Dosimeter...

I have a question for the gang across the pond.

Is anyone familiar with the pocket dosimeter from the late 1950's, early 1960's?

To be more specific, the "Direct Reading Pocket Ionization Dosimeter" AKA "Quartz Fiber Dosimeter" manufactured by the RA Stephen & Company, Ltd. of the UK.

Here's a photo of what they look like.

Before my time working in radiography, what do you want to know?

looks like the antique version of what they have today. looks like it clips into a pocket or button line. after the prescribed time it is sent into the lab to get the reading. today they are lightweight and about the size of a small political campaign button. they still are sent into the lab...

View: https://www.youtube.com/watch?v=HdsLuOumwJE

Confirm that it's the type that would have been issued to Royal Observer Corps members in the early 60's in the event of a nuclear exchange. The ROC role had shifted very significantly from the one it had during WW2 which was aircraft tracking from surface observer posts - instead the posts moved underground and were capable of sustaining 4 Observers for several days. The equipment in the posts included a BPI (Bomb Power Indicator) which measured the pressure developed by a blast, a 4-film pinhole camera which would produce a spot indicating the location and height of the blast, and a continuous radiation monitor which helped to track the spread of fallout. All this information would have been reported to the Group HQ by landline.

Members on duty would have been issued with these dosimeters - they were effectively capacitors that were charged up and the charge would decay in the presence of ionizing radiation. Unless the blast occurred very close to the post the radiation danger was from fallout and the exposure was really for the guy who had to shin up the ladder, access the camera, remove the films and then get back underground. There was a procedure for recording the dosimeter readings. Every so often the unit had to be recharged as the charge in the unit would dissipate with time. I spent about three years in the ROC in my late teens

pbehn said:

Before my time working in radiography, what do you want to know?

Click to expand...

Would you beleive that I am actually looking for two of those vintage RA Stephen types?

On a side note, the one that bobbysocks mentioned is the type I am personally familiar with...but the pocket-pen type is one I am searching for.

I have an old CD ( civil defense ) Geiger counter you can borrow if you want....you can go hunting uranium in the desert or see if that nasty nuke plant down the street is giving you a glowing personality....

When I was in the USAF in 66, I was stationed at Seymour Johnson, AFB in N.C. I worked in a bomb dump right next to the nuclear storage area.
We had to carry a small round black plastic device, about 1.5 diameter, by 1 inch thick, in our brest pockets at all times. It had a screw cap on it with some type of film inside. I can't remember how often we turned them in, and replaced them with a new one. I was there just 6 months.
I've still got one here in my old junk.

I've wondered if that was a way to check on possible leakage from what was stored next door, or if it was a way to check our exposure if the base suffered a nuclear strike.

I am sure that is probably what it was. unless the tube was made of lead, any rays from the nukes would have an affect on undeveloped film. the higher the speed the film the more sensitive it is.

I used pen dosimeters about 20 years ago. They was replaced for EPD´s. They had two very thin sheets of metal, one fixed and the other could turn around a hinge. Before use, they was charged whit static electricity. Every single gamma photon discharged the sheets in more or less the same amount. This way, the force due to static electricity was gradually smaller and the movable sheet moved towards the fixed one. An optical set plus a proper scale converted position of sheet to mrems. If accidentally it fell, the read was completely lost, so, you didn´t knew your dosis until TLD read was made.
Edit: I have two of them, completely out of order, into my desk.