SELECTIVE RADIOACTIVATION AND MULTIPLE COINCIDENCE SPECTROMETRY IN THE DETERMINATION OF TRACE ELEMENTS IN BIOLOGICAL MATERIAL. MEASUREMENT OF MANGANESE

Journal Article · Tue Aug 01 04:00:00 EDT 1961 · Intern. J. Appl. Radiation and Isotopes

DOI:https://doi.org/10.1016/0020-708X(61)90151-X· OSTI ID:4840945

Borg, D C; Segel, R E; Kienle, P; Campbell, L

Coincidence spectrometric techniques frequently can resolve the radiations from complicated mixtures of radioisotopes by capitalizing on differentiating characteristics of the pertinent decay schemes. When isotopes with distinctive beta - gamma decay chains are selected for detection, scintillation spectrometry may be employed. Then the gamma spectrum from a NaI(TI) crystal can be recorded by a multichannel pulse-height analyzer that is gated by a coincidence circuit when it simultaneously receives signals from the gamma -counter and from a beta scintillation spectrometer. When used in this way, the power of a two-crystal beta - gamma detector to resolve a single beta - gamma decay branch is limited by the gamma response of the beta sensing element, which thus records interfering gamma - gamma cascades. A marked improvement in selective beta - gamma discrimination is provided by a three- crystal coincidence geometry, where an additional plastic or anthracene crystal (which is so thin as to have negligible gamma sensitivity) is placed in front of the thicker crystal of the beta spectrometer to distinguish beta from gamma rays. When radiometric analysis is applied to neutron-activated sources, detection of certain nuclides with low-energy (n, gamma ) resonances (e.g. Mn/ sup 55/, Co/sup 59/) may be further enhanced relative to other isotopes without such resonances (e.g. Na/sup 23/, Cl/sup 37/) by irradiating with resonance neutrons. In an example of neutron activation analysis of manganese, selective activation with a filtered reactcr neutron spectrum and triple coincidence spectrometry were combined. The former enhanced the ratios of Mn/sup 56//Na/sup 24/ and Mn/sup 56//Cl/sup 37/ act ivation to about seven times and fifteen times, respectively, the values prcduced by thermal neutrons; while the latter suppressed by a factor of about 100 the interference due to Na/sup 24/ in the detection of Mn/sup 56/ by gamma spectrometry. In this way, manganese in blood plasma may be measured without recourse to radiochemical separations. (auth)

• Research Organization: Brookhaven National Lab., Upton, N.Y.
• NSA Number: NSA-15-029142
• OSTI ID: 4840945
• Report Number(s): BNL-5012
• Journal Information: Intern. J. Appl. Radiation and Isotopes, Journal Name: Intern. J. Appl. Radiation and Isotopes Vol. Vol: 11
• Country of Publication: United States
• Language: English

Related Subjects

ACTIVATION
ACTIVATION ANALYSIS
ANTHRACENE
BETA SPECTROMETERS
BIOLOGICAL MATERIALS
BLOOD PLASMA
CHEMISTRY
CHLORINE 36
CHLORINE 37
COBALT 59
COINCIDENCE METHODS
CRYSTALS
DECAY
GAMMA RADIATION
GAMMA SPECTROMETERS
MANGANESE
MANGANESE 55
MANGANESE 56
MEASURED VALUES
NEUTRONS
PULSE ANALYZERS
QUANTITATIVE ANALYSIS
RADIATION SOURCES
RADIOISOTOPES
RADIOMETERS
RESONANCE
SCINTILLATION COUNTERS
SODIUM 23
SODIUM 24
SODIUM IODIDES
SPECTRA
SPECTROMETERS
THALLIUM
THERMAL NEUTRONS
THERMAL RADIATION