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Title: RESEARCH ON GROWING OF CADMIUM SULFIDE CRYSTALS FOR DOSIMETER PURPOSES. Quarterly Report No. 4 for the Period January 17, 1958 to April 17, 1958

Abstract

Studies were made of the growth of cadmium salfide in alumina tubes replacing tbe quartz tubes previously used. The objective was to decrease the contamination of the cadmium sulfide with silica. Spectrographic analyses of the unvolatilized cadmium sulfide charge in the alumina tubes showed a much lower concentration of silicon, and the deposited cadmium sulfide single crystals also contained less silicon, although the deposition plate was polished quartz. Studies of the single crystals produced in this apparatus have not yet been sufficiently evaluated to state conclusively the effect of a lower concentration of silicon. The two crystals having the best properties from the standpoint of gamma-ray detection had a silicon concentration of 10 to 20 ppm which is less than the normal concentration. By the use of a secondary deposition plate durian crystal growth the total recovery of usable crystalline cadmium salfide was increased to 83% of theoretical. Studies of optimum seeding conditions indicated that the presence of a small amount of either zinc or silver improved the seeding characteristics of the cadmiuin sulfide. It was found that cadmium sulfide crystals of high resistivity (>1 x 10/sup 8/ ohm-cm) gave better and more reproducible response to gamma rays when themore » sample was electroded parallel to the growth axis. The high resistivity portion of a crystal is usually found near the quartz deposition plate. By cutting away the cadmium sulfide of this area for a distance of 5 mm froin the seed plate the crystal resistivity is reduced more than 50%. It was found that the dark quenched resistivities of cadmium salfide crystals after remaining in the dank for several weeks were greater than the dark quenched resistivities obtained immediately after quenching with infrared. All crystals tested were of tbe same thickness, 2 mm. The voltage gradient applied was the saine for all samples, 175 volts/cm of length A Co/sup 60/ field of 1 r/hour, 7 r/hour, and 10 r/hour was used in the test series. a fourteen samples tested in the 1 r/hour field, the two crystals having the fastest rise times, namely, 1 minute and 1 minute and 10 seconds, were froin different runs but contained almost identical solute impurities. The two doping agents were indium and zinc with a concentration of 0.05 to 0.1% zinc and with a concentration of 0.004 to 0.005% indium. Each of these crystals also had the fastest response to visible light with 20 milliseconds rise time for 90% saturation for the better sample. (For preceding period see NP-6716.) (auth)« less

Authors:
; ;
Publication Date:
Research Org.:
Eagle-Picher Research Labs., Miami, Okla. Page(s): 43
OSTI Identifier:
4300379
Report Number(s):
NP-6815
NSA Number:
NSA-12-012575
DOE Contract Number:  
DA-36-039-SC-73270
Resource Type:
Technical Report
Resource Relation:
Other Information: DA Project No. 3-99-00-100. Orig. Receipt Date: 31-DEC-58
Country of Publication:
United States
Language:
English
Subject:
PHYSICS; ALUMINUM OXIDES; CADMIUM SULFIDES; CLEANING; COBALT 60; CONFIGURATION; CONTAMINATION; CRYSTALS; DOSEMETERS; EFFICIENCY; ELECTRIC POTENTIAL; ENRICHMENT; GAMMA DETECTION; HEAT TREATMENTS; IMPURITIES; INDIUM; LIGHT; MEASURED VALUES; PREPARATION; PULSES; QUARTZ; QUENCHING; SILICON OXIDES; SILVER; SPECTROSCOPY; TUBES; ZINC

Citation Formats

Powderly, J E, Bean, K E, and Medcalf, W.E. ed. RESEARCH ON GROWING OF CADMIUM SULFIDE CRYSTALS FOR DOSIMETER PURPOSES. Quarterly Report No. 4 for the Period January 17, 1958 to April 17, 1958. United States: N. p., 1958. Web.
Powderly, J E, Bean, K E, & Medcalf, W.E. ed. RESEARCH ON GROWING OF CADMIUM SULFIDE CRYSTALS FOR DOSIMETER PURPOSES. Quarterly Report No. 4 for the Period January 17, 1958 to April 17, 1958. United States.
Powderly, J E, Bean, K E, and Medcalf, W.E. ed. 1958. "RESEARCH ON GROWING OF CADMIUM SULFIDE CRYSTALS FOR DOSIMETER PURPOSES. Quarterly Report No. 4 for the Period January 17, 1958 to April 17, 1958". United States.
@article{osti_4300379,
title = {RESEARCH ON GROWING OF CADMIUM SULFIDE CRYSTALS FOR DOSIMETER PURPOSES. Quarterly Report No. 4 for the Period January 17, 1958 to April 17, 1958},
author = {Powderly, J E and Bean, K E and Medcalf, W.E. ed.},
abstractNote = {Studies were made of the growth of cadmium salfide in alumina tubes replacing tbe quartz tubes previously used. The objective was to decrease the contamination of the cadmium sulfide with silica. Spectrographic analyses of the unvolatilized cadmium sulfide charge in the alumina tubes showed a much lower concentration of silicon, and the deposited cadmium sulfide single crystals also contained less silicon, although the deposition plate was polished quartz. Studies of the single crystals produced in this apparatus have not yet been sufficiently evaluated to state conclusively the effect of a lower concentration of silicon. The two crystals having the best properties from the standpoint of gamma-ray detection had a silicon concentration of 10 to 20 ppm which is less than the normal concentration. By the use of a secondary deposition plate durian crystal growth the total recovery of usable crystalline cadmium salfide was increased to 83% of theoretical. Studies of optimum seeding conditions indicated that the presence of a small amount of either zinc or silver improved the seeding characteristics of the cadmiuin sulfide. It was found that cadmium sulfide crystals of high resistivity (>1 x 10/sup 8/ ohm-cm) gave better and more reproducible response to gamma rays when the sample was electroded parallel to the growth axis. The high resistivity portion of a crystal is usually found near the quartz deposition plate. By cutting away the cadmium sulfide of this area for a distance of 5 mm froin the seed plate the crystal resistivity is reduced more than 50%. It was found that the dark quenched resistivities of cadmium salfide crystals after remaining in the dank for several weeks were greater than the dark quenched resistivities obtained immediately after quenching with infrared. All crystals tested were of tbe same thickness, 2 mm. The voltage gradient applied was the saine for all samples, 175 volts/cm of length A Co/sup 60/ field of 1 r/hour, 7 r/hour, and 10 r/hour was used in the test series. a fourteen samples tested in the 1 r/hour field, the two crystals having the fastest rise times, namely, 1 minute and 1 minute and 10 seconds, were froin different runs but contained almost identical solute impurities. The two doping agents were indium and zinc with a concentration of 0.05 to 0.1% zinc and with a concentration of 0.004 to 0.005% indium. Each of these crystals also had the fastest response to visible light with 20 milliseconds rise time for 90% saturation for the better sample. (For preceding period see NP-6716.) (auth)},
doi = {},
url = {https://www.osti.gov/biblio/4300379}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Oct 31 00:00:00 EST 1958},
month = {Fri Oct 31 00:00:00 EST 1958}
}

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