Angular sensitivity of modeled scientific silicon charge-coupled devices to initial electron direction

作者：Plimley Brian^*; Coffer Amy; Zhang Yigong; Vetter Kai

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2016, 827: 18-23.

DOI：10.1016/j.nima.2016.04.092

• Charge-coupled device
• CCD
• Electron track
• Compton imaging

Previously, scientific silicon charge-coupled devices (CCDs) with 10.5-mu m pixel pitch and a thick (650 mu m), fully depleted bulk have been used to measure gamma-ray-induced fast electrons and demonstrate electron track Compton imaging. A model of the response of this CCD was also developed and benchmarked to experiment using Monte Carlo electron tracks.
We now examine the trade-off in pixel pitch and electronic noise. We extend our CCD response model to different pixel pitch and readout noise per pixel, including pixel pitch of 2.5 mu m, 5 m,10.5 mu m, 20 mu m, and 40 mu m, and readout noise from 0 eV/pixel to 2 keV/pixel for 10.5 mu m pixel pitch. The CCD images generated by this model using simulated electron tracks are processed by our trajectory reconstruction algorithm. The performance of the reconstruction algorithm defines the expected angular sensitivity as a function of electron energy, CCD pixel pitch, and readout noise per pixel.
Results show that our existing pixel pitch of 10.5 mu m is near optimal for our approach, because smaller pixels add little new information but are subject to greater statistical noise.
In addition, we measured the readout noise per pixel for two different device temperatures in order to estimate the effect of temperature on the reconstruction algorithm performance, although the readout is not optimized for higher temperatures. The noise in our device at 240 K increases the FVVHM of angular measurement error by no more than a factor of 2, from 26 to 49 FVVHM for electrons between 425 keV and 480 keV. Therefore, a CCD could be used for electron-track-based imaging in a Peltier-cooled device.

• 出版日期2016-8-11