May 2010 Transcript of Col Halt tape.

[Daniel]

Storm, do you know how many counts per minute there would be on a reading of 0.35mR or .5? How many would normal background radiation give?

Also roughly around 4m19s on the audio tape there are two high pitched beeps which sound like it was part of the two-radio broadcast. Any idea what it means?

[Storm]

Storm, do you know how many counts per minute there would be on a reading of 0.35mR or .5? How many would normal background radiation give?

Also roughly around 4m19s on the audio tape there are two high pitched beeps which sound like it was part of the two-radio broadcast. Any idea what it means?

Hi Dan,

Counts per min or CPM and Counts Per Second CPS are terms of contamination. For instance if you have somethng radioactive and it leaks onto something or bits rub off it contaminates the area around the object. This remains until cleaned up. Potentially dangerouse with certain isotopes. To test for contamination you use a swab or smear paper. The area that you swab determines the content of the equation used to convert into units of possible dose. The result you get is determined by counting the smear paper in a lead container. The lead reduces gamma penetration and removes alpha and beta penetration of the container. You count the smear for whatever time you feel is right and then devide by 60 to get your CPM. Before any of this you count for 10 minutes and devide by ten to get a background count per minute. The is removed from the result of the smear and is termed in the equation as CCPM corrected counts per minute. So now you have your result and you can then convert into dose units using the equations. CPS is specifically used in measuring surface contamination using a contamination meter. This gives you an instant redout of potential contamination on a surface. Anythng above 5 CPS is considered note worthy and is thereafter smeared for exact results. Because you smear a specific area ie a meter sqaure this gives you a best possible answer to contamination level. As for the radiation readings of the night it is hard to say what they would have got in terms of CPM CPS because radiation meters measure for absorbed dose from an area and that is the microsieverts. Contamination however gives CPS and CPM. I hope that explains. As for the noises I will look tomorrow buddy but there will be a few adjustments to the transcript in the next week because I found something else. Nothing earth shattering yet just another aspect of it.

Take care

[Daniel]

Cheers for the post. So would you feel the clicks in the youtube video from this post is accurate or added in for sensationalism?

Sorry for the questions, guess I'm in a curious mood today

Daniel

[Storm]

Cheers for the post. So would you feel the clicks in the youtube video from this post is accurate or added in for sensationalism?

Sorry for the questions, guess I'm in a curious mood today

Daniel

The clicks are an audibale reference for the operator. The more radiation that passes into the GM tube the more reactions with the quenching gas, the more the resistance of the GM tubes central wire is altered, the more the needle deflects on the dial. The reactions and voltage drop are also registered as sound via some frisky electronics. So in answer to your question, the sounds are acurate for about 30 to 40 CPS. It would go higher if there were more. Turn the dial to the next scale and it accounts for this sound wise. So while on the bottom scale it clicks like hell, turn it to the last scale and it clicks a lot less. Now as for where this ties into the previous question, what would background sound like on that meter, it should sound like silence, and you should hear one or two clicks, every 10 seconds or more. Maybe a little more, maybe a little less. When on the tape, they say, your getting three good clicks, four clicks max, I really do not know what they mean by that. Because you would asses contamination in Bequerelles, and CPS. The clicks are just a confidence thing so you can look away from the dial and look at what your monitoring properly. And if you say, four clicks max, it would be ovre a set period of time. Say a minute. Which they do not do. So clicks meant something else to them. As they have shown totlally expected behaviour in all respects until that. So clearly we do not understand what clicks meant. I think it may mean postions on the dial. Distance is sometimes called Kilometers, but is shortened to Klicks in military terms. Maybe it is something like that. So four clicks max. is literally four little marks on the dial. I have no idea. If that sound audio is a first generation copy, it was quite a bit of radiation. However - if you listen to their voices and assume it was nothing because they were not concerned, I in my job would need to see quite a bit of radiation before I began to be shaken. It all comes down to personal expereince of anything. In my first expereince of air sea rescue I was amazed at how rough and ready everything was. Later It became mundane. Though it is never that in reality. So in radiation terms, thats why you have limits, as benchmarks that you stick to rigidly without fail. I hope that helps.

Craig