Talk:Neutron source

message: I don't know too much about this process, but the title was already there without any text, so I added a couple of lines on it - I'm sure someone more informed can tidy/add more here Rtcoles 16:16, 9 August 2006 (UTC)
thread_title:  Photofission 

message: http://en.wikipedia.org/w/index.php?title=Neutron_source&oldid=236852757#Medium_Sized_Devices
::"Typically these accelerators operate with voltages in the > 1 MeV range,"
This makes no sense; MeV is a unit of energy. Do these accelerators use high voltages in the megavolt range? Or does this refer to the resulting neutron energy, or what? Clarify, anyone? Thanks in advance, 77.183.58.129 (talk) 09:13, 2 October 2008 (UTC)
thread_title:  Clarify? 

message: The article says costs are about $15-$20k. Per what? Microgram? Curie? Please specify. Rwflammang (talk) 18:58, 8 July 2010 (UTC)
replies: text: I cut the problem sentence, reproduced here; The price of a typical Cf-252 neutron source is from $15,000 to $20,000. Circuitboardsushi (talk) 00:03, 26 June 2013 (UTC)
thread_title:  Cost 

message: I wonder what is the number of particles emitted by the different sources. Would be interesting to have some numbers for comparison.  —Preceding unsigned comment added by 83.236.228.234 (talk) 12:24, 9 August 2010 (UTC)
replies: text: That depends on the source, shielding, and moderation. Perhaps such data could be shown in some kind of table.Circuitboardsushi (talk) 00:06, 26 June 2013 (UTC)

text: That information is irrelevant, as sources can be ordered / programmed to generate a huge range of fluxes. Maybe it could be interesting to see numbers of flux/mass for the isotopes, but that wouldn't apply to the devices that generate neutrons.  — Preceding unsigned comment added by 141.246.2.80 (talk) 14:54, 16 October 2013 (UTC)
replies: text:  I think it would be useful to describe relevant characteristics of suitable neutron sources for the various applications listed in the lead: eg. flux rates, and neutron speeds or energies. eg fusion reactor materials testing needs very high flux, ~14 MeV neutrons ? - Rod57 (talk) 03:49, 13 December 2015 (UTC)
thread_title:  Number of Particles/sec

message: Lead/intro makes it sound like this article is only about devices designed to generate desired neutrons (for various applications) - yet the body does not describe the applications (or their neutron source requirements) and does include devices where the neutron emission is a problem to be dealt with. Should we widen the intro - or trim the body ? - Rod57 (talk) 04:18, 13 December 2015 (UTC)
thread_title:  Accidental or deliberate 

message: The section Radioisotopes which decay with high-energy photons co-located with beryllium or deuterium do not say if these are a practical/used way to generate a useful neutron flux. Needs a reference we can check to clarify. - Rod57 (talk) 10:59, 5 July 2017 (UTC)
replies: text: isn't it possible to produce gamma rays (or photons of equivalent energy) from sources other than nuclear decay? If so, would that be a theoretical or even a practicable pathway?  Hobbitschuster (talk) 11:42, 19 February 2022 (UTC)
thread_title:  Theory or practical 

message: Do all these sources generate fast neutrons ? Wireline_(cabling)#Nuclear_tools says they use fast neutrons but this article doesnt mention them. fast neutrons implies the radioisotope neutron sources produce fast neutrons. - Are different sources used for their different neutron energy distributions ? - Rod57 (talk) 11:18, 5 July 2017 (UTC)
replies: text: generally speaking they tend to produce neutrons of much higher energy than thermal. Spallation and fusion produce the fastest iirc while photodisintegration and alpha sources still produce pretty fast ones. Fission neutrons are usually considered "fast" in the context of fission, but they are not necessarily the fastest neutrons that can be obtained at scale. For most applications, however, neutrons of energies higher than those released in fission are of little use. In fact, many research applications even use (relatively) exotic moderators like solid methane to produce cold or ultracold neutrons as they have some interesting properties useful for research. Hobbitschuster (talk) 11:47, 19 February 2022 (UTC)
thread_title:  Which generate fast neutrons 

message: From what I can tell, the "typical" rock or tree will emit essentially zero neutrons per second. Is that true? Or is it maybe 10 or 10 or 1000 neutrons per sec? I know that uranium in trace amounts is wide-spread in clay soils - this is where radon in peoples basements comes from. Does this mean that some clay soils emit neutrons? What's the actual flux?  I know that it's got to be tiny, but how tiny, exactly, is it?  67.198.37.16 (talk) 06:52, 10 January 2018 (UTC)
replies: text: the direction from which you're most likely to get neutrons is above you. There is a tiny fraction of cosmic rays that reaches the surface of the planet in the form of neutrons. Either "primary" (i.e. A neutron somehow flew here before it decayed or interacted with anything) or - much more commonly - "secondary". Those secondary neutrons are the result of both "pedestrian" nuclear reactions (p,n), (n,2n), (γ,n)... And more "exotic" ones like muon capture. Of course most of those "secondary" neutrons are absorbed before they ever reach the ground, but there is a constant low level flux that sufficiently sensitive detectors can pick up on. Hobbitschuster (talk) 11:52, 19 February 2022 (UTC)
thread_title:  Neutron flux in nature? 

message: A discussion is taking place to address the redirect :Cold source. The discussion will occur at Wikipedia:Redirects for discussion/Log/2020 August 24#Cold source until a consensus is reached, and readers of this page are welcome to contribute to the discussion.  Hildeoc (talk) 18:04, 24 August 2020 (UTC)
thread_title:  "Cold source" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]] 

message: Is there much literature on the possibility of nuclear proliferation due to strong neutron sources? Iirc many of the current applications for neutron sources were discovered when the Americans built them as one of several ways to get plutonium only to find out that other applications of their neutron sources were much more promising. However, neutron sources have become more powerful over time and the strongest ones can be "switched on and off", which allows to control the grade of plutonium produced to a very fine degree of precision. Now, a neutron source strong enough to produce significant amounts of plutonium would require a flux equal to or higher than commercial nuclear power plants (which of course also produce plutonium if not necessarily weapons grade) but crucially to have that flux sustained or at least pulsed often enough to produce "enough" (none of that "five millisecond pulses a week" stuff). So first of all: is this a present or future concern? And second: does there exist citable literature on that issue? The two questions can well have different answers as evidenced by the proliferation concerns associated with mostly hypothetical technology (like laser isotope separation) or with pathways that haven't ever been taken in proliferation to date (most prominently the extraction of plutonium from power reactors). And of course it is entirely possible that there is concern "behind the scenes" but nothing quotable... Hobbitschuster (talk) 11:41, 19 February 2022 (UTC)
thread_title:  Proliferation risk