In reply to Jones Beene's message of Fri, 11 Dec 2009 08:03:53 -0800: Hi, [snip]
I think the main problem here is that there is only a significant cross section for alpha emission when the neutron is fast. In fact, alpha emission upon absorption of a slow particle is a form of fission, and only seems to happen with either very heavy or very light nuclei. Pd is pretty much in the middle of the table. I thought a possible example might be Be7 + n => 2 He4 however this reaction has a cross section of about 1 barn for slow neutrons, whereas the ejection of a proton instead i.e. Be7 + n => Li7 + p has a cross section (for thermal neutrons) of about 100000 barns (huge!). The cross section increases for exothermic reactions as the neutron temperature drops. >Mark, Horace > >In the original context of that posting, the problem is this. When Pd >adsorbs a neutron and becomes activated, Pd (n,a) there should be a >detectable secondary gamma. > >BTW - this process would typically leave ruthenium, which is often seen in >transmuted electrodes. In fact, years ago Passell found gammas, of an energy >from the known ruthenium isotope emission spectrum, but that is one of those >papers that was never replicated. > >Usually gammas are nearly absent in LENR, certainly less than the excess >heat would indicate. That is why the suggestion was made that the UCN might >not "act like a neutron" in the sense that even though the kinetic energy >(which the UCN lacks) is small, in comparison to a typical ~1 MeV gamma, >this could simply be an indication that it falls short of some unknown >threshold, which still allows alpha emission, but at lower kinetic energy. > >Of course, in the sense of the virtual neutron, quasi-neutron, hydrex or so >on, of the older theories - where the activating particle is stated as "not >a real neutron" there is less of a problem ... > >...except in lack of documentation ;-) > >Jones > > > >-----Original Message----- >From: Mark Iverson > >Horace wrote: >"I don't know why a neutron would not act like a neutron." > >Let me take a stab at that one... >Perhaps because it's in a fully D-loaded palladium lattice, where other >things aren't acting like >they 'should'? ;-) Yeah, I know, that wasn't much help... > >-Mark > > >-----Original Message----- >From: Horace Heffner [mailto:hheff...@mtaonline.net] >Sent: Thursday, December 10, 2009 6:27 PM >To: vortex-l@eskimo.com >Subject: Re: [Vo]:Falsifiability of cold neutrons in LENR > > >On Dec 10, 2009, at 12:21 PM, Jones Beene wrote: > >> -----Original Message----- >> From: Horace Heffner >> >>> That of course assumes the W&L claim that "neutron is thus absorbed >>> within about ten nanometers" is valid.... >> >> As you go on to imply, that particular version is almost certainly not >> valid, due to NA, and is probably "undergoing revision" as we speak >> ... ;-) but of greater interest would be this: >> >> Is there a version of the broader UCN dynamic, using published >> characteristics of the same instead of a tailor-made invention, which >> stands up better to criticism and do involve NA ? >> >> This might go back many years. The weight of evidence for helium in >> LENR, based on known reactions prior to 1989 together with lack of >> ~24 MeV gamma - still favors alpha release from Pd via adsorption of a >> neutron - and a subthermal neutron and with activation fits the bill >> if it will emit no gamma ... > >I don't know why a neutron would not act like a neutron. > Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/Project.html
