The 9" sphere is used is because it is supposed to most closely replicate the response in tissue (quality factors and energy), over a wide range of energies. This means you don't need to know the exact energy in your power plant fields and say it has a true dose (rem) response and is often called the Remball. Using a smaller sphere would not produce the same response, so you'd need to know something about the energy to know if a correction had to be made. Some have two spheres of different radii and use the ratio to calculate the response. Don't know the energy response or how the ratio algorithm works, but you wouldn't use these size spheres without some form of correction.
We also have the REM500B TEPC for comparison with dosimetry results. It collects spectrums, bins them over 256 channels, and applies quality factors from ICRU-19, ICRP-21, and NCRP-38 all published in 1971, which is what is in 10CFR20 today. ANSI N13.11 also says the TEPC is the proper transfer instrument for demonstrating traceability to NIST. Most techs don't like it because the way the instrument collects a spectrum and then updates the display, the techs aren't sure if the variance in the display is due to the update logic or their change in orientation. They have to survey very slowly or keep going back and forth due to the step changes in the display. The analogue needle and higher detector count rate make the Remball response more smooth and preferred. Glen Vickers Exelon Corp RP Technical Lead, CHP 815-216-2723 (work/cell) From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Friday, July 25, 2014 7:19 PM To: [email protected] Subject: Powernet: Update: What neutron meters are you using? Several of you answered this question back in 2012, but I'm looking for an update. What neutron dose rate meters are you using these days? Our techs want to know how much polyethylene everyone else is carrying around containment. Thanks for your time! Heather Jackson, CHP, RRPT Sr. Health Physicist Palo Verde Nuclear Power Plant 623-393-6076 --- NOTICE --- This message is for the designated recipient only and may contain confidential, privileged or proprietary information. If you have received it in error, please notify the sender immediately and delete the original and any copy or printout. Unintended recipients are prohibited from making any other use of this e-mail. Although we have taken reasonable precautions to ensure no viruses are present in this e-mail, we accept no liability for any loss or damage arising from the use of this e-mail or attachments, or for any delay or errors or omissions in the contents which result from e-mail transmission. This e-mail and any attachments are confidential, may contain legal, professional or other privileged information, and are intended solely for the addressee. If you are not the intended recipient, do not use the information in this e-mail in any way, delete this e-mail and notify the sender. -EXCIP
