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Lab Surveys FAQs
 
Q. What types of surveys do we need to perform and when do we need to survey?
A. Each user group will need to survey weekly or monthly, depending on the amount of activity used per experiment, and document these results.  Typically, if less than 200 uCi of activity (any isotope) is used per application, monthly documented surveys are required.  Anytime greater than 200 uCi is used, weekly surveys will need to be performed.  There should be no more than 30 days in between monthly surveys, and no more than 7 days in between weekly surveys.  All authorizations that use or store RAM in unsealed form are required to perform and document wipe tests.  Authorizations that contain any gamma emitter(s) in unsealed form are also required to perform and document survey instrument readings at all the same locations.
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Q. Does Radiation Safety perform the required lab surveys?
A. No.  Because of the size of our institution and the number of groups we service, we do not have the staff to perform the required surveys of every lab.  Each group is responsible for performing and documenting their own surveys, with a frequency dependent on the levels of use.  Radiation Safety does conduct "confirmatory" surveys on each authorization during every inspection.
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Q. What if I have no radioactive materials of any kind in my lab? Do I have to survey?
A. If your lab's radioactive materials authorization is currently on "active" status, and you are approved for radioactive materials in unsealed form, you are still required to perform documented lab surveys.  This must be done at least monthly, and must include both wipe AND meter surveys.   The areas to be surveyed are: all designated "break rooms" (individually, not batched together); all RAM-approved drains; and at least five other areas in the main lab (excluding break rooms and RAM sinks).   These final five locations should be rotated every month, so eventually a greater portion of the lab will be surveyed.  In order to have this survey requirement suspended, your AU's authorization must first be officially placed on "inactive" status.  You may contact Radiation Safety at 314-362-3476, or visit the " Authorizations" FAQ section of this website, for information on "inactive" status.  To view the 2005 survey policy change notice, click here.
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Q. I never had to survey before when we didn't have any RAM in the lab.   Why the change?
A. Unfortunately, Radiation Safety is finding that during periods of non-RAM use or storage, many Authorized Users (AUs) and radiation workers begin to neglect certain responsibilities, such as: maintaining survey meter calibration and battery life; assuring access to and proper set-up of a liquid scintillation counter; and ensuring lab member competence in the use of both of these types of equipment.  Because AUs with "active" authorizations have the ability to order RAM at any time, it is imperative that they demonstrate ongoing capability to perform the required contamination surveys and recordkeeping.   In order to have this survey requirement suspended, your AU's authorization must first be officially placed on "inactive" status.  You may contact Radiation Safety at 314-362-3476, or visit the "Authorizations" FAQ section of this website, for information on "inactive" status.  To view the 2005 survey policy change notice, click here
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Q. How do I convert from cpm to dpm?
A. This conversion is necessary, as we are required by our NRC license to document wipe test results in dpm.  Many counters will do the conversion for you.  If yours does not, you'll need to do the conversion manually before recording results.   Following is the formula to use to convert cpm to dpm:
dpm = cpm - BKG
  efficiency
As you can see, you will need to count a background vial (be sure it is in the first position IF your LSC has first position background subtraction!) and know the efficiency of your liquid scintillation counter (LSC) for the isotopes you're counting.  Many LSC operating manuals will list this information.  If yours does not, you can use the following common efficiencies:
P-32 (95%)
S-35 (80%)
H-3 (50%)
C-14 (60%)
For more assistance in determining efficiencies, please call Radiation Safety.
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Q. Do I have to purchase my own LSC and/or Geiger counter?
A. No.  All labs using radioactive materials must have access to the applicable type(s) of survey equipment, but the equipment may be shared with another research group if, at all times, it can be readily accessible to any and all who need it.
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Q. What kind of Geiger counter should I buy?
A. Radiation Safety recommends the use of Ludlum model 2 or 3.  The type of probe can be customized to your needs, but a pancake probe is a good, general-purpose probe that makes surveying areas quick and easy.
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Q. Where can I purchase a Geiger counter?
A. Please review the document Survey Meter Suppliers for a list of manufacturers that sell survey instruments.
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Q. What do I do if my Geiger counter needs repair?
A. First, contact Radiation Safety.  We can do minor repairs.   If any repair is beyond the scope of our capabilities, we will refer you to a repair vendor.  To directly contact a repair vendor, please refer to the document Survey Meter Repair Vendors .
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Q. What types of LSC cocktail can I use?
A. We highly recommend using only non-flammable (or non EPA-regulated) scintillation cocktail.  A list of approved cocktails is provided for your reference.  Please contact Radiation Safety at 2-2996 if you should have need for a cocktail that is not on this list.
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