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NRFneversail
USA
22 Posts |
 Posted - 04/28/2012 : 19:59:09
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Ok, I got my Alpha tube and had tried another way of mounting it 180 the other direction but decided on this set up with the tube on top of the two rubber pads supplied in the Kit and then quick tied it in place. With one smaller clip and one larger, I made the connections so they were on top. The screen to protect the mylar window is a home water faucet airiator screen (I think these are possibly made of stainless steel) that I placed a few dabs of clear silocone rubber around the edges to glue and secure it in place. The 6107 tube is very close to but not touching the protective screen.
I did try the M4011 tube in this Geiger and it seems to be a sensitive GM tube unshielded to an Americium 241 source. AM 241 is primarily an Alpha particle emmiter but also gives off some Gamma ray and so that may be why some people are claiming this tube detects Alpha when in fact, it's really the Gamma. Except for soft tissue like eyes or body organs, Alpha will not penetrate the metal or glass of the M4011. When this AM 241 is exposed to the 6107 tube mylar window (uncovered but protective screen in place), it sends it completely in to a frenzy of clicks over that of the M4011 tube responce. When nothing is covering the window, it is even much more sensitive and further away from the source. The 6107 open window is extremely and amazingly sensitive for how small the area of the window is. When the side of the 6107 metalic tube is exposed to the AM 241, there is a ruduced responce but that would be because the Alpha is unable to penetrate the metal and so the Gamma from the AM 241 is causing the activity at that point. I would expect the M4011 and the 6107 unshielded to become excited by high speed Beta particles but I'm not so sure about the low speed Beta except for the open window end of the 6107. Low speed Beta is easily shielded even by clothing and we even wore simple plastic face shields to minimize eye soft tissue exposure to Beta.
Just based on my former Rad Worker experience, one of these Geigers equiped with a M4011 or a 6107 tube may not make them precision radiation survey instruments but either or both would certainly alert a person that something is changing on the low radiation level end of things as long as these are not themselves, crapped up with radioactive contamination. I'm uncertain what the CPM limits are on the GMC-080's ability to read them or at what point these tubes would become saturated but I would consider having two of these Geigers, one with one tube and the other with the other on hand. I've had this 6107 tube running continuous for 24 hours now and it is delivering the CPM rate of anywhere from 5-13 and is what I would expect for my location based on a radiation survey instrument.
It is a fun basic Count Per Minute instrument and for the cost compared to the real traditional calibrated radiation survey instruments I've used in the past, I am quite amazed with the little Rascal and what it will do. Something I will play with next is a simple Counter I some time ago came across that is used for walking distance calculation. With only a little modification, a Pedometer is turned in to a useful CPM Counter and has a reset button. All you need from there is a Clock/Watch to time your CPM as it records them. It beats trying to count the CPM yourself. I will try and get pictures of it up when I get done and if it works here.I don't see why it won't though.
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Edited by - NRFneversail on 04/29/2012 07:14:50
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GMC-080 w/6107 tube
