Facility for non-destructive analysis for major and trace elements using neutron-capture gamma-ray spectrometry

NGD cold-neutron prompt gamma-ray activation analysis spectrometer at NIST

“…An instrument for thermal neutron (TN)PGAA, in operation since 1978 [1], was upgraded in 2000 to improve detection limits, increase sensitivity, and reduce the fast neutron and gamma-ray components of the beam [2]. This instrument has found important applications in the certification of H, B, and other elements in standard reference materials (SRMs).…”

“…The addition of a cold source and neutron guides to the NCNR in 1990 created beams with significantly longer wavelengths (hki [ 5Å typically at most instrument locations in the newly-constructed cold neutron guide hall). A cold neutron (CN)PGAA instrument, located on the lower half of neutron guide NG7, came into operation in 199 [1,3] and was upgraded in 1995 when the original D 2 O ice cold source was replaced by a liquid hydrogen cold source [4,5]. The CNPGAA instrument has better detection limits for hydrogen (\5 mg/kg in many matrices) and better sensitivity for several other elements than does the TNPGAA instrument.…”

Analysis of archaeological samples by the internal monostandard method of PGAA

“…1 As the analytical sensitivities of the stated elements are remarkably high, this simultaneous multielemental analysis has been utilized complementarily with INAA currently in use. 2 In addition, the less stringent restrictions of the shapes and sizes of samples analyzed can be pointed out as another advantage of the method. Because a sample box is attached to a neutron guide tube extended from a nuclear reactor, there has been possibility to analyze quite voluminous materials; however, PGAA as well as INAA has conventionally been applied only to small thin samples 3 because of the problems characteristic of voluminous samples: neutron absorption and scattering and ,/-ray absorption within the analyzed sample itself.…”

Sensitivity Variation for H, B, Si, Cl, Ca and Cd in Solid Materials by Prompt Gamma-ray Analysis with a Special Emphasis on the Presence of Hydrogen

“…TNPGA measurements at the National Institute of Standards and Technology (NIST), USA were performed on the roof of the reactor using neutron beam directed from the reactor core, yielding a relatively high proportion of fast neutrons as well as background gamma-rays, which originated in the reactor core or the beam tube. 7 In the PGA system at JRR-3 of Japan Atomic Energy Agency (JAEA), the cold and thermal neutrons are guided out from the reactor core by using super mirror tubes of various curvatures, which considerably reduces the proportion of first neutrons and background gamma-rays. In this study, in order to determine the elemental compositions of hydrogenous geological and cosmochemical samples as accurately as possible by PGA, the neutron-scattering effect caused by the matrix H in such samples was evaluated through analyses of the chemical reagents and geological reference materials for both TNPGA and CNPGA by using cold and thermal-neutron guided beams of JRR-3, respectively.…”