Search arXiv⌕ Search

arXiv · physics/0511212

Advanced Photodetectors for Hyperspectroscopy and Other Applications

Abstract

Hyperspectroscopy is a new method of surface image taking, providing simultaneously high position and spectral resolutions which allow one to make some conclusions about chemical compositions of the surfaces. We are now studying applications of the hyperspctroscopic technique to be used for medicine. This may allow one to develop early diagnostics of some illnesses, as for example, skin cancer. For image taking advanced MCPs are currently used, sensitive in the spectral interval of 450-850 nm. One of the aims of this work is to extend the hyperspectrocpic method to the UV region of spectra: 185-280 nm. For this we have developed and successfully tested innovative 1D and 2D UV sealed photosensitive gaseous detectors with resistive electrodes. These detectors are superior MCPs due to the very low rate of noise pulses and thus due to the high signal to noise ratio. Other important features of these detectors are that they have excellent position resolutions - 30 micron in digital form, are vibration stable and are spark protected. The first results from the application of these detectors for spectroscopy, hyperspectroscopy and the flame detection are presented.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

I. Rodionov, J-M. Bidault, I. Crotty, P. Fonte, F. Galy, V. Peskov, O. Zanette. 2005-11-25. Advanced Photodetectors for Hyperspectroscopy and Other Applications. https://doi.org/10.1109/nssmic.2005.1596972

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Small but Tubby: A Magnetic Loop Antenna Made from 100 mm Copper Tubing

This paper presents the electrical model, key equations, and practical construction of a small transmitting magnetic loop antenna built from unusually large 100 mm diameter copper tubing. The large conductor surface area and wide-area transitions to the vacuum capacitors were designed to minimize resistive losses. The frequency range from 1.8 MHz to 31 MHz is unusually wide. Frequency, impedance matching, and azimuth are all adjusted automatically by servo motors. Indoor losses originate predominantly from near-field coupling to the environment rather than from the antenna itself. Temperature-rise measurements confirm that the bulk of the dissipated power is absorbed by the environment, not by the antenna components. The conducted H-field measurements demonstrate good agreement between the measured H-field and the theoretical free-space H-field calculated from the antenna geometry and an estimated loop current. The loop current was estimated from the measured antenna bandwidth and the applied transmit power. The antenna was developed for indoor operation where outdoor installation is not possible.

physics.ins-det↗

Triaxial $μ$-PIC for resolving Multi-Hit Ambiguity

The micro pixel chamber ($μ$-PIC), a type of micro-pattern gaseous detectors (MPGD), features pixel electrodes structured similarly to a sliced proportional counter. Conventionally, $μ$-PIC electrodes are connected to orthogonal strip electrodes to reduce the number of readout circuits; however, this configuration introduces multi-hit ambiguity when tracing winding tracks or during high-rate operations. A well-known solution to this problem is the adoption of an additional readout axis. To this end, we designed a new electrode structure using Garfield++ simulations and fabricated a triaxial $μ$-PIC based on through-glass-via (TGV) technology. This triaxial $μ$-PIC achieved a high gas gain of $1.1\times 10^4$ and the energy resolution of 22\% (FWHM) at 5.9~keV, Furthermore, the false-hit probability was less than 0.78\% at a 95\% confidence level for two clusters separated by a distance of over 3 mm, consistent with Garfield++ predictions. With this triaxial $μ$-PIC, single avalanche signals are collected from three independent readout strip electrodes (the anode and two cathodes). The charge ratio among these electrodes remains nearly constant at anode:U-cathode:V-cathode=3:2:1. In addition, we successfully achieved an enhanced gain of $3.2\times 10^4$ without increasing the discharge risk by employing an alternative operation mode.

physics.ins-det↗

Experimental Characterization of Bulk Micromegas for Development of Active Target Time Projection Chamber for Nuclear Astrophysics Studies

A Micromegas-based active target Time Projection Chamber, namely Saha Active Target TPC (SAT-TPC), is under development at Saha Institute of Nuclear Physics for its application in nuclear astrophysics experiment to measure the branching ratio of the direct and sequential decay of the Hoyle state of $^{12}$C. A bulk Micromegas was characterized to optimize its operating parameters and its performance for $α$-particle tracking was investigated using gas mixtures Ar + CO$_{2}$ (90:10) and Ar + i-C$_4$H$_{10}$ (95:5) at atmospheric pressure using 5.9~keV X-ray and 5.48~MeV $α$-particles from radioactive sources. A hydrodynamic transport model was used to simulate the charge-deposit profile of the $α$-particle track on the Micromegas readout and compared to the experimental data to complement the experimental measurement as well as validate the numerical model. A good agreement was observed that confirmed the suitability of the choice of the bulk Micromegas in the development of the SAT-TPC prototype and the hydrodynamic modelling of the detector dynamics

physics.ins-det↗