[en] This study is part of a project aimed at developing a new monitoring system to improve measurements of lung retention for ²³⁹Pu. To cover the thoracic volume, the proposed system uses silicon detectors operating at room temperature. This report gives the first conclusions of this feasibility study. The results were obtained using a detection module composed of silicon strip detectors. Analogue electronics were specially designed to optimise signal-to-noise ratio and to investigate background by using anticoincidence between the silicon detectors. Overall counting efficiency determination was carried out by scanning the surface of a Livermore phantom. Combining these measurements, the detection limits are discussed for the complete modular system with emphasis on the competition between efficiency and background to demonstrate the innovative feature of such a system as an alternative to germanium detectors systems. The proposed new monitoring system may enable the detection limit for ²³⁹Pu to be lowered by a factor of 2. (author)

[en] We implemented a low noise current preamplifier for the readout of resistive bolometers. We tested the apparatus on thermometer resistances ranging from 10 to 500 MΩ. The use of current preamplifier overcomes constraints introduced by the readout time constant due to the thermometer resistance and the input capacitance. Using cold JFETs, this preamplifier board is shown to have very low noise: the Johnson noise of the source resistor (1 fA/Hz^1/2) dominated in our noise measurements. We also implemented a lock-in chain using this preamplifier. Due to fast risetime, compensation of the phase shift may be unnecessary. If implemented, no tuning is necessary when the sensor impedance changes. Transients are very short, and thus low-passing or sampling of the signal is simplified. In case of spurious noise, the modulation frequency can be chosen in a much wider frequency range, without requiring a new calibration of the apparatus

[en] A beam detector system, CATS (Chambre A Trajectoires de Saclay), was designed to provide event-by-event particle tracking in experiments with radioactive beams at GANIL. It consists of two low pressure multiwire proportional chambers with one plane of anode wires placed between two cathode planes (active area: 70x70 mm²), respectively segmented into 28 vertical or horizontal strips (2.54 mm wide). The anode wires deliver a time signal allowing a time of flight measurement with an accuracy between 440 ps and 1.2 ns, depending on the energy loss of incident particles in the detector. The cathode strips are individually read out and the position of incoming particles is reconstructed using a charge centroid finding algorithm. A spatial resolution of 400 μm (700 μm) was achieved during in beam experiment, with a counting rate of 1.5x10⁵ (10⁶) particles per second. (author)

[en] Although much progress was made by using high purity germanium detectors for direct measurement of ²³⁹Pu in man, the improvement of lung spectroscopy sensitivity remains a challenge. Previous work showed that passivated implanted planar silicon detectors could provide an alternative by combining high-energy resolution at room temperature and planar geometry with large detection arrays. This paper reports on the status of this research based on the characterisation of 3x3 cm² and 6x3 cm² strip silicon detectors. Furthermore, the possibility to apply such detectors towards other monitoring problems for accidental situations such as the direct measurement of small contaminated surfaces was investigated. (author)

[en] SAPhIR is the acronym for S_aclay A_quitaine P_hotovoltaic cells for I_somer R_esearch. It consists of solar cells, used for fission-fragment detection. It is a collaboration between 3 laboratories: CEA Saclay, CENBG Bordeaux and CEA Bruyeres le Chatel. The coupling of a highly efficient fission-fragment detector like SAPhIR with EUROBALL will provide new insights in the study of very deformed nuclear matter and in the spectroscopy of neutron-rich nuclei