Search

The photomultiplier tube (PMT) and silicon photomultiplier (SiPM) of small areas have the characteristics of fast time response, suitable for the detection of fast and extremely weak light signals, and the transit time spread (TTS) can be on the picosecond scale. The test system is generally divided into two types: one is the direct acquisition of the waveform (DAW), (DAW such as the high-sampling oscilloscope), and the other is an indirect acquisition of the waveform (IDAW). In this article, both DAW and IDAW will be used to carry out the comparative test of ultra-fast photodetectors to complete the calibration of the performance of ultra-fast detectors and the study on time test systems. This will be helpful for beam experiments to be carried out in the laboratory and provide effective support for the development of domestic fast PMT. [ABSTRACT FROM AUTHOR]

The upgrade of the BESIII end cap time-of-flight (TOF) detector needs to achieve a ~40-ps time resolution level to provide high-performance reference time for beam testing. Fast silicon photomultiplier tubes (SiPMs) have excellent time characteristics and the transition time spread (TTS) can reach tens of picoseconds. Therefore, SiPMs are selected to replace the PMTs in T0 detectors. In this article, we describe that the time characteristics of a fast SiPM and T0 system were studied using a high-speed real-time oscilloscope. In order to obtain the optimal time resolution, coupling techniques of the plastic scintillators and SiPMs were studied. Single-ended coupling between a SiPM and a plastic scintillator can obtain the best time resolution. [ABSTRACT FROM AUTHOR]

In the past decade, a type of micro-channel-plate based photomultiplier tubes (MCP-PMT) with fast-timing resolution, also called fast-timing PMT(FPMT), has attracted considerable attention in many fields for its single-photon detection capability, good timing performance and magnetic insensitivity. The Silicon Photo-multiplier (SiPM) is another kind of newly developed photodetector with comparable performance to the FPMT. More attention was paid to the single photon time resolution of the photodetectors. However, with the improvement of the temporal performance requirements of photodetectors, the time resolution limit of photodetectors determine the limits of time performance improvement, which worth investigating. In this manuscript, a femtosecond laser is used to calibrate the time resolution limit of FPMT and SiPM. The time resolution limit of FPMT is measured to be 480.4 fs. In addition, the temporal performance of FPMT from single photon to multi-photons under femtosecond laser is also investigated. The time resolution limit of SiPM is measured to be 2.68 ps. • A femtosecond laser has been used for the first time to measure the time performance of ultrafast optoelectronic devices. • MCP-PMT achieves multi-photon time resolution on the femtosecond scale using femtosecond lasers. • The multiphoton time resolution of SiPM is less than 3 ps using femtosecond lasers. • The temporal performance of MCP-PMT under femtosecond laser is shown as a function of photon number. [ABSTRACT FROM AUTHOR]

North Night Vision Tech. Ltd.(NNVT) supplied 15,000 pieces of 20-inch Microchannel plate photomultiplier tubes (MCP-PMTs) with high detective efficiency and light detection coverage for Jiangmen Underground Neutrino Observatory (JUNO) experiment for neutrino detection. The uniformity of the large-area PMT is a very important parameters, it directly affects the detective efficiency when the light illuminates on the PMT photocathode. The performances including the uniformity of the MCP-PMTs should be tested carefully before transaction and transportation in NNVT. Therefore a facility with high test efficiency and high automation is necessary to be designed and constructed to monitor the uniformity of 20-inch MCP-PMTs. In this paper, we describe and compare three development stages and methods of the uniformity scanning platform and the uniformity result of all MCP-PMTs are presented. [ABSTRACT FROM AUTHOR]

