gnome@oliveb.UUCP (05/02/86)
"Where's Chernobyl? Well, make a left at that cloud and follow the glow..." A friend of mine and I were talking about radiation and Geiger counters one day at lunch when he mentioned that he had an old, grey military radiation meter. He got it surplus a long time ago and never got it running because it uses two very strange batteries. Anyway, he brought it into work the next day and I brought in the unit that I use for detecting Radon gas under houses. We were comparing the relative sizes of the two units when I noticed that the background count (cosmic rays, whatever) had almost doubled. Being suspicious, I thought "maybe this unit (the military meter) had been used in a army weapons test and was contaminated!". Well, after probing around, I found that the meter face and especially the meter needle-tip was coated in radioactive glow-goo that ran my meter to 80% full scale! I have a hard time understanding why a Geiger counter manufacturer would paint the meter with radio-active paint! Oh well. I guess that the military meter was so insensitive that any output from the glow-goo was ignored by the unit. The meter's scale was divided into three segments "safe to travel", "limited exposure", and "take cover..." If you have one of these, put it out in the garage, Radon gas is no fun! Gamma Dose Rate Meter Radiacmeter IM-179 Nuclear Corp of America Denville, New Jersey Contract NO. AF 41 (608)18554 US
ron@brl-sem.ARPA (Ron Natalie <ron>) (05/04/86)
In our Civil Defense kit we have one Gieger counter and two hand held meters that are callibrated in 0-5 Roentgens. Excuse me, but I'm not going to carry that meter anywhere where I can get a reading that will move the needle. -Ron
silber@batcomputer.TN.CORNELL.EDU (Jeffrey Silber) (05/06/86)
I am a volunteer firefighter in my spare time, and all NY State fire
departments have a radiation kit which has a geiger counter and a
bunch of dosimeters. Most of them have a range of 0-5 roentgens, and
believe me that is preferable to the ones where the range is 0-200!
The present teachings indicate that a one-shot, once-a-year dose of
5 roentgens will do no harm. We are also taught that a once-in-a-lifetime
emergency dose on 25 roentgens is permissible with little ill effect.
What made us laugh was where they said that "in times of national emergency
firefighters may be expected to have a one-month cumulative dose of 200
roentgens." The 200 figure is what is considered the maximum sub-clinical
exposure. Above that one would be expected to show at least some hematologic
signs of radiation poisioning.
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A million here, a million there ... they all add up.
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Jeffrey A. Silber silber@devvax.tn.cornell.edu
Business Manager JAS@CORNELLD
Center for Theory & Simulation {decvax,ihnp4,cmcl2,vax135}!cornell!devvax!silber
in Science & Engineering 265 Olin Hall
Cornell University Ithaca, NY 14853cramer@kontron.UUCP (Clayton Cramer) (05/07/86)
> In our Civil Defense kit we have one Gieger counter and two hand held > meters that are callibrated in 0-5 Roentgens. Excuse me, but I'm not > going to carry that meter anywhere where I can get a reading that will > move the needle. > > -Ron By the time you need your Civil Defense kit, worrying about 5 roentgens is a little late. Seriously, 5 REM (sort of vaguely equivalent to 5 roentgens/hr. for an hour) is not lethal, and unlikely to cause sickness in most people. Anyone know where I can get a survey meter in the 0-500 roentgen range for a reasonable price? Clayton E. Cramer
donch@teklabs.UUCP (Don Chitwood) (05/07/86)
Using radioactive paint on the dial of a geiger counter makes perfect sense to me. You would always have a reference (tho probably uncalibrated) right at hand to check the unit's operation. Don Chitwood Tektronix, Inc.