Search found 2329 matches

by Carl Willis
Tue Feb 25, 2003 6:30 am
Forum: Books & References
Topic: Theses on thermal neutron detector construction
Replies: 2
Views: 3536

Re: Theses on thermal neutron detector construction

<t>That's a neat article Jon.<br/> <br/> Actually a bit of work has been done on lithium salicylate as a neutron detecting material. Salicylic acid and its salts are reported to be charged-particle scintillators that function even in aqueous solution, and of course the Li-6 furnishes the required pa...
by Carl Willis
Tue Feb 25, 2003 6:08 am
Forum: Fusion --- Past, Present, and Future
Topic: Fission's on a Roll
Replies: 14
Views: 7358

Re: Fission's on a Roll

Choice of fissile isotope (whether it is U-233, U-235, or Pu-239) actually has relatively little effect on the fission product yields--which peak in the mass 95 and mass 140 vicinity. There is just no way to selectively produce only those very few isotopes that are stable.
by Carl Willis
Mon Feb 24, 2003 10:03 pm
Forum: Fusion --- Past, Present, and Future
Topic: Hydrogen Energy
Replies: 11
Views: 6144

Re: Hydrogen Energy

<t>Garrett,<br/> <br/> The concept of a group effort in which there are centralized facilities, coordinated schedules and sharing of actual expenses / equipment / liabilities by amateurs is, like Hal has mentioned, a supreme organizational challenge. You're right that much great, cutting-edge work c...
by Carl Willis
Mon Feb 24, 2003 6:49 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Neutron reflection - can it be done?
Replies: 14
Views: 4524

Re: Neutron reflection - can it be done?

<t>Hi Mark,<br/> <br/> Free neutrons will not last forever--they have a half-life of about ten minutes, undergoing beta decay! But they can be trapped and even cooled with cryogenic systems so they almost "come to a halt." Although I don't know the details, this is supposed to be very hard to do. Ho...
by Carl Willis
Sun Feb 23, 2003 4:21 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Prompt Neutron Activation Spectrum
Replies: 11
Views: 6294

Re: Prompt Neutron Activation Spectrum

<t>Yep, that's the one. You mentioned the gamma comes "from the recoiling Li-7." Does the lithium nucleus form in an excited state? If for some reason the (a, n) reaction is classed differently from standard neutron capture where the product mass goes up by one, that may explain the omissions of the...
by Carl Willis
Sun Feb 23, 2003 12:29 am
Forum: FAQs: Neutron - Radiation Detection
Topic: FAQ - NEUTRON SAFETY
Replies: 19
Views: 25383

Re: FAQ - NEUTRON SAFETY

<t>Brett,<br/> Indeed there will be a very few SF neutrons from U-238. The branching percentage for this decay mode is some 10^-5 percent, with the usual alpha decay comprising the remaining ~100%. Yields are many orders of magnitude lower for all other naturally occurring isotopes. Interestingly en...
by Carl Willis
Sat Feb 22, 2003 9:59 pm
Forum: Vacuum Technology (& FAQs)
Topic: More Turbo Pump Questions
Replies: 3
Views: 2551

Re: More Turbo Pump Questions

<t>Hi Thomas,<br/> <br/> I'm borrowing what I call a "baby turbo" from Guilford College to run my fusor. While I can run it on my own mechanical pump / trap alone, the baby turbo--with a pumping speed in air of about 60 l / sec--allows higher throughput. It is very simple and easy to run and, aside ...
by Carl Willis
Sat Feb 22, 2003 7:48 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Iodine Activation
Replies: 4
Views: 3580

Re: Iodine Activation

<t>Hi Larry,<br/> <br/> Thanks for the suggestions. Have a few questions though. When you mention bismuth, do you mean the prompt gamma capture peaks or the gammas from decaying Bi-210? Unfortunately bismuth has an abysmally low cross-section and resonance integral.<br/> <br/> About the neutron mult...
by Carl Willis
Sat Feb 22, 2003 6:16 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Prompt Neutron Activation Spectrum
Replies: 11
Views: 6294

Re: Prompt Neutron Activation Spectrum

<t>Hi Jon,<br/> <br/> You're doing what I did, and getting the same search results. I believe the data was omitted or simply not present in the major tables. However, if you search on Google for stuff on boron capture gamma radiation, you get plenty of stuff that cites the 478 keV number...in fact, ...
by Carl Willis
Sat Feb 22, 2003 5:49 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Prompt Neutron Activation Spectrum
Replies: 11
Views: 6294

Re: Prompt Neutron Activation Spectrum

<t>Phil, <br/> <br/> The pulse-height spectrometer essentially sorts pulses collected from a detector according to amplitude. It does this by (1) digitizing incoming pulses; (2)"binning" the pulses by amplitude, e.g. by using a chain of comparators or some more sophisticated method; and (3) storing ...