Abstract: This manuscript discusses a new design of large area MCP-PMT for the next generation neutrino experiments. The main motivation of the design is to improve the quantum efficiency (photo detection efficiency) of the PMT. Two sets of small MCP units, the transmission photocathode coated on the front hemisphere and the reflection photocathode coated on the rear hemisphere are assembled in the same glass envelope to form nearly 4π viewing angle to enhance the efficiency of the photoelectron detection. The photoelectrons from the 4π photocathode are collected and amplified by two sets of MCP units. Our goal is eventually to produce 20 in. diameter PMT following such an approach. We will report preliminary results of our ptoelectronic simulation and the results of a 5 in. diameter prototype PMT. Future plans and prospects are discussed at the end. [Copyright &y& Elsevier]

This manuscript reports a study of the after-pulse properties of different types of 20-inch photomultiplier tubes (PMTs), especially for the 20-inch microchannel-plate-PMTs (MCP-PMTs) for JUNO experiment. In the study, the after-pulse rate (APR) is calculated from PMT waveforms obtained by a CAEN DT5751 waveform digitizer. We tested the after-pulse characteristics of both Dynode-PMTs and MCP-PMTs and made a thorough study on the after-pulses of high quantum efficiency (HQE) MCP-PMT for JUNO experiment, including their time distribution, after-pulse rate and the causes of different after-pulse groups through flight time analysis. Based on a fast test method, individual tests on 28 HQE-MCP-PMTs on the after-pulses were conducted at the North Night Vision Tech. Ltd. (NNVT) in Nanjing in December of 2019. This paper reports the average APR under two different definitions for HQE-MCP-PMTs and the proportions of the five different after-pulse groups. [ABSTRACT FROM AUTHOR]

The microchannel plates (MCP) can serve as the electron amplifier of the photomultiplier tubes (PMT). The collection efficiency of the newly developed 8-inch MCP-PMT for the Jinping Neutrino Experiment is maximized thanks to the high-secondary-emission coating. The resulting single electron response (SER) charge distribution deviates from the Gaussian distribution in large charge regions. To understand the nature of the jumbo-charged SER, we designed a voltage-division experiment to quantify the dependence of the MCP gain on the energy of incident electrons. Combining the relationship with the Furman probabilistic model, we reproduced the SER charge spectra by introducing an additional amplification stage on the input electrode of the first MCP. Our results favor a Gamma-Tweedie mixture to describe the SER charge spectra of the MCP-PMTs. [ABSTRACT FROM AUTHOR]

The use of time-of-flight (TOF) technology in positron emission tomography (PET) is expected to enhance the performance of clinical tasks such as lesion detection and disease staging. One critical requirement for TOF-PET is achieving lower Coincidence Time Resolution (CTR). In this manuscript, we developed a kind of multi-anode micro channel plate photomultiplier tube (MCP-PMT) specifically designed for TOF-PET applications. The direct use of Cherenkov radiator as the optical window eliminate the optical interface between the radiator and the detector, and the multi-anode structure enables a great positional resolution. Using the fast analog-to-digital converters (FADCs) technology to record the entire waveforms of the signals, the CTR measured by a pair of MCP-PMTs was analyzed offline, and the best CTR of 40. 9 ± 12. 9 ps Full Width at Half Maximum (FWHM), which is equivalent to a position resolution of 6. 1 ± 1. 9 mm line of response (LOR) was obtained. [ABSTRACT FROM AUTHOR]

Abstract This paper describes the design of the 8-inch and 20-inch photomultiplier tubes based on microchannel plates (MCP-PMT). In the large area MCP-PMT, the small MCPs replace the bulky dynode chain in the traditional large PMTs. Photoelectrons are electrostatically focused on MCPs. The MCP assembly, focusing electrodes as well as the supply voltages are carefully optimized to achieve a wide photosensitive area, high photon detection efficiency and good timing resolution. Highlights • The electron-optics design of the large-area spherical MCP-PMT and the elliptical MCP-PMT is described. • The effect of the photoelectron angle of incidence on the first MCP on the collection efficiency are discussed. • The Earths magnetic field effects on the 20-inch MCP-PMT are studied. • The method employed to design the large-area MCP-PMT can be also used in optimizing other large format photon detectors. [ABSTRACT FROM AUTHOR]

