A Time-Of-Flight Gamma Camera Data Acquisition System for Hadrontherapy Monitoring

Abstract : A collimated gamma camera consisting of a multi-parallel slit collimator and an absorber has been proposed to be coupled with a beam hodoscope for ion-range verification during hadrontherapy by means of Prompt Gamma (PG) detection. The beam hodoscope associated to this gamma camera provides information on the incident ion position and arrival time to improve the PG image reconstruction and time-of-fight measurement. The data acquisition (DAQ) system of this detection system has been designed to meet the specifications: 1 µs trigger delay, timing resolution < 1 ns, 100 kHz trigger rate and a few 108 bits/s final data rate. It consists of 8 frond-end (FE) readout boards of two types: 2 boards for the hodoscope and 6 boards for the absorber. These FE boards have the same basic structure, consisting of a FPGA, an optical transceiver and a multi-channel analog readout module. The main difference between the two types of FE boards is that the former incorporates two 32-channel readout ASICs, and the latter employs 8-channel DRS4 (Domino Ring Sampling) mezzanines (3 for each board). In addition the system also includes a data-communication module, mainly composed of a data transmission control board called AMC40 which has a 1-Gbit/s Ethernet link for PC connection and 36 available 3 Gbit/s optical links to FE readout boards. On the other hand, we have developed the firmware of every FE board FPGA to realize several multi-phase clock time-to-digital (TDC) convertors: one for the system synchronization and the others for particle’s arrival time tagging. For the 2 hodoscope FE boards, FPGA firmware implementation includes an adjustable-depth measured-data buffer, an histogram-based fast time-of-flight estimation, coincidence-event searching and data zero-suppression. Our designed DAQ system has recently been tested successfully with a reduced-size collimated camera configuration coupled with the beam hodoscope in the Mediterranean proton therapy Institute in Nice (France).
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https://hal.archives-ouvertes.fr/hal-02309735
Contributor : Béatrice Rayet <>
Submitted on : Wednesday, October 9, 2019 - 3:10:00 PM
Last modification on : Friday, October 11, 2019 - 1:04:07 AM

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  • HAL Id : hal-02309735, version 1

Citation

X. Chen, O. Allegrini, B. Carlus, C. Caplan, L. Caponetto, et al.. A Time-Of-Flight Gamma Camera Data Acquisition System for Hadrontherapy Monitoring. IEEE MIC 2019, Oct 2019, Manchester, United Kingdom. ⟨hal-02309735⟩

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