The Human Monitoring Laboratory's whole body counter: monitoring the liquid nitrogen level as a quality control tool.
The Human Monitoring Laboratory (HML) has developed a method to measure the liquid nitrogen boil-off rate from the whole body counter's single dewar as a function of time. The device consists of a commercially available instrument that was modified to fit the HML's whole body counter's dewar; unfortunately, the modification was not perfect requiring an alternative approach to using the maximum fill value. The boil-off rate is now measured by taking two measurements and calculating the loss rate. Resulting boil-off rates are plotted on a control chart so that long-term trends can be easily assessed.
Human Monitoring Laboratory, Radiation Surveillance and Health Assessment Division, Radiation Protection Bureau, 775 Brookfield Road, PL6302D1, Ottawa, Ontario, Canada K1A 1C1. gary_h_kramer@hc-sc.gc.ca
Gary H
GH
Kramer
Barry M
BM
Hauck
D002170:Canada; D009584:Nitrogen / Q000032:analysis*; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D012996:Solutions; D014915:Whole-Body Counting / Q000295:instrumentation* / Q000379:methods
D012996:Solutions; D009584:Nitrogen