Lnd Helium 3 Neutron Ludlum Geiger Counter Radiation Detector Tube 3he Rare Htf

US $203

La Valle, Wisconsin, United States
Jun 9th

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FREE WORLDWIDE SHIPPING! Almost impossible to find item! The tube pictured is the EXACT tube offered for sale, tested, and is in good working condition. It is offered from my personal stash of uber rare electronic goodies to some of you researchers and fusor builders out there. It is a highly pressurized (20 bar!) helium 3 neutron detector tube, LND model 25169. Shown is the tube you are getting with it's spec sheet noting the Voltage Neutron Descrimination (geiger mode). In the other pictures are the various test sources used to test it, and the tube itself in a simple moderator under various test conditions. As you can see the tube is relatively insensitive to even screaming gamma, yet is very sensitive to neutrons when adjusted properly. Look how the tube barely responds at all to about 1uCi Cs-137 in a radio SVP tube. This radio tube makes just about any normal geiger tube peg the needle in the first two ranges. One millimeter of lead might as well be window screen to the neutrons from the test source, and 1mm of cadmium foil stops almost all of those sneaky neutrons. The high gas pressure inside this neutron detector tube is what makes it such an extremely sensitive detector for it's size. This tube operates at about 1100 volts happily detecting the neutrons generated from a small AmBe test source. The source is made of an ultra high purity beryllium laser mirror blank with several Am-241 smoke detector sources taped to it. To set this neutron detector tube up for counting properly, you will absolutely require a high quality geiger counter instrument or NIM bin. You are NOT going to run this with a CDV-700 or cheaply made Russian or Chinese counter! You will need a meter with a tightly regulated and adjustable HV power supply good to at least 1,200V and an ELECTROSTATIC volt meter to verify the actual voltage delivered to the tube anode with. For portable use, I recommend Ludlum models 2, 3, 12, and 16. A counter with a window function can help you set the most accurate detection threshold and allow you to operate the tube in the proportional gain region. These helium 3 tubes like a little bit of moderation, but nowhere near as much as a BF3 tube will want. I recommend a minimum of 5mm of HDPE with about 1mm thick lead foil wrapped around the actual tube itself for general purpose use. When compared to my 6Li(Eu) scintillators coupled with a nice ADIT PMT, this 3He tube has several times the sensitivity while being specific for neutrons. Unlike most of the other neutron detectors on ebay, this is an American made, genuine geiger-muller tube from a extremely legit company that is as good as it gets in the art of GM tube manufacture. These are so incredibly rare they are almost impossible to find on the surplus market. In fact, even NEW ones are back-ordered from the supplier for at least 6 months. If that isn't bad enough, they will sell one to you only if you can prove you have an urgent and mission critical need for them! I didn't even want to know how much they are charging for one, my guess is somewhere way north of a grand. Note: The test sources, geiger counter, electrostatic volt meter, or metal samples are NOT included in the sale. You are getting the LND detector tube, the spec sheet, and the moderator/shipping tube only! I have lots of other nuclear interest, lasers, and other unique scientific items for sale this week.