Do you have a reference on this? Otherwise, a lead cave would not be useful - it is there to protect the sensor from the cosmic rays.
My understanding is that the cosmic rays produce the neutrons by spallation. If the neutrons are absorbed in the lead, they will likely cause isotopic shift which will lead to beta emission and then characteristic x-rays for lead at 78 keV. My plan is to follow the inside of the lead with 1/4" of Fe which will absorb all of the 78 keV but will produce the characteristic x-ray of Fe at 6 keV. Then there is the boric acid neutron absorber, and then the aluminum absorbs the 6 keV from the Fe, but gives off 1.5 keV Al characteristic x-ray in small amount. On Sun, Feb 28, 2016 at 7:58 PM, Jones Beene <jone...@pacbell.net> wrote: > *From:* Bob Higgins > > Ø 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. > > Bob, as the thesis clearly states – the neutrons then are absorbed by the > lead, causing the gamma radiation. > > > >
