eLine10k: A High Dynamic Range Front-End ASIC for LCLS Detectors

Abstract

Abstract-eLine10k is a fast-frame, 64-channel readout ASIC for SLAC Linac Coherent Light Source (LCLS) detectors. The circuit has been designed to integrate the charge from highcapacitance 2D sensors with rolling shutter and 1D strip sensors. It is suitable for applications requiring large input signal range, on the order of 10 4 photons/pixel/pulse at 8keV (22Me -), and a resolution of half a photon FWHM (500e -r.m.s). 2D sensors with a rolling shutter like the X-ray Active Matrix Pixel Sensor (XAMPS), for which the ASIC has been optimized, present several pixels which are bussed on the same readout line. Large input capacitance to each channel is expected leading to stringent noise optimization requirements. The large required number of pixels per channel, and the fixed LCLS beam period impose limitations on the time available for the readout of each single pixel. Giving the periodic nature of the LCLS beam, the ASIC developed for this application is a time-variant system, providing low-noise charge integration, filtering and correlated doublesampling, and a processing speed up to 500k pixel/s on each channel. To cope with the large input dynamic range, a charge pump scheme has been implemented using a synchronous zerobalance measurement method. It provides on-chip 4-bit coarse digital conversion of the integrated charge. The residual charge is sampled using correlated double sampling into an analog memory, multiplexed and measured with the required resolution using an external ADC. In this paper, the ASIC architecture and performance of the final release are presented.

sLine: A High Voltage Switcher ASIC for LCLS Detectors with Rolling Shutter

“…In applications like XCPS, the col isolated from the collection area by mean potential barriers. In other cases, the switch (XAMPS [1,4]). The "switches" associated w a column are connected to the same readou gates (named transfer gates) of those associate in a row are activated simultaneously.…”

“…Two different column-parallel readout detectors with rolling shutter are under development: one based on the X-ray Active Matrix Pixel Sensor (XAMPS) [1,4] in collaboration with Brookhaven National Laboratory and one based on the X-ray Charge Pump Sensor (XCPS) [2][3]. Targeted for different kinds of experiments, both systems feature sensors with pixels that can gate the charge transfer by means of dedicated control lines common to the pixels in a single row.…”

“…1) is a high voltage switcher Application Specific Integrated Circuit (ASIC) that complements the eLine class [4][5][6] of multichannel time-variant integrating front-end ASICs that SLAC has developed for the readout of high capacitance 2D sensors with rolling shutter, and for 1D strip sensors. The class is composed of two front-end ASICs, one designed for high-dynamic range applications (eLine10k [4][5]) and one designed for ultra-low noise applications (eLine100 [6]). Optimized for the XCPS, each channel of the ASIC can independently operate two control lines replicating low voltage control patterns at high voltages.…”

eLine100: A Front End ASIC for LCLS Detectors in Low Noise Applications

“…Sometimes, like in XCPS, the collecting nodes are isolated from the collection area by means of controllable potential barriers. In other cases, the switch could be a FET (XAMPS [1,6]). The "switches" associated to the pixels in a column are connected to the same readout line, while the gates (named transfer gates) of those associated with the pixels in a row are activated simultaneously.…”

“…1) is the latest addition to the new "eLine" class of multichannel time-variant integrating frontend Application Specific Integrated Circuits (ASIC) that SLAC has developed for the Linac Coherent Light Source (LCLS). The class is composed of two front-end ASICs, one designed for high-dynamic range applications (eLine10k [1]) and one designed for ultra-low noise applications (eLine100). The class also includes a switcher ASIC (sLine [2]) used to control the operation of column-parallel readout 2D sensors with rolling shutter such as the X-ray Charge Pump Sensor (XCPS), based on a concept by Pavel Rehak from Brookhaven National Laboratory [3] and under development at SLAC.…”