APPENDIX IV
Laboratory Equipment Needed in Early Phase
(a) Gamma Spectrometry Equipment will be required to determine the
composition of the release by testing air sampling media, and to test the composition of radioactivity deposited on the ground and on crops by measurements on samples.
The coaxial germanium detector with multichannel analyser and data logger specified in the Evaluation of Equipment Specification Report will be suitable for analysis of air sampling media. Arrangements should be made for pre-programming it for the most important gamma-emitters expected in an accidental release (see Table 3.1) and for nuclides used for calibration. The gamma spectrometry equipment must be calibrated to deal with relatively high levels of the relevant nuclides, and the sample geometry for filters from air-samplers, and for the selected radio-iodine absorbers (silver zeolite cartridges, or activated charcoal absorbers 'Maypacks').
(b) Beta Counting Equipment
Measurement of gross beta particulate activity on air sample filters will be required. A suitable shielded detector and scaler should be provided in the Radiation Laboratories. This equipment is not specified for the background radiation monitoring programme.
(c) Thermoluminescent Dosimeter Processing
A high throughput of thermoluminescent dosimeters from personnel and from fixed stations must be processed during an emergency.
If alpha spectrometry equipment is available it would be used to measure Pu-239 and Pu-240 in environmental samples during the recovery phase of the emergency. However, this equipment is not considered essential since during the early and intermediate phases the presence of other nuclides is likely to determine countermeasures, and, during the recovery phase, expertise and equipment from outside Hong Kong could be called on.
It will be essential for the laboratory staff to exercise strict control to avoid cross-contamination of samples. All sample containers should be placed in a sealed outer bag immediately after collection of the sample, and this outer protection should be changed when the sample is transferred to the laboratory.
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