EMPIX - A High Dynamic Range Diamond Pixel Detector for Ultra-fast Electron Diffraction and Microscopy
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2021-10-16 |
| Journal | 2021 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) |
| Authors | Tianyu Wei, Z. Deng, X. Wang, Rongjin Li |
| Institutions | Tsinghua University |
| Citations | 1 |
Abstract
Section titled āAbstractāThe paper presents the development of a high dynamic range diamond pixel detector for ultra-fast electron diffraction and microscopy. First the detector response has been simulated by allpix <sup xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā xmlns:xlink=āhttp://www.w3.org/1999/xlinkā>2</sup> , including energy deposition and the trajectory distribution. Compared with current silicon or CdTe detectors, diamond detectors show much less scattering for 3 MeV electrons and hence could potentially achieve better imaging resolution. Charge collection and transient signal response have also been simulated under pulsed high-flux electron radiation using our previously developed carrier propagation module. The pulse duration of electron source is on the order of femtoseconds and each pulse contains up to 10 <sup xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā xmlns:xlink=āhttp://www.w3.org/1999/xlinkā>5</sup> electrons. Simulation results for 200 Ī¼m diamond detectors show that as the flux increases, the charge cloud explodes. According to the simulation results, the pixel size and the thickness of the detector were designed to be 150 Ī¼m and 200 Ī¼m respectively. A prototype readout ASIC (EMPIX) was also designed. It integrates 32 Ć 8 pixels and each pixel consists of a dual range charge integrator, a correlated double sampler and a 12-bit Wilkinson type ADC. By adaptive gain adjustment design, the maximum integration charge is up to 12.5 pC, corresponding to 10 <sup xmlns:mml=āhttp://www.w3.org/1998/Math/MathMLā xmlns:xlink=āhttp://www.w3.org/1999/xlinkā>4</sup> injected 3 MeV electrons. The readout circuit design was verified and evaluated in electronic test. The equivalent noise charge is tested to be 563 electrons.