Author: De Angelis, G.
Paper Title Page
TUPG51 Micro Pattern Ionization Chamber with Adaptive Amplifiers as Dose Delivery Monitor for Therapeutic Proton LINAC 464
  • E. Cisbani, A. Carloni, S. Colilli, G. De Angelis, S. Frullani, F. Ghio, F. Giuliani, M. Gricia, M. Lucentini, C. Notaro, F. Santavenere, A. Spurio, G. Vacca
    ISS, Rome, Italy
  • A. Ampollini, P. Nenzi, L. Picardi, C. Ronsivalle, M. Vadrucci
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • E. Basile
    Azienda Ospedaliera Papardo, Messina, Italy
  • D.M. Castelluccio
    ENEA-Bologna, Bologna, Italy
  • C. Placido
    University of Rome "La Sapienza", Rome, Italy
  Funding: Regione Lazio: TOP-IMPLART project
A dedicated dose delivery monitor is under development for the TOP-IMPLART proton accelerator, the first LINAC for cancer therapy. It is expected to measure the intensity profile to precisely monitor the fully active 3+1D (x/y/z and intensity) dose delivery of each short pulses (few micro-s, 0.1-10 micro-A pulse current at ~100 Hz) of the therapeutic proton beam (up to 230 MeV). The monitor system consists of planar gas chambers operating in ionization regime with cathode plane made ofμpattern pads alternately connected by orthogonal strips*. The dedicated readout electronics features trans-impedance amplifier that dynamically adapts its integrating feedback capacitance to the incoming amount of charge, then opportunistically changing its gain. The measured absolute sensitivity is about 100 fC (better than 0.03 relative sensitivity), the dynamic range up to 10000 (2 gain settings) with time response at the level of few ns, and virtually no dead time. Small scale chamber prototype (0.875 mm pitch pads) and readout electronics have been tested and characterized under both electron (5 MeV) and proton (up to 27 MeV) beams.
* The pad-like design has been adopted to maximize the field uniformity, to reduce the chamber thickness and to obtain both x/y coordinates on a single chamber.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG51  
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