Swift Highly Charged Ion Channelling

We review recent experimental and theoretical progress made in the scope of swift highly charged ion channelling in crystals. The usefulness of such studies is their ability to yield impact parameter information on charge transfer processes, and also on some time related problems. We discuss the cooling and heating phenomena at MeV/u energies, results obtained with decelerated H-like ion beams at GSI and with ions having an excess of electrons at GANIL, the superdensity effect along atomic strings and Resonant Coherent Excitation.Comment: to be published in Journal of Physics

New methods of real-time control imaging for ion therapy

to be published in the proceedings of the NIRS-ETOILE joint symposium on carbon ion therapy, Lyon, 16-17 mars 2009We present the ongoing studies aiming at providing a real-time control of the dose distribution during ion therapy. These studies are undertaken in the frame of the National and Rhône-Alpes Regional Research Programs for Hadontherapy. We aim at implementing combined modalities for real-time quality control of the deposited dose for future therapy centers. Several modalities are under development within this research program. Improvements on Positron Emission Tomography (PET) can be obtained by means of Time of Flight, using fast scintillators or resistive plate chambers, with dedicated readout and electronics. The in-bream prompt gamma imaging looks very promising in view of recent preliminary results, provided Time of Flight is used to discriminate gamma from neutrons and scattered particles. A collimated detection setup or a Compton camera is envisaged. Prompt emission of light charged particles like protons is also discussed

Front-end multi-channel PMT-associated readout chip for hodoscope application

International audienceThe system development requires a dedicated multi-channel readout ASIC (Application Specific Integrated Circuit) to be associated with the MaPMTs. Each channel should have very low input impedance to avoid electrical crosstalk between adjacent channels and to minimize effects of detector and wiring capacitances (Cd + Cw). Crosstalk between channels may degrade position resolution, while these capacitances may degrade both frequency and noise performances. Each channel should also provide two separated outputs corresponding respectively to high-speed signal-event detection and low-noise signal-charge quantification at low counting rate. This paper presents a readout chip for this purpose. It has been designed in a 0.35µm SiGe BiCMOS process (AMS). This process allows the use of RF and large-transconductance bipolar components, which is useful for the design of wide-band, low-impedance and low-noise circuits with improved performances

Statistical effects of dose deposition in track-structure modelling of radiobiology efficiency

Ion-induced cell killing has been reported to depend on the irradiation dose but also on the projectile parameters. In this paper we focus on two approaches developed and extensively used to predict cell survival in response to ion irradiation: the Local Effect Model and the Katz Model. These models are based on a track-structure description summarized in the concept of radial dose. This latter is sensitive to ion characteristics parameters and gives to both models the ability to predict some important radiobiological features for ion irradiations. Radial dose is however an average quantity, which does not include stochastic effects. These radiation-intrinsic effects are investigated by means of a Monte-Carlo simulation of dose deposition. We show that both models are not fully consistent with the nanometric and microscopic dose deposition statistics.Comment: 32 pages ; 8 figure

Refrigeration System for the ATLAS Experiment

The proposed ATLAS detector for the 27 km circumference LHC collider is of unprecedented size and complexity. The magnet configuration is based on an inner superconducting solenoid and large superconducting air-core toroids (barrel and two end-caps) each made of eight coils symmetrically arranged outside the calorimetry. The total cold mass approaches 600 tons and the stored energy is 1.7 GJ. The cryogenic infrastructure will include a 6 kW @ 4.5 K refrigerator, a precooling unit and distribution systems and permits flexible operation during cool-down, normal running and quench recovery. A dedicated LN2 refrigeration system is proposed for the three liquid argon calorimeters (84 m3 of LAr). Magnets and calorimeters will be individually tested prior to their definitive installation in a large scale cryogenic test area on the surface. The experiment is scheduled to be operational in 2005