Well guys I called and talked with Mr. Apfell, himself, following Jim's posting of the site URL. I had been there once before about two years ago and was amused, but shy about purchasing neutron counting expendables.
The "Neutrometer-S" bubble detector is, as I thought, a relatively expensive consumable, has a definite lifespan, and can be reused about 10 times. These are, intrinsically, a health physics dosimeter, but they can give unusually accurate readings of fast neuts when used in bunches and then statistically reduced to real dosage.
We had a nice chat regarding my using them for low level d-d fusion counting.
The neutrometer-S is a thermometer like pen device which counts neutrons via bubble counting done by the observer following exposure.
I think they sound great! They will double as a neutron film badge or personal dosimeter as well.
Once they indicate a neutron flux, the clock starts to tick on these babies. They have a 6 month lifespan following the first counting session. If the counting seession exceeds 20 mrem then the life span is curtailed to 30-60 days! They have a new virgin lifespan of 1 year from date of shipment and are prepared for the order and not languishing on shelves.
After exposure, which occurs in the horizontal with the pen laying on its side, you count the bubbles while still horizontal (~8-10 bubbles/mrem) after logging the data, the pen is up-ended in a glass or cup to let the bubbles dissapate and the device is ready for another counting session.
IMPORTANT! They should be stored, both new and used in the fridge in the VERTICAL position only! According to the good Mr. Apfell, with virgin units stored in this fashion, the lifespan can actually go to two years with a fall off in performance of about 10%. Units that have been used are not canidates for extended life with their clocks mindlessly ticking as mentioned above. The website data is for warranty purposes and is underrated. He gave me a lot of tips and hints on beating the website life expectancy figures.
Clustering of three or four of these in a small area will give extremely accurate rates for fast neuts when averaged statistically.
He suggested theire use for D-D fusion rates at low levels to be superb and he has actually used them for same in some early work he did a few years back.
Now to cut to the monetary chase. They will not sell you one. The minimum order is ten and in that quantity, they are $60.00 each! So be ready with $600.00 to begin to play this game. The prices slump to $54.00 each in units of 20. Got a kilobuck and change?
I hazard to suggest a group buy if enough are serious which I seriously doubt. I would be in for 3 of the little suckers, but group buys have gone wrong in the past on a Tesla list I was once on.
The only way such things happen properly is to have every one send a MONEY ORDER order to a central guy who is stalwart and honest and who acts as purchasing agent and distributor. No personal checks and no promises to buy when they are received accepted.
Remember these are time sensitive items which, when done, are trashcan bound.
A lucky purchase of a neutron counter can often be found in the $150.00 to $500.00 range if you know where to look.
Richard Hull
Created on Monday, March 26, 2001 11:25 AM EDT by Richard Hull Last Modified on Tuesday, March 27, 2001 11:49 AM EDT by Richard Hull