Si-APD array detector for a single X-ray photon detection with high timing resolution, energy resolution, and high rate capability (#1160)
T. Masuda1, S. Okubo1, H. Hara1, T. Hiraki1, S. Kitao2, Y. Miyamoto1, K. Okai1, R. Ozaki1, N. Sasao1, M. Seto2, S. Uetake1, A. Yamaguchi3, Y. Yoda4, A. Yoshimi1, K. Yoshimura1
1 Okayama University, Research Institute for Interdisciplinary Science, Kitaku, Okayama, Japan
We have developed a six-channel array silicon avalanche photodiode (Si-APD) detector that measures both energy and timing of a single X-ray photon with high rate capability. This system is designed for experiments that use high intensity synchrotron radiation X-ray beams especially nuclear resonant scattering. This system realizes an overall time resolution of 120 ps (full width at half maximum) or 56 ps (sigma) which is one of the best among array type Si-APD detectors. Not only the overall time resolution, it also realizes quite short tail component: the temporal profile rapidly downs to 10-9 level at 1 ns apart from the peak. The high rate capability even with energy measurement is one of features of this system. It can acqure energy information of each single X-ray photon in rate of more than 106 counts per second for one channel. The rate torelance is realized by originally desiged fast amplitude-to-time convertors and commercial time-to-digital convertors. We demonstrated the performance of the system in SPring-8.
Keywords: X-ray detector, Si-APD, photon counting
New generation photosensors for the Hyper-Kamiokande detector (#4027)
V. Berardi1, 2
1 INFN, Bari, Bari, Italy
On behalf of Hyper-Kamiokande proto collaboration
Hyper-Kamiokande is the next upgrade of the currently operating Super-Kamiokande experiment. The ambitious physics program of Hyper-Kamiokande, that is CP violation, neutrino mass ordering and, ultimately, proton decay searches, can be successfully carried on only by increasing the performances of the photosensors installed on the walls of the Water Cherenkov detector filled with 520000 metric tons of ultrapure Water. Such a detector is predicted to have a fiducial volume which will be approximately 20 times larger than its precursor, and since the capability of a the water Cherenkov detector largely relies on the performance of its photosensors, it is thus necessary to develop a new generation of photosensors.
We will thus present the current status of development of Hyper-K detector photosensors reviewing the effort in improving the performances of the 20 inches photosensors as well as the newly proposed mPMT scheme.
Keywords: neutrino, photodetector, Hyper-Kamiokande
The Status of the R&D of the 20 inch MCP-PMT in Chin (#1742)
S. Qian1, Q. Zhang2, G. Huang2
1 Chinese Academy of Sciences (CAS), The institute of the High Energy Physics, beijing, China
Researchers at IHEP have conceived a new con-cept of MCP-PMT several years ago for JUNO (Jianmen Underground Neutrino Observatory). The small MCP (Microchannel Plate) units replace the bulky Dynode chain in the tranditional large PMTs. In addition transmission photocathode on the front hemisphere and reflection photocathode on the rare hemisphere are fabricated in the same glass bulb to form nearly 4π effective photocathode in order to enhance the efficiency of photoelectron conversion.
A number of experienced researchers and engineers in research institutes and companies related to PMT fabrication in China jointly worked on the large area MCP-PMT project. After three years R&D, a number of 8-inch prototypes were produced and their performance was carefully tested at IHEP in 2013 by using the MCP-PMT evaluation system built at IHEP. The 20 inch prototypes were followed in 2014, and its’ performance were improving a lot in 2015. Compensating the PMT performances with fiducially volume convert all specifications to cost, radioativity, dark noise, TTS, the JUNO ordered 15000 pic 20-inch MCP-PMT from the NNVT in Dec.2015. In 2016, the MCP-PMT collaboration group finished to build the mass production line batch test system in NNVT Company in Nanjing. From 2017 to 2019, all the 20-inch MCP-PMT will be produced and tested one by one in NNVT for JUNO.
In this manuscript, the characteristics of this type if 20-inch MCP-PMT was carefully studied by measuring the I-V curves of the transmission pho-tocathode (Trans. PC), the quantum efficiency (QE) vs. wavelength, and the mapping the QE. Charge spectra of single photoelectrons, timing properties of anode signals and anode linearity were measured. Noise characteristics and after pulse properties were studied at gain ~1.0×107. The behaviors of the aging of the prototype, and the performance in the earth magnetic field will be discussed in this presentation.
