Frequency of SRD Calibration

[barberj@m4lp.com (Jerry Barber)]

     Happy Holidays Radsafe,
     
     Two HPs at my site disagree on whether or not our Self Reading 
     Dosimeters (SRDs) should be treated as primary dosimeters based on the 
     guidance given in Reg Guide 8.4.  Reg Guide 8.4 states that when used 
     as primary dosimeters these devices need to be calibrated every 3 
     months, while when used as secondary dosimeters, a 6 month calibration 
     frequency is sufficient.
     
     The point of disagreement stems from consideration of what happens 
     when our normal primary dosimeter (TLD) is lost or damaged.  One HP 
     contends that if the SRD is calibrated every three months, then the 
     SRD dose can be used "unequivocally" in providing a dose estimate (the 
     monitored individual is hence wearing two primary dosimeters, if the 
     TLD is lost, just use the dose from the SRD).
     
     The other HP thinks that their is only one primary dosimeter, and that 
     if this dosimeter is lost, the SRD should be used as part (hopefully 
     as a big part) of the ensuing dose estimate which must be performed 
     (see Sandy Pearle's recent post).
     
     Truth often lies somewhere in the middle.  What do Radsafers who work 
     in external dosimetry think (anybody left that uses SRDs!!!)??  FYI, 
     at our site individuals always wear their SRD and TLD if they are in 
     areas where they may receive exposure.
     
     Hopefully posts on this thread will be of interest to the list.  If in 
     doubt, please contact me directly.
     
     Thanks
     
     Jerry Barber
     M4 Environmental
     1000 Clearview Ct.
     Oak Ridge, TN 37830
     barberj@m4lp.com