Fluke Biomedical 451B - Manual (Page 16)

451B
Operators Manual
6
Specifications
Radiation Detected ............................................... Alpha above 7.5 MeV, beta above 100 keV, gamma above 7 keV
Operating Ranges ................................................. 451: 0 mR/h to 5 mR/h, 0 mR/h to 50 mR/h, 0 mR/h to 500 mR/h, 0 R/h
to 5 R/h, 0 R/h to 50 R/h
451-DE-SI: 0 µSv/h to 50 µSv/h, 0 µSv/h to 500 µSv/h, 0 mSv/h to
5 mSv/h, 0 mSv/h to 50 mSv/h, 0 mSv/h to 500 mSv/h
Accuracy ................................................................ ±10 % of reading between 10 % and 100 % of full-scale indication on
any range, exclusive of energy response (Calibration source is 137 Cs)
Detector ................................................................. 349 cc volume air ionization chamber; phenolic chamber wall
246 mg/cm2. Chamber window is composed of 6.6 mg/cm2 Mylar. A
coating of graphite has been applied to the walls to make them
conductive. The collection potential is -63 Volts. The Chamber is
vented through the desiccant
451B-DE-SI: In order to achieve energy response consistent with
measurements of H*(10) as required by ICR4-47, aluminum has been
added to the back wall, 38 % of the side wall area, and to the beta
slide. With the Beta Shield open, the 451B can measure skin dose at
H* (0.07), and Deep Dose H* (10) with the Beta shield closed.
Warm-Up Time ....................................................... Less than one minute for initial operation
Response Time ..................................................... Time measured from 10 % to 90 % of final value for a step
increase/decrease in radiation rate such that a range change does not
occur:
451B: 0 mR/h to 5 mR/h, range: 8 seconds. 0 mR/h to 50 mR/h, range:
2.5 seconds. 0 mR/h to 500 mR/h range: 2 seconds. 0 R/h to 5 R/h,
range: 2 seconds. 0 R/h to 50 R/h, range: 2 seconds
451B-DE-SI: 0 µSv/h to 50 µSv/h, range: 8 seconds. 0 µSv/h to
500 µSv/h, range: 2.5 seconds. 0 mSv/h to 5 mSv/h, range: 2 seconds.
0 mSv/h to 50 mSv/h, range: 2 seconds. 0 mSv/h to 500 mSv/h range:
2 seconds
NOTE: Instantaneous exposure rate is limited to 50 R/h (0.5 Sv/h),
including but not limited to a pulsed field.
Precision ................................................................ Within 10 % of reading
Readout .................................................................. Liquid Crystal Display: Contains an analog bar graph with a permanent
scale on the display and a 2 ½ digit display. Analog Display: The bar
graph consists of 100 segments, 2 ½ inches long; the scale has five
major divisions; the appropriate value for the operating range of the
instrument will appear below the scale. Digital Display: The digital
display is 2 ½ digits followed by a significant zero digit depending on
the operating range of the instrument. The leading ½ digit is blank, or a
“1” or a “0” for clarity. Units of measure appear to the right of the digital
display. Appropriate multipliers also appear on the display units: As
indicated under Range, programmable in R/h or Sv/h
External Controls .................................................. ON/OFF button, MODE button.
Automatic Features .............................................. Ranging and zeroing are fully automatic.