FOIA: Development of a directional thermal neutron detector system

THERMAL_NEUTRON_DETECTOR_SYSTEM.pdf
Development of a directional thermal neutron detector system
Describes the development of a portable, thermal neutron detection system for nuclear monitoring. Design, development, fabrication and testing are outlined.
Document date: 1996-07-01
Department: Advanced Technology Development Center, Northop Grumman Corp.
Author: Robert L. Schulte, Martin Kesselman, Frank R. Swanson
Document type: report
pages: 78


Archivist's Notes: Fair to good quality document. Unclassified.

The overview from the Stormingmedia (cost $8.95)

...here again this document on ATS with no costs involved

Abstract: The development of a portable, thermal neutron detection system for nuclear monitoring is described. The report outlines the design, development, fabrication and testing of a prototype directional thermal neutron detector. The system is a battery powered unit that contains 12 detector modules. Each module consists of a thin gadolinium foil convertor layer sandwiched between two planar, large area, quad silicon detectors and the associated analog electronics to process the 8 detector channels for each module. Two additional modules contain a tantalum convertor foil used for compensation of the gamma ray response. The digital electronics uses gate arrays as counters which are read and controlled by a microcontroller unit. Neutron and gamma ray count rates and directional indicator quotients are displayed to determine the presence and direction of the radiation source. Design criteria, operational features and system test results are reported along with recommendations for system designs based on this technology.

This document is linked to the Vela incident:
FOIA: Detection of Regional Seismic Events using a Small Broadband
FOIA: Evolution of some geophysical events on 22 Sep 1979 - Tiros-N satellite
FOIA: Defense Technical Intelligence Report for the 22 Sep 1979 Vela Satellite event




[edit on 1-12-2007 by frozen_snowman]

This document is linked to the Vela incident:

Interesting as the Vela Satellite was made to detect nuclear explosions. In 1980 an independent panel of experts concluded that the event was probably small but close to the satellite as opposed to large event far away.

Did the Vela Satellite detect a small nuclear explosion conducted secretly by South Africa? What else could it have been..

What about UFO powering up at close range? If one considers that UFOs may use a neutrino reactor to generate thrust, then perhaps there was another explanation never considered by the gov't... or at least never made public. Sources of neutrinos are nuclear reactions caused by our sun, man-made, cosmic rays, or (perhaps) UFOs using a neutrino reactor? Check out this link for more on a hypothetical neutrino reactor..

so basically, what all of this is saying;

is that the gov't has the Capability of monitoring the location of nuclear devices?

so, in reality , if a nuke went off in a city, we could hold the gov't accountable for at least negligence, due to the existance of said technology

i find this so useful and wonderful a technology, i would have every county in the nation and every ally updating their defense networks immediantly.

it only seems prudent to spend billions on this type of defense. any sane military would have put alot of eggs in this basket, so to speak

at least i would, because i dont like being suitcase nuked.

just some questions i was wondering about, but then agian
maybe i shouldnt be asking lol!

Argh, so much misinformation, so little time.

1) A neutron detector is not a neutrino detector. We will never have a portable neutrino detector. The ones that exist are immense stationary things deep in caves filled with ginormous tanks of water or other fluids. They take data for months to years.

2) There have been neutron detectors for quite a while now, it is an important subject. The original application is technology for verification of arms control agreements. The idea is that you can put one up to your 'adversary's weapons and verify whether or not there is a fissile warhead inside without getting additional information about its construction.


For detecting nuclear weapons in a terrorist scenario you would need to have multiple kinds of detectors and a good model. You would need to detect neutrons, possibly gamma decays and other "byproducts" from cascading nuclear reactions inside the device as one particle hits another atom and so on. The quality and specific details of the nuclear materials themselves matter as well as contamination from other substances and shielding.

A plutonium-based weapon will be detectable at longer ranges since it has greater spontaneous fission and emissions. Modern boosted weapons also have a bit of tritium in them which decays with beta decay.

Certainly today specific details about technology and capability for remote nuclear weapon and material detection is highly classified for the obvious, very good, reasons.

A pure U-235 (e.g. Hiroshima) weapon is certainly the most difficult to detect remotely as it has the lowest spontaneous fission rate, which is in fact exactly why it is the easiest weapon design to make. The Hiroshima bomb was never tested, it was just computed to work the firs ttime and it certainly did.

For a nuclear weapons state, more complex plutonium implosion weapons are superior since they are easier to make small and light for missile use, and once you pay for the infrastructure and don't give a crap about nasty reprocessing waste and environmental stuff, the plutonium is cheaper in quantity.

For a terrorist, a pure-U-235 gun-type bomb on a shielded truck (e.g. deuterated paraffin and other stuff) is the thing.

reply to post by mbkennel


hi mbk,
Thanks for pointing that out. What about the Vela Satellite decting neutrons and not neurtrinos? If a hypothetical neutrino reactor existed you would need to generate neutrinos by changing protons into neutrons.

Or you can chalk it up to S. Africa or perhaps India testing nukes. Also the panel mentioned another possibility in which a tiny meteor struck the satellite and debris reflected sunlight into the sensors.