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Step 3 of tour Testing and Calibration
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| Arrow-Tech, Inc. does the testing and calibration of our own dosimeters after
they are manufactured. |
| We also can test and calibrate all
makes and models of Direct Reading Dosimeters you may
have. Contact us for pricing and any
special needs you may have. |
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Our Dosimeter calibration consists of the 4
following tests: |
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Electrical Leakage
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| Dosimeters are set to zero and are allowed
to stand for 1 hour, recheck readings and placed in 50 degree Celsius oven for 5
days. They are removed from oven and allowed to cool to room
temps. The Dosimeter is read and recorded. Any dosimeter that has
changed by more than 1.25.5%/Day (ANSI 2.5%/Day) of full-scale reading is rejected. |
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Hermetic
Seal
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Dosimeters are set to zero and placed on
a rack in bell jars and vacuum pumped for 48 hours (vacuum pressure 75 micro
inches of mercury). Then the bell jar is placed in vacuum source and
exposed to a mid scale radiation dose. The dosimeter is removed from
bell jars and the reading is recorded. Any dosimeter reading less than 90%
of Reference Radiation reading is rejected. A record is
kept of whether the dosimeters passed or failed test. |
| Gail starting the Mid Scale test using the 100 curie radiation
source. The Dosimeters are given a predetermined amount of radiation
to read Mid scale. For example the range being checked here is the 600
R. They are being exposed for 20 minutes. The reading on the pocket
dosimeter should read 300R. Those dosimeters that read within + or -
10% are acceptable. Those outside that range are failed. (Customer
calibration) |
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Accuracy
Test |
| Dosimeter are set to zero and placed
in a carousel, then exposed to a
mid-scale radiation dose. The
readings are recorded and any dosimeter that exceeds +/ - 8% (ANSI +/- 10%) of the mid-scale
reading is rejected. Picture shows the 20 curie radiation source inside source
room. |
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| 20 curie Cs-137 source - For testing low range dosimeters. This was
manufactured by J L Shepherd & Associates. |
One of Two- 100 curie Cs-137 source's - For testing high range
dosimeters. This was designed and manufactured by the Oak Ridge National
Labs. especially for Arrow-Tech, Inc. |
| Each source room has a 2 inch thick lead door to
prevent any radiation from escaping during testing. |
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Monitoring station's to view what is being tested inside the source room. There
is a monitor for each source room. |
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| Alarm system in radiation source room |
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Ruggedness Test
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| Pat Jeannotte starting the ruggedness test by pouring the dosimeters
down the stair step apparatus. This shakes any dust or dirt
particles that may be present after the manufacturing process. If
any particles are visible when looking through the dosimeter, the
dosimeter is discarded. |
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| Back
to Radiation Detection Tour Next step 4 of tour |
