Jones, the moral of the story is that the large amount of lead (and it probably took a whole lot for the HPGe detector) converted some of the cosmic rays into a small *neutron* flux. MFMP did not measure neutrons. The Lugano evaluation only made intermittent spot checks for neutrons - they found an increase near the reactor and they had no lead.
People who are making sensitive gamma reading use lead - a lot of it generally. I am building an enhanced cave that has a thick outer layer of lead, and inner layers of Fe, boric acid, and Al before the NaI detector. This should help remove spallated neutrons, and the characteristic x-rays from lead. So, Russ, how did you solve that problem? Did you erect a neutron shield between the lead and the neutron detector? On Sun, Feb 28, 2016 at 7:23 PM, Jones Beene <jone...@pacbell.net> wrote: > Thank you for confirming this detail. For some reason, it seemed not to be > getting though. > > Get rid of the lead and the signal will disappear. > > -----Original Message----- > From: Russ George > > Many years ago in the early days of cold fusion I was running an > experiment at Los Alamos. We had a high quality Germanium gamma detector > and a neutron detector. The neutron detector was old but good though it > printed it's data counts onto a paper tape. It had been calibrated in > another lab down the hall from the lab I was working in. We wheeled it into > my lab and placed it near ( 2 meters away) my deuterium palladium fueled > sonofusion experiment which was known to produce prodigious amounts of 4He, > (prodigious = e16 atoms in machines sensitive to e9 atoms.) > > No one had paid much attention to the neutron detector and its big box of > spirals of paper tape that had the counts recorded. In a lull in work on > the sono-fusion machine I paused to look at the paper tape counts. They > were very simple having just a time code and a counts per minute recorded > on each line. Every minute the machine would type out a new line of data. > As I peered at the tape I noticed that the count rate had gone up suddenly > by 1-2 orders of magnitude. Yikes I thought and with the other guys in the > lab we stepped outside of that lab and down the hall just to put some > distance between us and the experiment while we talked it over. We phoned > the labs top neutron guy whose counter we were using and I told him what > was happening. His immediate response was 'get out of that lab', I told him > we were already calling from a phone down the hall. He came over > immediately and once having briefed him he and I ran quickly back into the > lab so I could show him the counts on the tape and back out again. > > Well he said that's a lot of additional counts but not so high as to be > terribly dangerous. We should think about it a bit. He then walked to the > door of the lab and peered in. Ah Hah he exclaimed I see the culprit. In > the cornor of the lab, 15 feet from the detector, was a very massive block > of lead that was used to encase the Germanium detector when it was in use. > It was sitting on a wheeled cart. "That hunk of lead is catching cosmic > rays and kicking out neutrons", he said. "Let's get it out of the lab and > see what happens." Sure enough we wheeled the lead out of the room and that > was that the count rate in the neutron detector went right back down to > normal background. When we looked carefully at the paper tape and time > codes we could see the count rate had gone up when we moved the detector > from its home lab to our 'lead heavy' lab. No one had looked at it until I > had done so and there was no mark as to the switch of labs. We were all > well acquainted with looking for radiation from many cold fusion > experiments and had not seen any up to that time. > > Moral of the story is radiation measurements are so wonderfully sensitive > one can be fooled by what appears to be large signals but which are really > such tiny signals many simple explanations can explain them away. > > -----Original Message----- > From: H LV > > Subject: Re: [Vo]:Bremsstrahlung radiation > > Jones Beene wrote: From: H LV > > >> In the Lugano test dosimeters were used to check for gamma/xray > emissions at more than 50 cm from the reactor... over the 32 day duration > test it looks like the dosimeters didn't record anything above > background... If the MFMP reactor resembles the Lugano reactor why didn't > the dosimeters register any radiation? > > > > > > I may sound like a broken record on this but it is fairly obvious: > remove the lead bricks - the "apparent" radiation goes away. No lead at > Lugano. > > > > The operative difference was the bricks. The lead captures muons which > are documented by the adjoining scintillator as gamma radiation. Some of > the muons are cosmic but some can be produced in the Holmlid effect. > > > > This can be easily tested next time around: remove the lead - the > apparent radiation goes away. In a thesis which was referenced earlier on > the known muon interaction with lead: > > >
