Experimental investigation of silicon photomultipliers as compact light readout systems for gamma-ray spectroscopy applications in fusion plasmas

A matrix of Silicon Photo Multipliers has been developed for light readout from a large area 1 in. x 1 in. LaBr3 crystal. The system has been characterized in the laboratory and its performance compared to that of a conventional photo multiplier tube. A pulse duration of 100 ns was achieved, which opens up to spectroscopy applications at high counting rates. The energy resolution measured using radioactive sources extrapolates to 3%-4% in the energy range E gamma = 3-5 MeV, enabling gamma-ray spectroscopy measurements at good energy resolution. The results reported here are of relevance in view of the development of compact gamma-ray detectors with spectroscopy capabilities, such as an enhanced gamma-ray camera for high power fusion plasmas, where the use of photomultiplier is impeded by space limitation and sensitivity to magnetic fields

A wide dynamics neutron monitor with BF3 and logarithmic amplifier based front-end electronics

In this paper a wide dynamics neutron monitor based on BF3 neutron detector is described. The detector is used in current mode, and a front-end electronics based on a logarithmic amplifier is used in order to have a measurement capability ranging over many decades. The system has been calibrated at Polytechnic of Milan, CESNEF, with an AmBe neutron source, and has been tested in a pulsed field at the PUNITA facility at JRC, Ispra. The detector has achieved a dynamics ranging over 6 decades, proving able to measure single neutron pulses and showing saturation-free response for a reaction rate up to 10^6 s^-1. It has also proved effective in measuring the PUNITA facility pulse integral fluence.JRC.E.8-Nuclear security (Ispra

Test of the ΔE/E Silicon Microdosimeter at the CATANA Facility

ISSN: 1082-365

A neutron detector for pulsed mixed fields: preliminary measurements

It is well-known that neutron detectors generally suffer from dead-time effects and have strong limitations when measuring in pulsed radiation fields. An active neutron monitor based on a BF3 proportional counter and logarithmic electronics was developed to withstand pulsed fields with high intensity, very short duration and high repetition rate. This paper discusses results of preliminary measurements carried out at the Italian National Hadrontherapy Center (CNAO) in Pavia and at the San Raffaele Hospital in Milan. In the first case neutrons were produced by 7 MeV protons accelerated by a LINAC and impinging on a copper Faraday cup. In the second case an electron radiotherapy LINAC produced energy-tunable bremsstrahlung x-rays beams up to 18 MV with an associated neutron component. The neutron monitor was capable to withstand neutron reaction rates up to 2·106 s-1 without showing saturation effects. A promising technique is also shown to reject very intense, pulsed gamma fields, due to the innovative operating principle of the detector

A Micrometric Thickness Silicon Diode Proposed as a Microdosimeter

N15-

Disseminated cutaneous leishmaniasis after visceral disease in a patient with AIDS

Leishmaniasis is emerging as a common and serious opportunistic disease for patients with HIV infection. Almost all cases of HIV-Leishmania coinfection have been described in Mediterranean countries and they occur with various clinical presentations, ranging from typical visceral forms to asymptomatic or atypical cases, including cutaneous and mucocutaneous leishmaniasis. Pentavalent antimony compounds have been the mainstays of antileishmanial therapy for half a century and new lipid formulations of amphotericin B seem reliable, but the most effective treatment remains unknown. We describe a patient who was HIV infected and an intravenous drug user, with an unusual disseminated cutaneous leishmaniasis, after an initial visceral disease and after a 13-month maintenance treatment with liposomal amphotericin. The severe concurrent immunosuppression probably played an essential role in leading to this atypical cutaneous form, characterized by diffuse, nonulcerated, nonscabby maculopapular lesions

New silicon microdosimeter production based on improved monolithic silicon telescope technology

In the framework of developing instrumentation aimed at measuring radiation quality, a new production of improved silicon microdosimeters based on the Monolithic Silicon Telescope (MST) technology has been recently finalized. Reduced dead layer, high fluence rate capability and better chord length distribution have been obtained thorough modified process and design. Electrical and functional tests have been successfully completed and are presented