Prospects for new inorganic scintillators

Abstract

[ [ ) . frJ r;y;)Prepared for the U.S. Department of Energy under Contract Number DE-AC03-76SF00098..... DISCLAIMERThis document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. ABSTRACTAlthough scintillation has been discovered in many inorganic crystals during the past 40 years, there is continued interest in finding compounds with improved scintillation properties. However, the testing of candidate compounds has thus far been limited to those available as crystals of suitable quality and size. We describe a method using synchrotron x-radiation for measuring the fluorescence properties of powders, which makes accessible a much larger number of compounds. We present results for 85 compounds tested by this method. Scintillation from several compounds was discovered, notably CeF3 and PbC03.

Design of a pulsed X-ray system for fluorescent lifetime measurements with a timing accuracy of 109 ps

“…Interesting fluorescent emissions were detected from several compounds by this method, including CeF3, PbC03, PbS04, Yh203, CeCl3, BaCl2. and Cui [1,2]. At the same time, a light-excited x-ray tube was developed for producing very brief (,;, 100 ps) pulses of x-rays ( Figure 1) [3].…”

Design and characterization of a pulsed x-ray source for fluorescent lifetime measurements

“…New scintillators could also reduce the detector cost. In previous efforts to find new scintillators, an electron synchrotron was used in single-bunch mode to measure the x-ray excited fluorescence of over 400 compounds [1,2], but use of a synchrotron is costly and time-consuming. In an effort to reduce the cost and increase the ease of making these measurements, my colleagues and I have developed a bench-top pulsed x-ray source.…”

Further Measurements Of The Scintillation Properties Of Lead Carbonate

“…Measurements were made on powdered samples of lead carbonate having different purity and chemical form, namely 99.999% basic lead carbonate 2(PbC03)·Pb(OH)2, 99.999% lead carbonate PbC03, and 99.9995% lead carbonate PbC03. Note that the first sample (99.999% basic lead carbonate) was the compound used in reference [9].…”

“…An accurate measurement of the fluorescence decay time and an estimate of the total light output of a scintillator can be made by exciting a powdered sample of the scintillator with a nanosecond wide burst of x-rays from ·a synchrotron light source, then observing the emitted light with a photomultiplier tube [9]. The decay time spectrum of each sample is obtained using the delayed coincidence method [5] where a signal synchronized with the x-ray arrival time was generated with a plastic scintillator and a photomultiplier tube [10].…”

“…Consequently, the first scintillation lifetime measurements were made with a powdered sample of basic lead carbonate 2(PbC03)·Pb(OH)2 excited with 22.7 keV xrays [9] and subsequent measurements were made with an optical quality cerussite crystal [1]. As a result, there -5- LBL-29740 has been some speculation that the fluorescence Table 2: Decay time fit and light output of powdered sample properties are not intrinsic, but are the result of an of lead carbonate.…”