Keywords: MCP, PMT
Recent progress on planar microchannel plate photomultiplier development for fast timing and imaging applications (#4194)
1 Argonne National Laboratory, Lemont, Illinois, United States of America
Micro-channel plate (MCP) detectors are sensitive to single photons, provide both picosecond-level time resolution and sub-mm level position resolution, suitable for applications require both precision timing and imaging.
The Argonne MCP-PMT detector group has recently designed and fabricated planar MCP-PMTs with 6 cm x 6 cm active areas. A fused silica window was used to achieve full range response covering ultraviolet-visible-infrared range detections. Initial characterization indicates that the newly developed photomultipiers exhibit a transit-time spread of 57 ps at single photoelectron detection mode and of 27 ps at multi-photoelectron mode (~100 photoelectrons). Rate capability testing performed at the Fermilab test beam facility shows high rate capability up to 75 kHz/cm2, proving it as a possible sensor candidate for future high rate applications.
An improved MCP-PMT design with pixelated readout is currently being studied. With the planned pixelated readout, the new MCP-PMT will provide even better position resolution for imaging applications, enhancing its capability in different experiments requiring both precision timing and imaging such as Belle II and EIC. The progress on pixelated readout MCP-PMT production and characterization will also be presented and discussed in the presentation.
Keywords: Micro-channel plate, photomultiplier, picosecond-level time resolution
Development of Opaque Photocathodes Deposited onto Microchannel Plates (#3859)
C. Ertley1, O. Siegmund1, J. Tedesco1, A. Tremsin1, J. Hull1, N. Darling1, J. Elam2, A. Mane2
1 University of California, Berkeley, Space Sciences Laboratory, Berkeley, California, United States of America
Atomic layer deposition (ALD) techniques are being used to manufacture microchannel plate (MCP) imaging electron multipliers. The MCP substrates are borosilicate microcapillary arrays, which are more robust than traditional lead glass MCPs, allowing them to be produced in large formats (400 cm2) with high open area ratios (up to 85%). The application of resistive and secondary emissive layers using ALD allow custom nanofabrication and optimization of parameters such as gain and resistance. The UV quantum efficiency of bare ALD MCPs exceeds conventional MCPs and application of opaque alkali halide photocathode layers have been investigated. The robust nature of ALD MCPs means they can also withstand the processing temperatures required for high temperature deposition of III-V materials, such as Gallium Nitride (GaN), for UV photocathodes with high QEs in the Near-UV (~200-300nm). Here we discuss the status of the QE of bare ALD MCPs and the results of our opaque photocathode deposition effort onto ALD MCPs. Initial trials of opaque bialkali depositions have been successfully completed showing detection efficiencies commensurate with the highest efficiency semitransparent cathodes. GaN has been grown by molecular beam epitaxy onto sapphire substrates in order to optimized the deposition parameters. These results are being used as a starting point for deposition of GaN directly onto ALD MCPs.
Keywords: Microchannel plate, atomic layer deposition, Photocathode, GaN, bialkali, quantum efficiency
The Tynode: a new vacuum electron multiplier for ultra fast pixelised particle detectors (#3684)
H. van der Graaf1, 2
1 Nikhef, Detector R&D, Amsterdam, NH, Netherlands
By placing, in vacuum, a stack of transmission dynodes (tynodes) on top of a CMOS pixel chip, a generic, digital, single free electron detector could be made with potentially a ps time resolution. Its essential element is the tynode: an ultra thin membrane, which emits, at the impact of an energetic electron on one side, a multiple of electrons at the other side. The electron yields of tynodes have been calculated by means of GEANT-4 Monte Carlo simulations, applying special low-energy extensions. The results are in line with another simulation based on a continuous charge-diffusion model.
By means of MEMS technology, tynodes and test samples have been realised. The secondary electron yield of several tynode prototypes have been measured in three different stations. Our best result so far is a transmission secondary electron yield of 5.5, obtained with an MgO membrane made using Atomic Layer Deposition ALD technology. Several possibilities to improve the yield are presented. A prototype soft photon detector TipsyZero, based on a stack of tynodes placed in a Planacon (Photonis) detector, is now under construction.
Keywords: Transmission dynode, Tynode, Secondary electron yield, photomultiplier