[NewCandle] further adventures of pixie 23

[Horace Heffner]

On Nov 11, 2009, at 3:41 PM, Nick Reiter wrote:

> Hello all,
>
> A bit of an update for this evening, on the last aluminum roll  
> hydrolysis reactor, "Pixie 23".
>
> As you might recall, this is the version in which the hydrolyzing  
> salt solution consists of ~.12M uranyl acetate in H2O, with .03%  
> D2O added...
>
> When I last reported, the primary puzzler was the interesting rise  
> in count rate as seen by a fixed GM tube, when the U solution  
> wicked into the roll turns when the rolls were placed into the  
> bucket.  The emission from the bucket rose from about 300CPM to  
> about 600CPM.
>
> Over the two andf a half weeks that have followed, the foil rolls  
> began to eventually generate H2 gas and before the thick bubbling  
> began to drop off, we hydrolyzed maybe around 1.25l of water.   
> During the time of gas evolution, the emission count rate read by  
> the Geiger counter would fluctuate, sometimes taking on what may be  
> a diurnal patter, ranging between 450 cpm to 600cpm, with late  
> evening readings being higher in most cases than morning readings.
>
> Over the time, as bubbling dropped off, so did the overall count  
> rate, until at about T+10 days or so, we were back down to almost  
> the starting cpm BEFORE the foil rolls were added - 250 to 300cpm.
>
> Yesterday evening, as things really seem to be pretty quiescent  
> now, I carefully lifted out the foil rolls, allowing them to drip  
> dry on a "safe cloth".  The background emission from the solution  
> in the bucket remained at about 300cpm.  That being established,  
> though, I slid the bucket out of the way, and brought one of the  
> rolls (side) up to the GM head.  Very strangely, the rolls were  
> "hot".  At about 4cm distance from a roll side, we see between 1000  
> and 1500 cpm!  One by one, I placed the rolls back into the liquid  
> bucket, and repositioned all.  Back to 300cpm...
>
> somewhere in all of this there is a mechanism - anomalous or not.   
> But to me its giving some brainhurt for now.
>
> Any thought aspirin out there?
>
> nr


Again, I would suggest neutron activation:

   27Al + n -> 28 Al -> (2.25m hl) 28Mg + beta + 4.624 MeV

   28Mg -> (21 h hl) 28Na + beta + 1.83 MeV

   28Na -> (30.5 ms) 28Ne + beta + 13.9 MeV

but also my CRC shows this branch:

   28Na -> (30.5 ms) 27Ne + beta + n + 2.389 MeV gamma + energy

which has an 11.9% probability, and which has the potential to  
increase the neutron flux. It also drags out the decay time, because  
12 percent of the neutrons generate more neutrons about 21 hours  
later.   The gammas have the potential to generate more neutrons  
right off from spallation.

When you pull the foil out of the water the geiger counter can pick  
up the extra betas. That might be verified with different thickness  
screens, i.e. with different beta path lengths.

My guess is the Al still has some U in it or on it now.

Gee, I wonder if the initially high gamma flux caused splitting of  
the deuterons into P + n, or neutron spallation off the 28 Ne?  If  
you could build up enough 28 Mg, 28 Na and 27 Ne it could sustain its  
own chain reaction?  From each initial neutron comes 4 high energy  
betas, plus at least one gamma plus 12% neutrons, plus Bremsstrahlung.

Probably not.


Best regards,

Horace Heffner
http://www.mtaonline.net/~hheffner/