With the proposal of the road map of Time-of-Flight positron emission tomography (TOF-PET) with a Coincidence Time Resolution (CTR) of 10 ps by Paul Lecoq et al. in 2020, the technology based on TOF puts forward higher requirements on the performance of its core optical devices. In this manuscript, we developed a kind of Multi-Anode micro channel plate photomultiplier tube (MCP-PMT) based on Cherenkov radiator window. By using the Cherenkov radiator as the optical window of Multi-Anode MCP-PMT directly, the optical interface between the scintillator and the PMT window in conventional TOF-PET is eliminated, reducing light loss and further improve the time resolution of TOF-PET. The anode of this MCP-PMT can be split into a finely spaced array of collecting electrodes to achieve good positional sensitivity. In this paper, the single photon detection capability and time resolution of this kind of MCP-PMT are evaluated. The transit time spread (TTS) at single photon mode can reach 42.9 ps, and the TTS at multi photon mode is less than 10 ps. The CTR based on this kind of MCP-PMT is 156.7 ± 10.6 ps FWHM, which is equivalent to a position resolution of 23.5 ± 1.6 mm along a line of response (LOR). The performance uniformity of this kind MCP-PMT has also been calibrated. • A new Multi-anode MCP-PMT with Cherenkov Radiator Window. • The time resolution of this kind of MCP-PMT is less than 40 ps sigma. • The coincidence time resolution based on this kind of MCP-PMT is 156.7 ps FWHM. • This kind of multi-anode MCP-PMT shows great uniformity in gain and time resolution. [ABSTRACT FROM AUTHOR]

A novel large-area (20-inch) photomultiplier tube based on microchannel plate (MCP-PMTs) is proposed for the Jiangmen Underground Neutrino Observatory (JUNO) experiment. Its photoelectron collection efficiency C e is limited by the MCP open area fraction ( A open ). This efficiency is studied as a function of the angular ( θ ), energy ( E ) distributions of electrons in the input charge cloud and the potential difference ( U ) between the PMT photocathode and the MCP input surface, considering secondary electron emission from the MCP input electrode. In CST Studio Suite, Finite Integral Technique and Monte Carlo method are combined to investigate the dependence of C e on θ , E and U . Results predict that C e can exceed A open , and are applied to optimize the structure and operational parameters of the 20-inch MCP-PMT prototype. C e of the optimized MCP-PMT is expected to reach 81.2%. Finally, the reduction of the penetration depth of the MCP input electrode layer and the deposition of a high secondary electron yield material on the MCP are proposed to further optimize C e . [ABSTRACT FROM AUTHOR]

Small-sized Micro-Channel-Plate Photomultiplier Tube (MCP-PMT) has attracted extensive attention in the fields of high-energy physics, medical imaging and biological detection due to its high timing resolution. We report the R&D of a novel single anode MCP-PMT with ultrafast rise time (RT) and transit time spread (TTS), which is called fast-timing PMT (FPMT). In this paper, we mainly optimize the time performance of FPMT by simulation and experiments in three parts, including the gap distance between the MCP and anode, anode structure and high voltage distribution on the electrodes. The results show that by optimizing the anode structure of FPMT, the RT of single-anode FPMT is significantly improved from 1.4 ns to 215 ps and the TTS from 71 ps to 35.8 ps. By optimizing the high voltage distribution of the FPMT, the RT and the TTS are further improved, and the trend of the change in relative time performance with the change in high voltage distribution is analyzed. Finally, a single-anode FPMT with a RT of 153 ps and a TTS of 27.2 ps is realized. • A simulation model of FPMT is build to optimize the time performance. • The RT of single anode MCP-PMT is greatly improved from nanoseconds to hundreds of picoseconds. • Anode design. • The RT and TTS of single-anode FPMTs are further improved by optimizing the voltage divider ratio. • The time resolution of single-anode MCP-PMT can reach 4.2 ps. [ABSTRACT FROM AUTHOR]

