[en] A YAP(YAlO₃:Ce)-scintillating window, coated on its inner surface with an S20-photocathode, seals a cross-focusing hybrid photomultiplier tube (HPMT) equipped with a small p-i-n anode of 2-mm diameter. This new radiation detector separates X-ray lines down to about 2-keV peak energy from the HPMT noise. Its detection efficiency for high gamma energies depends on the YAP-window thickness and amounts to about 18% attenuation at 400-keV energy in the present version. Competitive radiation detectors like silicon photodiodes and silicon drift chambers are discussed and compared to the prototype, with particular attention given to their energy resolution and noise performance, which limits their active area considerably

[en] The electrostatic configuration of the planned Barrel RICH (Ring Imaging CHerenkov) detector for the DELPHI experiment at LEP has been realized as a prototype. The results of extensive tests - up to 200 kV dc - are reported, proving the feasibility of the device and determining/confirming some parameters that cannot be simulated by computer calculations. (orig.)

[en] The ISPA (Imaging Silicon Pixel Array)-tube is a position-sensitive hybrid photon detector. Originally developed for high energy physics purposes, it has also been used for biomedical applications. Two kinds of ISPA-tube prototypes have been tested successfully in the field of gamma ray imaging. The current developments aim at obtaining a detector dedicated to single photon emission imaging. In this paper, we shall present the very first use in a gamma-camera of a new ISPA-tube prototype having an increased active input surface of 40 mm diameter and a de-magnifying electron optics. The expected advantages of an ISPA-tube equipped with an input window made out of YAP-crystal will also be pointed out by presenting results obtained with a Hybrid PhotoMultiplier Tube equipped with such a YAP window

[en] Pure crystalline YAlO₃ can be applied due to its high refractive index as a novel material for optical elements within 240-1000 nm light transmission. If used as front-windows for photon detectors and coated with a photocathode at its vacuum interface, it improves their light collection efficiency. Its high refractive index increases the numerical aperture of lenses and hence their spatial resolving power. It matches favorably with the refractive index of MgF₂, which used as antireflection coating reduces the surface reflectance close to zero. Doped with Ce³⁺-ions, YAlO₃(Ce) can be readily used as scintillating front windows of vacuum-sealed photon detectors for ionizing radiation

[en] The Imaging Silicon Pixel Array (ISPA)-tube is a position-sensitive hybrid photon detector. Originally developed for high-energy physics purposes, it has also been used for biomedical applications. Two kinds of ISPA-tube prototypes have been tested successfully in the field of gamma ray imaging. The current developments aim at obtaining a detector dedicated to single-photon emission imaging. In this paper, we present the first use in a gamma camera of a new ISPA-tube prototype having an increased active input surface of 40 mm diameter and a de-magnifying electron optics. The quartz input window of the tube is optically coupled to a 3.5 cm² YAlO₃:Ce detector array with 0.6 mm² single elements

[en] We have developed a fully automatic measurement set-up, capable of measuring light yields arising from scintillating crystals in a linear range of about four orders of magnitude. The photodetector is a hybrid photomultiplier tube specially developed to optimize linear range and photon detection. Crystal and photodetector are temperature controlled by a closed water circuit, as this is essential when measuring low light yield scintillating crystals with a marked temperature dependence of their light yield. Gamma sources can be placed either on top or on the side of the crystal. In this latter case, the source can be automatically moved by a computer-controlled step motor to provide a uniformity profile of the light yield along the crystal. Tagged and not-tagged operation modes are possible. The whole set-up is computer-controlled in an effort to provide fast and reliable measurements, to characterize many crystals per day. This is important for the quality control of the lead tungstate crystals that will be applied in the electromagnetic calorimeter of the CMS-detector at the LHC at CERN. (author)

[en] We report on the first operation of a hybrid photon detector prototype with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The prototype has been characterized using a low-intensity light-emitting diode operated in pulsed mode. Its performance in terms of single-photoelectron detection efficiency and imaging properties is presented. A model of photoelectron detection is proposed, and is shown to be in good agreement with the experimental data. It includes an estimate of the charge signal generated in the silicon detector, and the combined effects of the comparator threshold spread of the pixel readout chip, charge sharing at the pixel boundaries and back-scattering of the photoelectrons at the silicon detector surface

[en] A new form of flash tube has been investigated as a particle detector, with special interest in its performance at liquid nitrogen temperature. The results indicate that the tubes count efficiently and with sufficiently good time resolution to be able to assist in resolving independent events in bubble-chamber neutrino pictures. (Auth.)

[en] LIBO is a proton accelerator that operates at 3 GHz, the same frequency as the one adopted in the about 7500 electron linacs used for radiotherapy all over the world. Such a high frequency was chosen to obtain a large gradient (on average more than 10 MV/m), and thus a short linac (about 15 m) to boost the energy of the protons, extracted at about 60 MeV from a cyclotron, up to the 200 MeV needed for the treatment of deep-seated tumours. This paper describes the design study of the full 3 GHz Side Coupled Linac (modular structure, nine modules) and the construction and tests of the LIBO prototype (first module), which was built to accelerate protons from 62 to 74 MeV with an RF peak power of 4.4 MW. The items discussed are the beam dynamics parameters of the module (longitudinal and transverse acceptances), the constructional elements and procedures, the accuracies of the various mechanical elements, the cooling system, the RF tuning, the RF measurement and the RF power tests. These tests showed that, after a short conditioning time, the gradient in each of the four tanks of the module could reach 28.5 MV/m, much larger than the nominal project value (15.8 MV/m). The last section of the paper describes the successful acceleration tests performed at the Laboratori Nazionali del Sud of INFN in Catania with a solid-state 3 GHz modulator lent by IBA

No abstract available