A new instrument for activation analysis - The cold neutron irradiator

Conference · Fri Jan 01 00:00:00 EST 1993 · Transactions of the American Nuclear Society; (United States)

OSTI ID:6030771

Clark, D D; Hossain, T Z ^[1]

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1. Cornell Univ., Ithaca, NY (United States)

As part of a program of developing analytical applications of cold neutrons, the authors are undertaking optimization studies of a novel design that exploits the combination of the superior analytical properties of cold neutrons with the simplicity and portability of isotopic neutron sources such as [sup 252]Cf. The basic concept is simple: The capabilities of the usual design in which the neutron source is surrounded with a moderator block with access ports and throughports can be enhanced by cooling the moderator to cryogenic temperatures. A proposed name for the device, which is suitable for both neutron activation analysis (NAA) and prompt gamma NAA (PGNAA), is the cold neutron irradiator (CNI). Results from initial scoping studies are summarized. Comparisons are primarily with a room temperature isotopic source and in some respects with thermal reactors. The most obvious advantage is that neutron reaction cross sections, being proportional to 1/v, are, for example, more than eight times larger for cold neutrons corresponding to the temperature of liquid helium than for room temperature neutrons. Cold neutrons are more readily collimated, guided, focused, filtered, and shielded than thermal neutrons. It is therefore easier to achieve a low ambient gamma-ray background and to decrease the distances between source, sample, and detector to obtain further increases in counting rates or to tailor the geometry to suit differing experimental requirements.

• OSTI ID: 6030771
• Report Number(s): CONF-930601-; CODEN: TANSAO
• Journal Information: Transactions of the American Nuclear Society; (United States), Vol. 68; Conference: American Nuclear Society (ANS) annual meeting, San Diego, CA (United States), 20-24 Jun 1993; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPES AND RADIATION SOURCES
COLD NEUTRONS
NEUTRON ACTIVATION ANALYSIS
NEUTRON ACTIVATION ANALYZERS
DESIGN
CALIFORNIUM 252
CROSS SECTIONS
NEUTRON SOURCES
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ACTIVATION ANALYSIS
ALPHA DECAY RADIOISOTOPES
BARYONS
CALIFORNIUM ISOTOPES
CHEMICAL ANALYSIS
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
FERMIONS
HADRONS
HEAVY NUCLEI
ISOTOPES
MEASURING INSTRUMENTS
NEUTRONS
NUCLEI
NUCLEONS
PARTICLE SOURCES
RADIATION SOURCES
RADIOISOTOPES
SPONTANEOUS FISSION RADIOISOTOPES
YEARS LIVING RADIOISOTOPES
070201* - Radiation Sources- Design
Fabrication & Operation