Search

The effect of total ionizing dose on a commercial optomechanical microswitch has been studied in this paper. One microswitch was irradiated using a Co60γ-ray radiation source at a dose rate of 330 rad/h to total dose up to 22.5 krad (Si). Little effect was observed in this device which is consistent with the technological design that does not contain insulators. [ABSTRACT FROM AUTHOR]

A new capillary plate (CP) has been developed for a hole-type micropattern gas detector. The plate consists of a bundle of fine soda-glass capillaries with a diameter of 100 μm and a length of 1 mm. The electrodes on the surfaces of both ends of CP were coated with Inconel metal. The plate is similar to a conventional CP, except that the material used is not lead glass, but soda glass. The main advantages of the soda-glass CP compared to the lead-glass CF are a low surface resistivity and low background properties. The soda-glass CF gas detector was operated with a gas mixture of Ar(90%) + CH4(8%) + TMA(2%) using 5.9 keV X-rays. Using the scintillation light emitted from the soda-glass CP, we successfully obtained the energy spectrum and accumulated image for the 5.9 keV X-rays. In this paper, we report on the characteristics of the new soda-glass CF and the background properties of both the soda-glass and lead-glass CPs. We also describe the outlook on the future development of an optical gas photomultiplier with the soda-glass cP. [ABSTRACT FROM AUTHOR]

We present a compact, fully integrated, low power baseline restorer for radiation detector readout ASICs. The proposed circuit has been designed, simulated, and layed out using a 0.35 μm CMOS technology. It features an area occupancy of 90 × 100 μm² and a power consumption of 90 μW for 3.3 V power supplies, which makes it suitable for highly packed multi-channel detector readouts. In the paper the principle of operation of the circuit as well as the results of the simulations are discussed. [ABSTRACT FROM AUTHOR]

The necessary shapings for optimum processing of signals from radiation detectors can be conveniently obtained by using an analog prefilter followed by an analog-to-digital converter (ADC) and a digital filter. In this paper we analytically calculate the dependence of resolution and efficiency of energy measurements on the characteristics of the analog prefilter architecture. Consequent design rules of the analog stage are derived and different solutions are proposed and discussed. [ABSTRACT FROM AUTHOR]

The Fermilab Recycler ring will employ an electron cooler to store and cool 8.9 GeV antiprotons. The cooler will be based on a Pelletron electrostatic accelerator working in an energy-recovery regime. Several techniques for determining the characteristics of the beam dynamics are being investigated. Beam profiles have been measured as a function of the beam line optics at the energy of 3.5 MeV in the current range of 10-4 -1 A, with a pulse duration of 2 μs. The profiles were measured using optical transition radiation produced at the interface of a 250-μm aluminum foil and also from YAG crystal luminescence. In addition, beam profiles measured using multiwire detectors were investigated. These three diagnostics will be used together to determine the profile dynamics of the beam. In this paper we report the results so far obtained using these techniques. [ABSTRACT FROM AUTHOR]

Experimental data are presented showing that, for a light heavy ion such as Carbon, large collection-efficiency losses appear in Silicon Surface Barrier detectors for large enough ion fluences. This effect, apparently related to the onset of radiation damage of the detector, shows an S-shape behavior with the fluence above threshold. [ABSTRACT FROM AUTHOR]

A new domain of application of monolithic active pixel sensors, with respect to particle tracking, has been triggered by the innovative idea of a nondestructive beam monitoring system in the extraction lines of a hadron-theraphy center. The beam monitoring exploits secondary electrons emitted from a submicrometer thick AI foil, intersecting the beam. Electrons are accelerated in an electrostatic field. The detection of low-energy electrons, up to 30 keV, is required. The sensitivity to these energies is obtained by thinning the detector, originally fabricated in a standard VLSI technology, down to the thickness of the radiation sensitive layer. A thin entrance window, in the order of 100 nm, is provided. Monolithic active pixel sensors for low-energy electron imaging can be prospectively used in several domains: in bioscience for cell process study using radiotracers, e.g., ³H(18 keVβ- ) or fluorescence imaging exploiting the Hybrid Photodiodes principle, in safety or environmental studies for neutron imaging with converters directly deposited or in micro-beam facilities for position resolving in studies of living cell irradiations. The low-energy electron imaging capabilities for installation inside an HPD test facility and the results obtained with ³H marked source are shown. The detector used is the 1 × 106 pixel MIMOSA V chip. The back-thinning up to the epitaxial layer was applied, resulting in a high resolution, back-side illuminated imager. [ABSTRACT FROM AUTHOR]

Passive gamma-ray spectrometers composed of attenuation filters and integrating detection materials provide important advantages for measurements in high-radiation environments and for long-term monitoring. Each of these applications has requirements that constrain the design of the instrument, such as incident energy range of interest, sensor size and weight, readout method, and cost The multitude of parameters in passive spectrometer design (e.g., attenuation filter material and thickness, integrating sensor type, number of pixels, reconstructed energy bin structure) results in a large design space to examine. The development of generalized design optimization tools to interrogate this space and to identify promising spectrometer designs is discussed, particularly the methods used to rapidly calculate system transfers functions and the use of genetic algorithms for design optimization. Preliminary measurements to validate the design tools are described, and example results from early design optimization efforts are provided. [ABSTRACT FROM AUTHOR]