利用费米实验室质子束研究 PbF$_2$ 晶体中的切伦科夫光子产生

Fast and Efficient Detection of 511 keV Photons using Cherenkov Light in PbF$_2$ Crystal coupled to a MCP-PMT and SAMPIC Digitization Module

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…

Lead fluoride Cherenkov detector read out by avalanche photodiodes for measuring the intensities of pulsed antiproton beams

A Cherenkov detector based on an array of five lead fluoride ($β$-PbF$_2$) crystals of size 30 mm$\times$30 mm$\times$160 mm read out by reverse-type avalanche photodiodes (APD's) of active area 10 mm$\times$10 mm was used to measure the flux of secondary particles emerging from the annihilation of pulsed beams of antiprotons at the Antiproton Decelerator of CERN. We compared the relative photon yields of radiators made of $β$-PbF$_2$, fused silica, UV-transparent acrylic, lead glass, and a lead-free, high-refractive-index glass. Some {\it p-i-n} photodiodes were also used for the readout, but…

Studies of an array of PbF2 Cherenkov crystals with large-area SiPM readout

The electromagnetic calorimeter for the new muon (g-2) experiment at Fermilab will consist of arrays of PbF2 Cherenkov crystals read out by large-area silicon photo-multiplier (SiPM) sensors. We report here on measurements and simulations using 2.0 -- 4.5 GeV electrons with a 28-element prototype array. All data were obtained using fast waveform digitizers to accurately capture signal pulse shapes versus energy, impact position, angle, and crystal wrapping. The SiPMs were gain matched using a laser-based calibration system, which also provided a stabilization procedure that allowed gain correc…

Design and performance of SiPM-based readout of PbF2 crystals for high-rate, precision timing applications

We have developed a custom amplifier board coupled to a large-format 16-channel Hamamatsu silicon photomultiplier device for use as the light sensor for the electromagnetic calorimeters in the Muon g-2 experiment at Fermilab. The calorimeter absorber is an array of lead-fluoride crystals, which produces short-duration Cherenkov light. The detector sits in the high magnetic field of the muon storage ring. The SiPMs selected, and their accompanying custom electronics, must preserve the short pulse shape, have high quantum efficiency, be non-magnetic, exhibit gain stability under varying rate con…

Characterization and Performance of PADME's Cherenkov-Based Small-Angle Calorimeter

The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in Italy, will search for invisible decays of the hypothetical dark photon via the process $e^+e^-\rightarrow γA'$, where the $A'$ escapes detection. The dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We report here on measurement and simulation studies of the performance of the Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting 2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of PbF$_2$ cryst…

探索用于MIP定时探测器的闪烁体和切伦科夫辐射体

Exploring Scintillators and Cherenkov Radiators for MIP Timing Detectors

本文通过蒙特卡洛模拟和CERN SPS实验，测试了快速发光材料作为MIP定时探测器的性能，发现切伦科夫材料时间分辨率达24-36 ps，闪烁体低于15 ps（最佳12.1 ps），并探讨了BaF2掺杂钇的改进效果。