FrontierScience G.P.1 MATRIX an innovative Pixel Ionization Chamber for Online Monitoring of Hadrontherapy Treatments Giuseppe Pittà TERA Foundation for Oncological Hadrontherapy

FrontierScience G.P.2 MATRIX PIXEL IONIZATION CHAMBER for on-line control system 2D information on: DOSE delivered to patient during the irradiation BEAM POSITION treatment planning specifications Collaboration between TERA, the University of Torino, INFN - Torino and the University of Piemonte Orientale “A. Avogadro”

FrontierScience G.P.3 Anode Cathode Front-end boards Mylar window Structure of the detector Anode: 1024 pixelsAnode: 1024 pixels Sensitive area: 21 × 21 cm 2Sensitive area: 21 × 21 cm 2 Pixel dimension: 6.5 × 6.5 mm 2Pixel dimension: 6.5 × 6.5 mm 2

FrontierScience G.P.4 Anode and Cathode Sensitive area: 1024 pixels Guard rind Connection with front-end boards – pads for connectors Very thin ANODE Kapton: 50  m - Copper: 17  m GLUING The anode and the cathode are glued on the fiberglass frames with a non- conducting epoxy araldite

FrontierScience G.P.5 Front-end electronics READ-OUT TTL digital outputTTL digital output Maximum digital count frequency: 5 MHzMaximum digital count frequency: 5 MHz Quantum of charge adjustable in the range fCQuantum of charge adjustable in the range fC Tested minimum read-out time for the full chamber: 1 ms.Tested minimum read-out time for the full chamber: 1 ms channels1024 channels 8 electronic boards8 electronic boards 16 TERA06 chips16 TERA06 chips MATRIX - Fully assembled

FrontierScience G.P.6 First beam tests at the cyclotron of JRC (Ispra, Italy) MATRIX

FrontierScience G.P.7 Conteggi al secondo Very low electronic noise: less than one count per second per channel Beam tests at the cyclotron of JRC First run (end of November 2004) Beam energy: 17 MeV Beam current: 5 nA 2 D map of the beam

FrontierScience G.P.8 25 cm 50 cm 100 cm Simulation (SRIM) Beam tests at the cyclotron of JRC 400  m Al exit window 400  m Al exit window Longitudinal displacements of Longitudinal displacements of 25, 50, 100 cm in air

FrontierScience G.P.9 Beam tests at the Loma Linda University Medical Center First hospital-based proton therapy centre, built in 1993First hospital-based proton therapy centre, built in /sessions a day160/sessions a day

FrontierScience G.P.10 MATRIX at LLUMC MATRIX HV and LV power supplies Room for proton-therapy - horizontal beam

FrontierScience G.P.11 The first measurements 5 cm diameter collimator (about 6 cm at isocenter) 14 x 14 cm square field (about 15 x 15 cm at isocenter)

FrontierScience G.P.12 Calibration No calibration Calibration Data taken with the chamber in three different positions with a constant beam (base position, 90 o rotation, 6.5 mm displacement)Data taken with the chamber in three different positions with a constant beam (base position, 90 o rotation, 6.5 mm displacement) No assumptions on the shape of the beamNo assumptions on the shape of the beam Flatness of < 2% has been obtainedFlatness of < 2% has been obtained

FrontierScience G.P.13 Stability Constant beam intensity Constant beam intensity Counting Vs Monitor Units Counting Vs Monitor Units The linearity is better then 2 per mill The linearity is better then 2 per mill

FrontierScience G.P.14 Bragg Peak Depth in water (mm) Total sum (Counts) E beam = 149 MeV E beam = 149 MeV Absorbers of water equivalent material Absorbers of water equivalent material

FrontierScience G.P.15 Beam shape MATRIX in a rotating gantry Beam shaped for a prostate cancer

FrontierScience G.P.16 Pencil beam MATRIX in the experimental room Pencil beam

FrontierScience G.P.17 Conclusions and Outlook The MATRIX pixel ionization chamber has been successfully constructed and tested The MATRIX pixel ionization chamber has been successfully constructed and tested Several beam tests at JRC and LLUMC on Several beam tests at JRC and LLUMC on –Beam shape –Calibration –Bragg Peak –Spot scanning MATRIX is a very powerful detector that can be used for precision monitoring of dose and beam position during hadrontherapy treatments MATRIX is a very powerful detector that can be used for precision monitoring of dose and beam position during hadrontherapy treatments