Data Acquisition Board for a Beam-Tagging Hodoscope Used in Hadrontherapy Monitoring

International audienceThere have been suggested methods to implement real-time ion-range monitoring for quality assurance in hadrontherapy. Prompt gamma (PG) detection is a promising technique and several prototypes using various modalities are under developments worldwide. Some systems use time-of-flight (TOF) measurements to discriminate PG from the neutron background (e.g. TOF PG cameras), while others employ Prompt Gamma Timing approach for indirect measurement of ion range. All require precise measurement of arrival time of incident ions detected by a beam-tagging hodoscope. One type of such hodoscopes for this purpose has been developed by CLaRyS collaboration network (consisting of several IN2P3 laboratories). It consists of an array of scintillating fibers in vertical and horizontal directions. The optical fibers are coupled to multi-anode photomultipliers.We report here the development of a data acquisition (DAQ) board to be associated with a scintillating-fiber-based hodoscope. The board incorporates two 32-channel readout ASICs, a FPGA (StratixII GX EP2SGX30C/D) and an optical transceiver (enhanced small form-factor pluggable transceiver). Each readout ASIC also integrates a time-to-digital converter (TDC) and a multiplexed analog output for monitoring of scintillating fibers ageing. The FPGA performs data processing, transmission and slow control. The transceiver performs electrical-and-optical-signal conversion and bidirectional transmission at 3 Gbit/s rate. Via an optical fiber, the board can be connected to a μTCA-based data acquisition system. The board also include a clock jitter cleaner (LMK04828) to generate several clock signals from an external reference clock. The board supports two types of triggers: a self-trigger for stand-alone tests and an external trigger for coupling with imaging systems like prompt gamma cameras. In order to optimize data throughput, the transceiver uses only basic 8-/10-bit protocol and fully exploits specific control symbols to distinguish different types of frames (control, monitoring, and data).The board was designed to meet the system requirements: 1-mm spatial resolution, 1-ns timing resolution, and 100-MHz counting rate capability. To ensure time-measuring precision and transmission reliability, phase determination and frequency synchronization techniques were implemented. The board was fabricated and its operation was verified by test benches. Beam tests (with hodoscope and acquisition system) have been scheduled and are being prepared

Prompt-gamma detection towards absorbed energy monitoring during hadrontherapy

International audienceHadrontherapy is an emerging technique which exploits the fact that a large quantity of the energy of the incident particles is deposited at the end of their flight path. This allows a conformation of the applied dose to the tumor volume and a simultaneous sparing of surrounding healthy tissue. A real-time control of the ion range during the treatment is possible via the detection of prompt secondary radiation (gamma rays or charged particles). Besides a monitoring of the ion range, the knowledge of the total energy absorbed inside the patient is also of importance for an improvement of the treatment quality. It has been shown that the ambient dose in a treatment room is correlated to the monitoring units, i.e. the number of protons of the beam delivery system. The present study consists in applying time-of-flight (TOF) information to identify prompt gamma-rays generated by interactions inside the patient which provides a direct information on the energy imparted. Results from test measurements will be given, which show that events generated in the nozzle and the target phantom can be discriminated. Furthermore, a standalone detection system is being developed which will be read out by a standard PC. The status of the developments for the corresponding electronics will be presented

DEVELOPMENT OF COMPTON CAMERA PROTOTYPE FOR HADRONTHERAPY MONITORING AND MEDICAL IMAGING

International audienc

On the role of single particle irradiation and fast timing for efficient online-control in particle therapy

International audienceWithin the frame of the CLaRyS collaboration, we discuss the assets of using a reduced-intensity in 19 vivo treatment control phase during one or a few beam spots at the beginning of a particle therapy 20 session. By doing so we can improve considerably the conditions for secondary radiation detection 21 and particle radiography. This also makes Time-of-Flight (ToF) resolutions of 100 ps rms feasible for 22 both the transmitted particles and secondary radiations, by means of a single-projectile counting 23 mode using a beam-tagging monitor with time and position registration. This opens up new 24 perspectives for prompt-gamma timing and Compton imaging for range verification. ToF-based 25 proton computed tomography (CT) and ToF-assisted secondary proton vertex imaging in carbon 26 therapy are also discussed, although for the latter, no evidence of any benefit at small observation 27 angles is anticipated. The reduction of the beam intensity during one or a few spots on the various 28 accelerators for particle therapy should not significantly reduce the patient workflo

Characterization of a beam-tagging hodoscope for hadrontherapy monitoring

International audienceA beam tagging hodoscope prototype made of squared 1 mm2 fibers arranged in two perpendicular planes and coupled to multi-anode photomultipliers has been studied using 65 MeV proton as well as 95 MeV/u 12C beams at various intensities. This hodoscope successfully provided 2D images of proton beams with a detection efficiency larger than 98% with logical OR condition between the two fiber planes. The detection efficiency with a coincidence between the two planes is close to 75% for beam intensities up to ~1 MHz. Moreover, the timing resolution is around 1.8 ns FWHM. Overall, the performances show that such a technology is viable for beam monitoring during hadrontherapy

Etiquetage spatio-temporel et monitorage de faisceaux pulsés : applications en hadronthérapieet thérapies « flash »

National audienc

Where Brain, Body and World Collide

The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| < 0.8) in the transverse momentum range 1 < pt < 8 Gev/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy sqrt{s} = 7 TeV using an integrated luminosity of 2.2 nb^{-1}. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs

J/ψJ/\psi production and nuclear effects in p-Pb collisions at SNN\sqrt{S_{NN}} = 5.02 TeV

Inclusive J/$\psi$ production has been studied with the ALICE detector in p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV at the CERN LHC, in the rapidity domains 2.03 < y$_{cms}$ < 3.53 and −4.46 < y$_{cms}$ < −2.96, down to zero transverse momentum. The J/$\psi$ measurement is performed in the Muon Spectrometer through the $\mu^+\mu^−$ decay mode. In this Letter, the J/$\psi$ production cross section and the nuclear modification factor R$_{pPb}$ for the rapidities under study are presented. While at forward rapidity a suppression of the J/$\psi$ yield with respect to binary-scaled pp collisions is observed, in the backward region no suppression is present. The ratio of the forward and backward yields is also shown differentially in rapidity and transverse momentum. Theoretical predictions based on nuclear shadowing, as well as on models including, in addition, a contribution from partonic energy loss, are in fair agreement with the experimental results.Inclusive J/$\psi$ production has been studied with the ALICE detector in p-Pb collisions at the nucleon-nucleon center of mass energy $\sqrt{s_{\rm NN}}$ = 5.02 TeV at the CERN LHC. The measurement is performed in the center of mass rapidity domains $2.03<y_{\rm cms}<3.53$ and $-4.46<y_{\rm cms}<-2.96$, down to zero transverse momentum, studying the $\mu^+\mu^-$ decay mode. In this paper, the J/$\psi$ production cross section and the nuclear modification factor $R_{\rm pPb}$ for the rapidities under study are presented. While at forward rapidity, corresponding to the proton direction, a suppression of the J/$\psi$ yield with respect to binary-scaled pp collisions is observed, in the backward region no suppression is present. The ratio of the forward and backward yields is also measured differentially in rapidity and transverse momentum. Theoretical predictions based on nuclear shadowing, as well as on models including, in addition, a contribution from partonic energy loss, are in fair agreement with the experimental results