4 research outputs found
Sub-10ps Monolithic and Low-power Photodetector Readout
Recent advances in photon detectors have resulted in high-density imaging
arrays that offer many performance and cost advantages. In particular, the
excellent transit time spread of certain devices show promise to provide
tangible benefits in applications such as Positron Emission Tomography (PET).
Meanwhile, high-density, high-performance readout techniques have not kept on
pace for exploiting these developments. Photodetector readout for next
generation high event rate particle identification and time-resolved PET
requires a highly-integrated, low-power, and cost-effective readout technique.
We propose fast waveform sampling as a method that meets these criteria and
demonstrate that sub-10ps resolution can be obtained for an existing device.Comment: 12 pages, 20 figures, submitted to NIM
TARGET: A multi-channel digitizer chip for very-high-energy gamma-ray telescopes
The next-generation very-high-energy (VHE) gamma-ray observatory, the
Cherenkov Telescope Array, will feature dozens of imaging atmospheric Cherenkov
telescopes (IACTs), each with thousands of pixels of photo-sensors. To be
affordable and reliable, reading out such a mega-channel array requires event
recording technology that is highly integrated and modular, with a low cost per
channel. We present the design and performance of a chip targeted to this
application: the TeV Array Readout with GSa/s sampling and Event Trigger
(TARGET). This application-specific integrated circuit (ASIC) has 16 parallel
input channels, a 4096-sample buffer for each channel, adjustable input
termination, self-trigger functionality, and tight window-selected readout. We
report the performance of TARGET in terms of sampling frequency, power
consumption, dynamic range, current-mode gain, analog bandwidth, and cross
talk. The large number of channels per chip allows a low cost per channel (\10
to \20 including front-end and back-end electronics but not including
photosensors) to be achieved with a TARGET-based IACT readout system. In
addition to basic performance parameters of the TARGET chip itself, we present
a camera module prototype as well as a second-generation chip (TARGET~2), both
of which have been produced.Comment: 16 pages, 15 figures, version 3 (matches version published in
Astroparticle Physics
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High Resolution Photon Timing with MCP-PMTs: A Comparison of a Commercial Constant Fraction Discriminator (CFD) with the ASIC-based Waveform Digitizers TARGET and WaveCatcher
There is a considerable interest to develop new time-of-flight detectors using, for example, micro-channel-plate photodetectors (MCP-PMTs). The question we pose in this paper is if new waveform digitizer ASICs, such as the WaveCatcher and TARGET, operating with a sampling rate of 2-3 GSa/s can compete with 1GHz BW CFD/TDC/ADC electronics. We have performed a series of measurements with these waveform digitizers coupled to MCP-PMTs operating at low gain and with a signal equivalent to {approx}40 photoelectrons. The tests were done with a laser diode on detectors operating under the same condition used previously in SLAC and Fermilab beam tests. Our test results indicate that one can achieve similar resolution with both methods. Although the commercial CFD-based electronics does exist and performs very well, it is difficult to implement on a very large scale, and therefore the custom electronics is needed. In addition, the analog delay line requirement makes it very difficult to incorporate CFD discriminators in ASIC designs