CE42 - Capteurs, instrumentation

DIAMond instrumentation for pulsed beam MONItoring – DIAMMONI


DIAMond instrumentation for pulsed beam MONItoring

Pulsed beam monitoring in diamond technology

DIAMMONI aims to develop innovative detectors based on a semiconductor material, diamond, used as a solid ionization chamber with readout electronics (FE) and data acquisition. The main objective is the monitoring of pulsed beams of protons and alpha particles, produced by the ARRONAX cyclotron, in the energy range up to 70 MeV. The cyclotron can indeed operate in continuous pulsed mode (packets lasting 4 ns at a frequency of 30.45 MHz) or in discontinuous mode. The beam is then made up of trains of packets with a duration, and an inter-train, adjustable by the operator.

The beam diagnostics that can be operated by DIAMMONI are as follows:
• count each individual particle at low current, when the number of particles detected on a read channel is 0 or 1 (average intensity of the beam < 100 pA on diamond), measure the temporal distribution of the particles within the bunches to study the the impact of the injection parameters, evaluate the jitter of the packets with respect to the RF buckets (signals from the sensors and the generator),
• measure the peak current and the flux when the particle counting rate is high, between 100 pA and 1 µA in average intensity measured on diamond. This requires that all charges generated by a number of protons N per bunch with N<2x10^5 be collected in less than 30 ns,
• measure the “start” and the “stop” of a packet-train of a few µs, in 30 ns (one packet), and the fluence corresponding to this packet.
• measure cross-sectional features (x and y directions) from beams smaller than the monitor. Here, the position and partial dimensions of the beam can be assessed by sampling the signal at different intensities.

The performances obtained under beams at ARRONAX of electronic developments in discrete components, for the integration of charges in the train with time marking at the start and end of the train validate i) not only the developments proposed but also ii) the use of diamond, as an active volume for instrumentation bundles as a diagnostic device. This first step in DIAMMONI, in relation to the initial objectives of the project, is therefore completed.

The simulation of charge collection in the diamond material as a function of the beam intensity is an ambitious and original work. The results obtained confirm the experimental measurements for low beam intensities where the mechanisms involved are simpler and expected (publications in the literature, laboratory experiments with sources or in beams by members of the consortium). On the other hand, the work of interpreting and modeling the collection of charges by the diamond at high beam intensity (causes, nature and effects of the internal field linked to the local charge density, associated kinematics, recombination phenomenon, etc.) is a challenge that we have set ourselves which will have a major impact in the physics of detectors (not only for solid ionization chambers because there is also a similarity with gaseous ionization chambers). The first results are promising. The next tests will be decisive for the validation of the models. This work will give rise to a publication due at the end of 2023. This is the milestone that we have set ourselves as part of R. Molle's thesis


S. Curtoni, M.-L. Gallin-Martel, L. Abbassi, A. Bes, G. Bosson, J. Collot, T. Crozes, D. Dauvergne, W. De Nolf, P. Everaere, L. Gallin-Martel, A. Ghimouz, F. Haddadd, J.-Y. Hostachy, C. Koumeird, A. Lacoste, S. Marcatili, V. Métivier, J. Morse, J.-F. Motte, J.-F. Muraz, F. Poirier, F. E. Rarbi, O. Rossetto, M. Salomé, N. Servagent, E. Testa, M. Yamouni,
“Performance of CVD diamond detectors for single ion beam-tagging applications in hadrontherapy monitoring”,
Nuclear Inst. and Methods in Physics Research, A, Volume 1015, 2021, 165757, arxiv.org/abs/2105.05053

International conference

Very High Energy Electron Radiotherapy Workshop (VHEE2020), october 2020 CERN, ML Gallin-Martel (conf invité)
NDNC 2020-2021 Japon November 2021 ML Gallin-Martel (oral)
Hassel Diamond Workshop ML Gallin-Martel March 2022 (conf invited)
HIAT 2022 F. Poirier juin 2022 (conf invited)

Conference France

Journées instrumentation détecteur à l’IN2P3 june 2021 IJClab JF Muraz (oral)
Journées R&T IN2P3 IJClab october 2021 ML Gallin-Martel (oral)
Journée Instrumentation faisceaux IN2P3 april2022 R. Molle (oral + poster))
Journée réseau semi-conducteur IN2P3 june 2022 R. Molle (oral)
GDR MI2B journée annuelle june 2022 C. Koumeir (oral)

The development of new generations of ion accelerators, for physics (nuclear - high energy) or for medical applications ("flash" radiotherapy), involves precise monitoring of the beam with fast counting in a highly radiative environment. The intrinsic qualities of diamond (rapidity, low leakage current, excellent signal-to-noise ratio, radiation resistance) make it an excellent candidate to meet such requirements. DIAMMONI is an innovative diamond detector for the online control of pulsed beams. It aims to achieve a spatial resolution of the order of a millimetre (diamond strip metallization), a fast particle counting (design of a current preamplifier) in each nano-pulse of each micro-bunch (time resolution ~ 100 ps) as well as a continuous monitoring of the beam intensity (design of a QDC) on all the dynamics (fraction of pA up to µA)

Project coordination

Marie-Laure Gallin-Martel (Laboratoire de Physique Subatomique et de Cosmologie)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.


LPSC Laboratoire de Physique Subatomique et de Cosmologie
ARRONAX Accélérateur pour la Recherche en Radiochimie et Oncologie à Nantes Atlantique

Help of the ANR 285,772 euros
Beginning and duration of the scientific project: September 2020 - 48 Months

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