A large area diamond-based beam tagging hodoscope for ion therapy monitoring

Abstract

Abstract-. The MoniDiam project is part of the French national collaboration CLaRyS (Contrôle en Ligne del'hAdronthérapie par RaYonnements Secondaires) for on-line monitoring of hadron therapy. It relies on the imaging of nuclear reaction products that is related to the ion range. The goal here is to provide large area beam detectors with a high detection efficiency for carbon or proton beams giving time and position measurement at 100 MHz count rates (beam tagging hodoscope). High radiation hardness and intrinsic electronic properties make diamonds reliable and very fast detectors with a good signal to noise ratio. Commercial Chemical Vapor Deposited (CVD) polycrystalline, heteroepitaxial and monocrystalline diamonds were studied. Their applicability as a particle detector was investigated using α and β radioactive sources, 95 MeV/u carbon ion beams at GANIL and 8.5 keV X-ray photon bunches from ESRF. This facility offers the unique capability of providing a focused (~1 µm) beam in bunches of 100 ps duration, with an almost uniform energy deposition in the irradiated detector volume, therefore mimicking the interaction of single ions. A signal rise time resolution ranging from 20 to 90 ps rms and an energy resolution of 7 to 9% were measured using diamonds with aluminum disk shaped surface metallization. This enabled us to conclude that polycrystalline CVD diamond detectors are good candidates for our beam tagging hodoscope development. Recently, double-side stripped metallized diamonds were tested using the XBIC (X Rays Beam Induced Current) set-up of the ID21 beamline at ESRF which permits us to evaluate the capability of diamond to be used as position sensitive detector. The final detector will consist in a mosaic arrangement of double-side stripped diamond sensors read out by a dedicated fast-integrated electronics of several hundreds of channels. therapy. Ions deposit a large fraction of the dose at the end of their path, in the Bragg peak. Compared to conventional X-ray radiotherapy, hadron therapy allows a more efficient dose delivery in the tumor, with a reduction of the dose deposited in the nearby healthy organs. The conformation of the deposited dose to the tumor volume is provided by distributing Bragg peaks in this volume, either spot by spot, or by means of passive scattering and energy degradation. However, since multiple sources of uncertainty on the ion range may cause deviations from the planned dose distribution [1], online control of the ion range is desired in order to reduce safety margins and optimize the ballistic advantage of ion therapy.During an irradiation with ion beams, nuclear reactions occur for part of the projectiles along their path in the patient body, and photons in the range 1-10 MeV are emitted almost isotropically within much less than a picosecond after the reactions. It has been shown experimentally that the longitudinal distribution of such prompt-gamma production is highly correlated to the primary ion range

Characterization of Diamond and Silicon Carbide Detectors With Fission Fragments

“…For the LPSC diamond detectors: sCVD, pCVD, and DOI, labelled respectively A, C, and F in Table 1, an aluminum disk shaped-metallization was locally performed using DMW (Distributed Microwave Plasmas), a technology developed at LPSC [21] and already described in [22]. For the pCVD detectors D and E, the metallization was performed at NANOFAB at Institut Néel using a liftoff process as described in [10].…”

“…For the pCVD detectors D and E, the metallization was performed at NANOFAB at Institut Néel using a liftoff process as described in [10]. The sensor contact for the disk-shaped metallization consists of a 50 nm (LPSC [22]) or a 100 nm (NANOFAB [10]) thick aluminum layer deposited on both sides. A recent study [10] has proven the "blocking", Schottky-like, nature of such aluminum electrodes.…”

“…Detectors A, C, D, E and F (respectively B) were tested intensively at LPSC (respectively IFJ-PAN) or in-beam prior to present experiment at ILL, as reported in the following two paragraphs and in [10,22].…”

On the Role of Single Particle Irradiation and Fast Timing for Efficient Online-Control in Particle Therapy

“…Thin ultra-fast silicon detectors (UFSD) have been explored for such purpose [43]. Using another technology, we have shown that a temporal resolution close to 100 ps rms is expected by means of diamond detectors, on condition that large areas are available with detector-grade crystals [24,44]. Relatively large polycrystalline diamonds are available and provide such a time resolution for highly ionizing particles such as carbon ions.…”

X‐Ray Thermoluminescence Dosimetry Characterization of Commercially Available CVD Diamond

“…The 3D diamond sensor permits to reach greater performance in the high‐luminosity areas of the LHC experiments, along with the typical high radiation hardness and extreme resistivity values found in bulk diamond . Commercial CVD diamonds are also studied for their applicability as a sensitive detector in hadron therapy with very promising results as prompt‐gamma and beam tagging hodoscope in ion monitoring …”