halk The samples are ashed at 500 to 550° © in electrically-heated mffle furnaces which hold individual racks, The ashing process is accelerated by feeding in about one liter of oxygen per minute to each furnace and requires slightly under one hour for completion, After cooling, the ash is transferred to a 1-1/4" diameter plastic counting planchet. Each planchet has been labeled with a gummed label which is a duplicate of the one used on the data card. This maintains the proper continuity and agreement of serial numbers, The planchets are then sealed between two layers of vinyl tape in groups of eighty, The i oy sealing is done with a high frequency heater which makes a ring seal around each planchet, The samples are spaced about 9" on centers and the resultant tape can be readily handled in an automatic counter. Each tape contains four blanks consisting of unexposed papers run through the process and four counter standards, Counter background is de- termined from the blanks and counter efficiency and reliability is determined from the standards, cere a 1 Counting The samples are analyzed on automatic beta counters with Geiger tube detectors, A reel of eighty planchets is loaded into the counter and the first sample is positioned above the Geiger tube which is mounted face up, The sample is separated from the tube face by a single thickness of vinyl tape and is held in position by a fixed stop which engages the side of the planchet, The counts are registered on a four Dekatron scaler, Simultaneously, 600 pulses per minute are applied to this scaler and are recorded on a duplicate parallel scaler. When 10,000 count plus time pulses are recorded on the first scaler, the number of time pulses is punched on paper tape by a Data Transfer and Recording (DTR) system developed by the Instrumentation . bes 4 F F F } k k } b pe } rp b k be r be ees - 33 - 6