Since microchannel plate (MCP) photomultiplier tubes are used mainly to detect weak signals, their utility is greatly affected by their noise. This is true, for example, for the 20-inch MCP photomultiplier tubes used in high-energy physics research. We have built an MCP luminescence test system by coincidence testing method, and have analyzed the sources of such MCP luminescence by contrast test. We find that this MCP luminescence is due to electron multiplication in the photomultiplier tube. In order to analyze the proportion of MCP luminescence noise in an MCP photomultiplier tube, a noise model of the tube is established, including various sources of noise such as thermal electron emission from photocathode, MCP luminescence, MCP noise electron, glass luminescence, and ion feedback. Then we set up a test and evaluation system of MCP luminescence, measuring count-rate variations of 20-inch MCP photomultiplier tubes under incident light with different numbers of photoelectrons per pulse and different pulse rates. Through a series of calculations, the ratio of the noise from the MCP luminescence to the total noise of the 20-inch MCP photomultiplier tubes was determined. The results show that the luminescence noise of the MCP accounts for about 7 to 22% of the noise of the whole tube. Our analytic method can be extended to analyze the main noise sources of other MCP-type photomultiplier tubes, a direction worth pursuing to reduce noise and further improve the overall performance of MCP photomultiplier tubes. [ABSTRACT FROM AUTHOR]

The 20-inch MCP-PMT employs microchannel plates (MCP) as the electron multiplier unlike the traditional photomultiplier tubes (PMTs) with the dynode structure. According to the performance requirements for 20-inch PMTs to be used in the Hyper-Kamiokande (Hyper-K) project, North Night Vision Technology Co., Ltd. (NNVT) developed a novel 20-inch MCP-PMT based on the modification of the 20-inch MCP-PMT used for the Jiangmen Underground Neutrino Observatory by optimizing the design of the focusing electrode structure, the fabrication of the photocathode, and the other processes. The performance of the new NNVT 20-inch MCP-PMTs was evaluated and compared with respect to time resolution and noise. It was found that the transit time spread of the novel type is lower than 4 ns and the dark count rate is lower than 15 kHz. Compared to the previous model, the novel 20-inch MCP-PMT presents enhanced performance for time resolution and noise that is promising for its use in high-energy physics applications such as neutrino detection. [ABSTRACT FROM AUTHOR]

Researchers of IHEP have conceived a new concept of MCP-PMT several years ago. Small MCP units replace the bulky Dynode chain in the large PMTs. In addition, transmission and reflection photocathodes are in the same glass bulb to enhance the efficiency of photoelectron conversion. After three years of R&D, a number of 8 inch prototypes were produced in 2013. The 20 inch prototypes followed in 2014 and their performances were improved a lot in 2015. This type of PMT has large sensitive area, high quantum efficiency (QE), and large peak-to-valley (P/V) ratio for good single photoelectron detection. Taking in account the performance and cost of PMT and the radioactivity of PMT glass, JUNO ordered 15000 20-inch MCP-PMT from North Night Vision of Technology CO.(NNVT) in Dec.2015. The MCP-PMT collaboration group finished to build the mass production line in Nanjing, and finished the batch test system in the same place in 2016. From 2017 to 2019, all the 20-inch PMTs are produced and tested individually in NNVT. This paper will focus on the mass production and batch test result of 6000 pieces of MCP-PMT prototypes for JUNO. [ABSTRACT FROM AUTHOR]

A new concept of large area photomultiplier based on MCPs was conceived for JUNO by the scientists in IHEP, and with the collaborative work of the MCP–PMT collaboration in China, 8 in. and 20 in. prototypes were produced. Test results show that this type of MCP–PMT can have good SPE performance as the traditional dynode type PMTs. [ABSTRACT FROM AUTHOR]