Fast neutron activation dosimetry with TLDS

Technical Report · Wed Jan 01 04:00:00 EST 1975

DOI:https://doi.org/10.2172/7345241· OSTI ID:7345241

Pearson, D. W.; Moran, P. R.

Fast neutron activation using threshold reactions is the only neutron dosimetry method which offers complete discrimination against gamma-rays and preserves some information about the neutron energy. Conventional activation foil technique requires sensitive radiation detectors to count the decay of the neutron induced activity. For extensive measurements at low neutron fluences, vast outlays of counting equipment are required. TL dosimeters are inexpensive, extremely sensitive radiation detectors. The work of Mayhugh et al. (Proc. Third Int. Conf. on Luminescence Dosimetry, Riso Report 249, 1040, (1971)) showed that CaSO/sub 4/: DyTLDs could be used to measure the integrated dose from the decay of the radioactivity produced in the dosimeters by exposure to thermal neutrons. This neatly combines the activation detector and counter functions in one solid state device. This work has been expanded to fast neutron exposures and other TL phosphors. The reactions /sup 19/F(n, 2n)/sup 18/F, /sup 32/S(n,p)/sup 32/P, /sup 24/Mg(n,p)/sup 24/, and /sup 64/Zn(n,p)/sup 64/Cu were found useful for fast neutron activation in commercial TLDs. As each TLD is its own integrating decay particle counter, many activation measurements can be made at the same time. The subsequent readings of the TL signals can be done serially after the induced radioactivity has decayed, using only one TL reader. The neutron detection sensitivity is limited mainly by the number statistics of the neutron activations. The precision of the neutron measurement is within a factor of two of conventional foil activation for comparable mass detectors. Commercially available TLDs can measure neutron fluences of 10/sup 9/n/cm/sup 2/ with 10 percent precision.

• Research Organization: Wisconsin Univ., Madison (USA). Medical Physics Labs.
• OSTI ID: 7345241
• Report Number(s): COO-1105-227
• Country of Publication: United States
• Language: English

Related Subjects

440102* -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ACTIVATION DETECTORS
ALKALINE EARTH ISOTOPES
BARYONS
DOSEMETERS
DOSIMETRY
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
FAST NEUTRONS
FERMIONS
FLUORINE 19
FLUORINE ISOTOPES
HADRONS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
LUMINESCENT DOSEMETERS
MAGNESIUM 24
MAGNESIUM ISOTOPES
MEASURING INSTRUMENTS
NEUTRON DETECTORS
NEUTRON DOSIMETRY
NEUTRONS
NUCLEI
NUCLEONS
ODD-EVEN NUCLEI
PERFORMANCE
RADIATION DETECTORS
RADIOACTIVATION
SENSITIVITY
STABLE ISOTOPES
SULFUR 32
SULFUR ISOTOPES
THERMOLUMINESCENT DOSEMETERS
ZINC 64
ZINC ISOTOPES