Scintillation

About: Scintillation is a research topic. Over the lifetime, 14022 publications have been published within this topic receiving 187694 citations.

CCD readout of GEM-based neutron detectors

Abstract: We report on the optical readout of the gas electron multiplier (GEM) operated with a gaseous mixture suitable for the detection of thermal neutrons: 3 He–CF4. A CCD system operating in the 400–1000 nm band was used to collect the light. Spectroscopic data on the visible and NIR scintillation of He–CF4 are presented. Images of the tracks of the proton and triton recorded with a triple GEM detector are also shown. r 2002 Elsevier Science B.V. All rights reserved. PACS: 29.40.Gx

Sensitivity, Resolution, and Linearity of the Scintillation Camera

Abstract: Radioisotope cameras are relatively new instruments for imaging the distribution of ?-ray or positron-emitting isotopes in vivo. They produce pictures similar to those made by medical radioisotope scanners, showing the uptake of tracer compounds in tumors and organs. Cameras can produce pictures in much less time than scanners because of their higher sensitivity and their ability to view all parts of the subject continuously. In the scintillation camera described here, an array of 19 multiplier phototubes view a single, large, thin, sodium iodide crystal. From the relative amount of light seen by each phototube when a scintillation is produced, the position is determined in two dimensions and it is displayed as a point flash of light on an oscilloscope. Pictures are obtained by taking a time exposure of the oscilloscope screen. Pinhole or parallel multichannel collimation is used with ?-ray emitters, and coincidence techniques are used with positron emitters.

An investigation of the digital discrimination of neutrons and γ rays with organic scintillation detectors using an artificial neural network

Abstract: The discrimination of neutron and γ-ray events in an organic scintillator has been investigated by using a method based on an artificial neural network (ANN) Voltage pulses arising from an EJ-301 organic liquid scintillation detector in a mixed radiation field have been recorded with a fast digital sampling oscilloscope Piled-up events have been disentangled using a pile-up management unit based on a fitting method Each individual pulse has subsequently been sent to a discrimination unit which discriminates neutron and γ-ray events with a method based on an artificial neural network This discrimination technique has been verified by the corresponding mixed-field data assessed by time of flight (TOF) It is shown that the characterization of the neutrons and photons achieved by the discrimination method based on the ANN is consistent with that afforded by TOF This approach enables events that are often as a result of scattering or pile-up to be identified and returned to the data set and affords digital discrimination of mixed radiation fields in a broad range of environments on the basis of training obtained with a single TOF dataset

Performance measurements of a depth-encoding PET detector module based on position-sensitive avalanche photodiode read-out.

Abstract: We are developing a high-resolution, high-efficiency positron emission tomography (PET) detector module with depth of interaction (DOI) capability based on a lutetium oxyorthosilicate (LSO) scintillator array coupled at both ends to position-sensitive avalanche photodiodes (PSAPDs). In this paper we present the DOI resolution, energy resolution and timing resolution results for complete detector modules. The detector module consists of a 7 x 7 matrix of LSO scintillator crystals (1 x 1 x 20 mm3 in dimension) coupled to 8 x 8 mm2 PSAPDs at both ends. Flood histograms were acquired and used to generate crystal look-up tables. The DOI resolution was measured for individual crystals within the array by using the ratio of the signal amplitudes from the two PSAPDs on an event-by-event basis. A measure of the total scintillation light produced was obtained by summing the signal amplitudes from the two PSAPDs. This summed signal was used to measure the energy resolution. The DOI resolution was measured to be 3-4 mm FWHM irrespective of the position of the crystal within the array, or the interaction location along the length of the crystal. The total light signal and energy resolution was almost independent of the depth of interaction. The measured energy resolution averaged 14% FWHM. The coincidence timing resolution measured using a pair of identical detector modules was 4.5 ns FWHM. These results are consistent with the design goals and the performance required of a compact, high-resolution and high-efficiency PET detector module for small animal and breast imaging applications.

Luminescence and scintillation properties of the small band gap compound LaI3:Ce3+

Abstract: LaI 3 :Ce 3+ has the smallest band gap in the LaX 3 :Ce 3+ (X=F, Cl, Br, I) series and hence a potentially higher scintillation yield. The luminescence properties of LaI 3 :Ce were investigated by means of optical, X-ray, and γ-ray excitation. Unexpectedly, the compound is a poor scintillator at room temperature but presents good scintillation properties for temperatures below 100 K where Ce 3+ emission is observed peaking at 452 and 502 nm with a yield of ∼16 000 photons/MeV. The drastic thermal quenching of luminescence is explained by the proximity of the Ce 3+ lowest 5d excited state to the host conduction band. Autoionization of Ce 3+ therefore prevents any scintillation effect at room temperature. The positions of Ce 3+ levels relative to the host bands were estimated.