ASTM_D_2954_-_71_1984_scan.pdf

900927b 0009399 364 rMntRIcp.DN,.Dt)ANSVASTM D 2954-71(Reapproved 1977)REAPPROVED 8 4 Standard Test Method for ABSORBED GAMMA AND ELECTRON RADIATION SULFATE DOSIMETER DOSE WITH THE FERROUS SULFATE-CUPRIC This Standard is issued under the fixed designation D 2954;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.1.Scope 1.1 This method covers the preparation and use of the ferrous sulfate-cupric sulfate dosim-eter for measuring absorbed gamma and elec-tron radiation dose.I.2 Ferrous-cupric sulfate dosimetry is used for accurate measurement of the absorbed dose in water irradiated with X or gamma rays or high-energy electrons.It is based on the process of oxidation of ferrous to ferric ions by ionizing radiation.The method is most accurate for absorbed doses in the range from 2 x IO5 to 8 x lo5 rads,using spectropho-tometric measurement of the ferric ion con-centration.It can be used to measure doses as low as 6 x 10 rads,with decreased accuracy.2.Summary of Method 2.1 The change in absorbance(at a given wavelength)of an irradiated solution of fer-rous sulfate-cupric sulfate is measured in a temperature-controlled spectrophotometer.Since the absorbed dose in rads in the solution is proportional to the change in absorbance(optical density),it can be determined by mul-tiplying the change in absorbance by a suitable conversion factor.3.Significance 3.1 Absorbed Dose-This dosimeter pro-vides a means for measuring the radiation dose absorbed in a solution that is equivalent to the dose absorbed in water.Conversion to the absorbed photon dose in other materials should be in accordance with the procedures of ASTM Recommended Practice D 2568,Calculation of Absorbed Dose from X or Gamma Radiation.*3.2 Dose Rate-No effect on accuracy of measurement of radiation dose is observed with dose rates between 20 rads/s and loe rads/s.3.3 Temperature-The reliability of the method is not significantly influenced by a variation of the temperature of the system between 20 and 60 C during irradiation.How-ever,at O C,the G-value is approximately 12 percent higher than at 25 C;this leads to an erroneously high value for absorbed dose.3.4 Energy Dependence-The response of this system(here defined as change in absorb-ance per unit absorbed dose in solution),has been shown to be independent of energy in the range from 0.1 to 10 MeV.4.Definition 4.1 rad-the recommended unit for re-porting absorbed radiation dose,defined as 100 ergs of energy absorbed per gram of spec-imen.5.Interferences 5.1 The use of organic stoppers,organic tubing,or metal tubing for sealing or transfer-ring any of the solutions should be avoided,since contact between the solutions and any organic material or metals can lead to erratic results.This system is extremely sensitive to organic impurities even in trace quantities.5.2 Glassware used should be kept ex-tremely clean.6.Apparatus 6.1 Spectrophofomefer-Beckman Model DU,hydrogen lamp attachment,with I-cm matched quartz cells,or equivalent apparatus This method is under the jurisdiction of ASTM Committee E-IO on Nuclear Applications and Measurement of Radiation Effects.Effective March 18.1971.Annual Book of ASTM Standards,Part 35.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.m 9009276 0009400 70b m equipped with a temperature-controlled cell compartment should be used for absorbance measurements.6.2 Containers:6.2.I Chemically Resistant Borosilicate Glass should be used to hold the reagents.6.2.2 Irradiation Containers for the dosim-etry solution should have approximately the same dimensions and geometry as those em-ployed to hold the specimens for irradiation.If the specimen containers are metal or or-ganic,a thin-walled glass liner,1.0 to 1.2 mm in maximum thickness,should be used inside the container(5-ml,quick-break,sealed glass ampoules or equivalent containers are recom-mended).6.2.3 Dosimetry Containers and other glassware may be cleaned by filling them with ferrous sulfate-cupric sulfate solution,irra-diating them to a dose IO”rads,and then rinsing thoroughly(three times)with fresh dosimetry solution.7.Reagents 7.1 Purity of Reagents-Reagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all re-agents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society,where such speci-fications are aailable.Other grades may be used,provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.7.2 Distilled water used in this method shall be free of organic impurities.Use triply dis-tilled water for all dosimetry solutions if pos-sible.Deionized water or commercially avail-a