The aim of the DRAGO project, supported by Italian INFN, is the development of a high-resolution, compact γ-ray imager, based on the Anger Camera principle. In this configuration, the light generated by a unique scintillator is read by an array of 77 Silicon Drift Detectors. In order to locate the position of interaction of the photon inside the scintillator, it is necessary to make an amplification and filtering of the detector signals followed by a processing of the acquired data. The electronics readout and processing system can be divided in two separate parts: the analog front end and the DAQ board. The analog front end is composed of 80 readout channels divided in 10 CMOS chips, produced in the 0.35 μm AMS technology, each one processing 8 channels. Each analog channel of the circuit includes a low-noise preamplifier, a sixth-order semigaussian shaping amplifier with four selectable peaking times from 1.8 μs up to 6 μs, a peak stretcher and a baseline holder. The energy resolution measured using a single channel of the chip with a Silicon Drift Detector Droplet (SD3) is of 128 eV FWHM at 6 keV with the detector cooled at −20 °C. The 8 analog channels of the chip are multiplexed to a single analog output and fed to the acquisition system. For each γ event, this system performs the A/D conversion of all the signals of the array and sends them to a host PC, where the position reconstruction algorithm is executed. The DAQ board contains 10 ADCs, each one dedicated to a single ASIC of the analog section and having a resolution of 13 bit (ENOB). The burst conversion rate of the 10 ADCs together is 50 Ms/s resulting in a dead time of about 2 μs/event. The converted data are stored in a FIFO memory, for buffering, and then are transferred to the host PC via a USB 2.0 interface, which allows an event rate of more than 40k events/s for the whole Anger Camera, compatible with the application.

The electronics readout and the DAQ system of the DRAGO Anger Camera

Gola, Alberto Giacomo;
2008

Abstract

The aim of the DRAGO project, supported by Italian INFN, is the development of a high-resolution, compact γ-ray imager, based on the Anger Camera principle. In this configuration, the light generated by a unique scintillator is read by an array of 77 Silicon Drift Detectors. In order to locate the position of interaction of the photon inside the scintillator, it is necessary to make an amplification and filtering of the detector signals followed by a processing of the acquired data. The electronics readout and processing system can be divided in two separate parts: the analog front end and the DAQ board. The analog front end is composed of 80 readout channels divided in 10 CMOS chips, produced in the 0.35 μm AMS technology, each one processing 8 channels. Each analog channel of the circuit includes a low-noise preamplifier, a sixth-order semigaussian shaping amplifier with four selectable peaking times from 1.8 μs up to 6 μs, a peak stretcher and a baseline holder. The energy resolution measured using a single channel of the chip with a Silicon Drift Detector Droplet (SD3) is of 128 eV FWHM at 6 keV with the detector cooled at −20 °C. The 8 analog channels of the chip are multiplexed to a single analog output and fed to the acquisition system. For each γ event, this system performs the A/D conversion of all the signals of the array and sends them to a host PC, where the position reconstruction algorithm is executed. The DAQ board contains 10 ADCs, each one dedicated to a single ASIC of the analog section and having a resolution of 13 bit (ENOB). The burst conversion rate of the 10 ADCs together is 50 Ms/s resulting in a dead time of about 2 μs/event. The converted data are stored in a FIFO memory, for buffering, and then are transferred to the host PC via a USB 2.0 interface, which allows an event rate of more than 40k events/s for the whole Anger Camera, compatible with the application.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11582/16209
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