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R Knight, J. Lawrence Livermore National Laboratory, Area 300 27 August 2001 Page 2 DTSC PERSONNEL PRESENT Jo Ann Knight, Hazardous Substance Scientist, Leader Alan Jessen, Industrial Hygienist INSTRUMENTS USED A Ludlum 19 gamma detector (serial number 169629) was used. It uses a sodium-iodine crystal, activated with thallium, type scintillation detector to measure the gamma rays. When gamma rays pass through the sodium iodine crystal, visible light is produce and detected by a photoelectric detector. This instrument can only detect gamma rays. It is capable of measuring down to one NR. This instrument is calibrated annually and was last calibrated March 2001. During the inspection, personnel wore SAIC Radiation Dosimeters. The SAIC dosimeters measure gamma radiation exposure doses over time and are set to alarm if the rate of radiation exposure exceeds 2 mR/hr or a total dose of 2 mR is accumulated. Geiger-Mueller (GM) tubes are used to detect the radiation. GM tubes use a chamber filled with a gas in an excited state due to an electric current being passed through it. When gamma radiation passes through this excited/ionized gas, there is a measured change in electrical current. This measured change in electric current is used to quantify the gamma radiation exposure. Three SAIC units were used, serial numbers D12580, D12585, and D12588. These instruments are calibrated annually and were last calibrated March 2001. A Ludlum 3, survey meter, with model 44-9 alpha-beta-gamma (pancake) detector, was also used. This instrument's serial number is 122521 and was last factory calibrated in February 2001. This instrument uses a Geiger-Mueller (GM) detection tube. It is able to detect all three forms of radiation by.using a thin window mica screen behind a 79% open beryllium copper screen. A MiniRAEG photo ionizing detector (PID), serial number 3606, was used. It operates by using ultraviolet light (UV) to ionize (remove electrons) from constituents present in the air. The free electrons produce an electrical current that is measurable and directly proportional to the number of electrons produced and is read as relative response units (RRU). The UV lamp used was 10.6 eV. It will ionize anything with an ionization potential less than 10.6 eV. This instrument was manufacturer calibrated in April 2001 and daily calibrated just before the site visit on the day of the visit. 1