Step 3.
Place the assembled charger in the carrying case and
fasten the flap.
2.
Dosimeter Recharging and Leakage Testing.
To prevent excessive leakage of charge, dosimeters must be recharged
after not more than two or three days of use (preferably every day).
They must also be recharged when the total dose reaches or exceeds 500
cGy, on the scale. Recharging times are normally designated in the
unit standing operating procedures (SOPs).
NOTE
If the dosimeter has not been charged for an extended
period of time (or has been stored in an uncharged
condition) and is then fully charged, excessive leakage may
occur. This excessive leakage is due to insulation soak-in
(penetration of part of the charge into the insulation).
Do not perform a leakage-rate check on the dosimeter until
it has been charged to 0 for five consecutive days. Ignore
the daily leakage that may occur during this period.
The charge that is placed on the dosimeter will gradually leak even
though the dosimeter is not exposed to X-rays or Gamma Rays. This
leakage, if excessive, will cause an improver reading on the dosimeter
during use. The leakage should not be more than 2 percent of full-
scale reading per day for a good dosimeter. Check the leakage rate as
follows:
Step 1.
Charge the dosimeter to read 0 on the calibrated
scale.
Step 2.
Store the dosimeter in a radiation-free area for a 24-
hour period.
Step 3.
Note the reading on the calibrated scale of the
dosimeter. This reading represents the leakage rate
in either a cGy or Gy (mrad x 1- = Gy)
NOTE
If the leakage rate reading for a period of one day is
difficult to determine, the charged dosimeter may be
allowed to set for several days until a readable value can
be obtained. When the reading is obtained, divide the
total reading by the number of days that the charged
dosimeter was allowed to set to obtain the average daily
leakage rate.
IS0345
5-12
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