CAPINTEC, INC.
CRC
®
-712MX
APPENDIX II
TABLE OF CALIBRATION SETTING
NUMBERS
CALIBRATION SETTING NUMBERS
The Calibration Setting Numbers in Table II are applicable to the Capintec Radioisotope
Calibrator only for measurement of isotopes in NIST standard source ampoule geometry.
Special configurations for Brachytherapy source measurements are listed in Table III.
If the calibration setting number is followed by a multiplication sign “
×
” or a division sign “
÷
”
and a number, the meter reading with the Calibration Potentiometer Setting must be
multiplied or divided by the number following the sign.
If the sample contains radioactive impurities, the meter indication will always be higher than
the actual activity of the principal isotope. It will not, however, be the total activity of the
principal isotope and the impurities.
If a Radium Needle is measured, the reading will be lower than the true activity in the needle
due to the shielding effects (filtration) of the needle. To estimate the true activity in a needle,
increase the reading obtained with a calibration number for Ra226 (790) by 2% for each
0.1mm of platinum wall thickness. For example, add 10% to the reading for a 0.5mm wall
platinum needle and add 20% to the reading for a 1.0mm wall platinum needle to estimate
the true radium activity.
ABBREVIATIONS USED IN TABLE II
Abbreviation Meaning Abbreviation Meaning
eqb. equilibrium D
days
S seconds Y
years
H hours E
exponentiation,
i.e.,
M minutes
3E5 = 3
×
10
5
UNCERTAINTY DUE TO SYRINGE CORRECTION
The Calibration Setting Numbers are given for approximately 5 grams of radioactive solution
in a standard source ampoule made of about 0.6mm thick borosilicate glass. The standard
radioactive source in the ampoule is, however, a good approximation for a
radiopharmaceutical in a plastic syringe or a glass syringe (wall thickness about 1.2mm) for
most radioisotopes.
January 08
APPENDIX II
A2 - 1
