A continuous analog informetion, and amenable to autometic data reduction, Cumuletive dose in roentgens mey be plotted by summing the number of dose increments and plotting the running total, using appropriate sccle factors, Dosage rate in roentgens por hour may be plotted by computing, for cach time interval between individusl incroment marks, the quotient of unit dose by time interval. In practice, this will be done by plotting normalized reciprocal time intervals, 3.1.2 Detection Gas ionization chamber dctectors vill be used, The assumptions of the basic plan indicate that records will be required over a& dynamic range of as much as eight decades of dose rate, For the basic region of eight decades, four two decade ranges (A, B, C and D) will be used, Modified stations will be provided by elimination of decade ranges & or D where no significant information is expected in these renges, All ranges vill record simultaneously and continuously. Chamber designs are such that above 95 per cent collection occurs to the limiting intensity for erch chamber, Output indication continues at a fixed rate, independent of dose rate so long as the latter remains higher than 30 por cent above the nominal upper limit, Simultancous deta collection is believed to be in this case a more reliable and simple mcthod then an automatic range chonging scheme, The cost per channel of recording apparatus of the kind proposed is smell in comparison with that of detector range chenging mcens which have been considered, The ion chambers are of cocxial design using from 2 to 10 atmospheres of nitrogen for the various ranges in volumes of 1,8 to 3000 cubic centimeters, Integration capacitances renge from 15 micromicrofarads to 0,01 microfarads. Chambers are hermetically sealed using "O" rings and teflon feed through insuletors. Gas cans are spun aluminum, 3.1.3 Electronotry The function of the electrometer circuits is to provide one closure of a pair of relay contacts each time each ion chanber integrating crpaciter discharges through a fixed voltage difference, This is provided for by using a conventional sprce charge grid electroneter tube in the inverted electrode arrangement. Output curront is taken from the space cherge grid hich is opereted set constant voltage, (modified by a compensating circuit for correction of filement terpereture effect on calibration)end ion chambor signal is put on the control grid. The output current, as it rises through « chosen bias value, reverses the coil current in a moving coil, magnetic contact relay which serves as a discrininator and operates the output relay, The conventional plate of the electrometer tube is used as e gating control electrode over-riding the control grid to provide a fixed delny of about seven S7T, LOUIS F Cc a 3 /oY