Radiation Survey Procedures
Check gloves frequently when working with radioactive material. Survey work area after each use of radioactive material.
1.Don protective equipment, such as gloves,
before performing survey.
2.Check survey instrument.
3.Perform survey appropriate to the isotope(s)
used. For low-energy beta emitters
(H-3, C-14, S-35, etc.), take swipe samples and count using liquid
scintillation counting. For
high-energy beta emitters (P-32, etc.), take swipe samples and count using
either liquid scintillation counting or a ratemeter + GM probe. Floors and
surfaces can also be directly monitored using a ratemeter + GM probe.
4.If using a ratemeter + probe, hold the probe
window 1 cm from the surface to be surveyed and move the probe over the surface
at a rate of approximately 1 cm/second. If surveying for alpha or beta
contamination, do not put plastic or parafilm over the probe window, as alpha
and lower-energy beta particles will not be able to reach the probe window.
5.Make sure to check the most common sites for
contamination, such as survey meter, soap/towel dispensers, drawer handles,
refrigerator/freezer handles, chair edges, writing utensils, survey record
books, floors, radio dials, telephone receiver/keypad, microwave oven touch pads/handles,
and non-radioactive trash containers.
6.Record survey results in survey record. Use the
radiation safety survey form for your records.
Check
battery -
Turn the switch on the
ratemeter to "BATT" or flip the "BATT" switch to
"ON."
The needle on the meter face should move to a position within or beyond the indicated area on the meter face scale.
Replace batteries if needed before use of the
ratemeter.
Check
speaker -
If there is an audio switch on the ratemeter,
turn it to "ON."
Set the ratemeter to a scale of "X1."
The ratemeter should "chirp" or
"click."
If the speaker does not
function, the survey meter can be used, but the surveyor will need to check the
reading on the ratemeter face frequently.
Check
background -
Go to an area with an expected low background
rate.
Note the count rate when the ratemeter is
switched to the "X1" scale.
The background rate will vary from as little to 10 counts per minute up to several hundred counts per minute.
Do not use the survey meter if it does not
register a background rate.
Check
probe -
Hold the supplied check source up to the probe
window. There is a 50 ml falcon
tube with a check source inside.
Do not open the tube. The
check source is found in Hagen 104 in the side room.
Note the counting rate. It should be between 300 and 425 cpm/min at the 1x setting.
Do not use the survey meter if the counts per
minute registered does not fall within +/- 20% of the expected reading for that
check source.