Detectors, humidity, etc.

[JPreisig@AOL.COM]

Hmmmmm,



     This is from:     jpreisig@aol.com    .



      Hi Radsafers,



            This is for the person having trouble with his/her counting 

systems,

      due to failure of his/her environmental (temperature, etc.) control 

      systems.  The first thing to do is get your environmental control 

systems

      fixed, and NOW.  You can read your counting system operating manuals,

      and they might suggest how your counting systems behave at various

      temperatures and humidity values.  I remember trying to calibrate my

      neutron multisphere spectrometer at Brookhaven Lab, without paying much

      attention to room temperature.  It doesn't work.  Calibrate at a usual

      (and repeatable) room temperature and you might also want to

      calibrate at the same time each day.



            As for winter versus summer readings, well, radon is "frozen" in 

the

      ground in winter and emanates more freely in spring, summer and fall.

      This could affect your calibrations.  A reference to this seasonal 

radon 

       effect is given in an older version of Cember's Health Physics book.

       I think the original article reference is given there also.



            I know you aren't doing neutron system calibrations, but various

      articles by Eisenhauer and Schwartz (NBS/NIST) and Hunt (England)

      discuss air-scattering effects during calibrations.  One such article is

      in Health Physics (the journal).



            The fun part about doing neutron calibrations at Brookhaven (in 

the

      former Camp Upton military morgue???) is that one will get the 

      counting system working well in the environmentally controlled

      calibration building, and then one drags the counting system to

      the AGS (Alternating Gradient Synchrotron --- a proton accelerator)

      and expects it to work well there.  Unfortunately, it is sweaty, humid

      and nasty over at the AGS (with some cooling with the building doors

      open).  Then some yahoo (my former boss there???) expects you

      to get results at the 5% or less level.  5% to 10 % is doing pretty 

well,

      I think.  What a hoot!!!!



           Good luck with your counting work.  FIX your environmental control

      systems.



           On a lighter note, the Los Alamos Lab web-site has some discussion

      of a satellite being built by the USA, with nuclear reactor propulsion.

      Visit their web-site???



       Take Care.  Enjoy the Olympics.               Joseph R. Preisig, Ph.D.