At 06:03 PM 12/7/2009, Horace Heffner wrote:
On Dec 7, 2009, at 12:43 PM, Abd ul-Rahman Lomax wrote:
In the other direction, most C-12 breakups that occur in the CR-39
are not detected, they must occur within a certain region to be
revealed by the etching.
This is a good point. They are probably throughout the CR-39.
Detecting lots more in the middle might be done by dissolving layers
of CR-39 and re-etching.
They are. Etching deeper into the CR-39 reveals more tracks. Those
would not be alpha tracks....
It's possible that a much more reliable indicator of the neutron
flux would be the far more numerous tracks from knock-on protons.
There are lots more of the low energy neutrons that show up as proton
knock-ons. That is not much in doubt, at least in my mind. You can
see them in the photos on the back side.
That's right. Lots of them.
The triple tracks are
controversial and interesting because hot fusion people see them
plenty. It gets their attention.
Yes. They are glamorous, much more striking that some boring single pits.
Also, they indicate a DT reaction.
As one possibility, maybe the most probable.
That indicates a possible very short lattice half life before fusion
of the T, because there is so little of it. The fact there is any T
at all is of course interesting - if you don't think cold fusion can
occur!
Absolutely. If the T is created by one of the reactions, it would be
hot and would almost certainly fuse with something given where it is
generated, and the most likely target would be a deutron. Presto.
Neutron of the right energy.
An alternative explanation for deep single proton knock-on
tracks could be K0 knock-ons.
Aw, there you go again. Sure. But is there any need to hypothesize
this? Wouldn't the presence of these particles be an even greater mystery?
The K0 can also cause triple tracks by
decaying into a Pi+ ad Pi-, i.e. :
p + K0 --> p + Pi+ + pi-
or just double tracks by:
K0 --> pi+ + pi-
Similarly, the lambda0 can make triple tracks by:
lambda0 --> p + Pi-
There appear to me to be a lot of double tracks, and I haven't heard
a good explanation for that.
I think I have but I don't remember what it is. As to the triple
tracks above, I'd be suspicious, it's unlikely that they would be the
equal tracks we see, consistently.
A powerful magnetic field might pick up the negative particle
byproducts.
I've thought of putting the CR-39 in a strong field, but I don't
think the tracks travel far enough to show an effect.
A bubble chamber would be very handy. I suggested a
cloud chamber with video camera might be of use to amateurs. I also
suggested using stacks of CR-39 to detect kaon decay within a few
inches of the cell.
Yes. A bubble chamber would be way cool, a cloud chamber might
actually be practical for amateur work.
I'm seriously looking into how to put together detector stacks. It
might be possible to obtain very thin CR-39. I'm trying to use
commercial makrolon, and seeing some problems with it, though I'm
finding that I may be able to address these problems with some alcohol.
Basically, drink the alcohol and it all looks much better.
Seriously, it appears that ethyl alcohol in the etch bath can produce
cleaner results. I'm still not sure what I'm seeing with my first
etch experiments (using exposure to Am-241), there are variables I
haven't worked out. I etched for about 7 hours the first time and the
surface was hamburger, it appeared. So I etched two hours, not so
much hamburger, but still a mess. So I etched for one hour, earlier
today, and it started to look like actual tracks, but too many, in
places where no Am-241 exposure had occurred. It did seem from a
quick count that there were more tracks where the exposure had been,
maybe half again as many. I'd have expected a lot more tracks,
though, given how intense the light is from my spinthariscope screen
from this source, I don't have to be much dark adapted to see it. I'm
going to do other stuff, such as trying LR-115, for the LR-115 I have
is fresh. The makrolon, off-the-shelf, could have accumulated a lot
of background.
But then I could pre-etch. And pre-etch with alcohol should leave the
surface relatively smooth. Lots of stuff to try. It would be really
nice if I can get this makrolon to work, but it's 0.010 inch
material. Better than the 1/16 material used by SPAWAR (from the
point of view of depth, not of quality of material). I just found
that I can buy 0.005 material from a source, but ideally there is
someone making this stuff who knows how to optimize it for use for
radiation detection.
Talked to Landauer today. The rep claimed that they don't sell any of
their material, and that all the material they make, they own. I.e.,
they rent it to you, you send it back, and they develop it. That's
obviously not the whole story, and I'm supposed to get a call back
from someone else in the company tomorrow.
I also have some Landauer CR-39 but it's about two years old.
There are filters made from CR-39 by exposing them to radiation and
etching. They can make holes of pretty much any size, for biological
use. The material in some of the work I've seen described was 6
microns thick. That would be ideal, actually. So I'm going to try to
find out how to get some of that.
There is some possibility that mylar can be used for track detection,
I've seen reference to it. But anything that has been sitting around
is going to have background damage on the surface.
