. The goal is to achieve a single-photon timing resolution of 70 ps, giving a timing precision of 15 ps per charged particle by combining the information from around 30 det…
High energy physics community is continuously working on development of new photodetectors able to improve their experiments detection performances and so to increase the possibility of new discoveries and new important scientific results. The first attempt to enhance the performances of classical PMTs by substituting the dynode chain is represented by MCP-PMTs. In addition to that, one of the strategies adopted to reach this goal is to realize hybrid photodetectors, that are new photomultipliers containing a semiconductor device within a vacuum tube. In the last years, basically three competi…
A prototype of DIRC-like Time-of-Flight detector (DTOF), including a pico-second time measurement electronics, is developed and tested preliminarily. The basic structure of DTOF is composed of a fused silica radiator connected to fast micro-channel plate PMTs (MCP-PMT), and readout by a dedicated FPGA (Field Programmable Gate Array) based front-end electronics. The full electronics chain consists of a programmable differential amplifier, a dual-threshold differential discriminator, and a timestamp Time-to-Digital convertor. By splitting a MCP-PMT output signal into two identical electronics ch…
