ROM Read-only memory. RSAIT Radiation Safety Audit and Inspection Team. SAC Scintillation Alpha Counter. SATCOM Satellite Communication. SitRep Situation Report. SN Serial Number. SOP Standard (or Standing) Operating Procedure. Sr Strontium. Specifically, the isotopes ®5sr and 99sr. TG Task Group, Tl Thallium. TRU The transuranic elements. Specifically, 238 py, 239 py, 240py, and 241 4m, TWX Teletype ype m message. TTPI Trust Territory of the Pacific Islands. «8 Uranium. Specifically the isotopes 234y, 235y and 238y, USAF United States Air Force. wh, = Uninterruptible Power Supply. 1h UPS Yttrium. Specifically the isotope 9°y, mu ~ Greek alphabet letter used to denote attenuation; also micro rho - Greek alphabet letter used to denote density. (1 a)