Neutron-Induced Prompt Gamma Activation Analysis (PGAA)

Development of boron calibration via hybrid comparator method in prompt gamma activation analysis

“…For the light elements composing each sample matrix, gamma-ray self-absorption is negligible, especially as the samples are positioned at 45° with respect to the incident neutron beam and high-purity germanium (HPGe) detector face. Based on these assertions, for a given set of experimental conditions, the net peak area A x from a neutron capture gamma ray of energy E c from element x, can be expressed as a product of constant terms [3,9]:…”

“…(1). Using the definition of the partial elemental capture cross-section σ x γ,E γ [3], and rewriting the bracketed terms as the number density N x of element x since the mass density ρ x of any element x is known, Eq. (1) can be written as:…”

“…A chief contributor to this variation is thought to be 135 Xe buildup in the reactor core [13]. These variations are accounted for by normalizing the counts in each PGAA measurement to the neutron counts acquired by a proportional 3 He detector located between the curved neutron guide and focusing element [11,13]. The neutron counts from the 3 He detector must also be normalized in each measurement to the HPGe detector real time during the irradiation before being directly compared to background or other comparator element measurements.…”

“…Prompt gamma activation analysis (PGAA) has become a powerful nuclear analytical technique that continues to demonstrate value in an increasing number of applications [1]. The fundamentals, practice, and key advancements in applied methods of PGAA are well documented in the literature [2,3]. With reported detection limits of less than 10 ng g -1 in some materials [4], PGAA is one of the most sensitive, non-destructive analytical techniques available for low-level boron quantification.…”

2.5‐MeV neutron source controlled by high‐intensity pulsed laser generating plasma

“…In the field of neutron reflectometry, for investigating light compounds and biological structures, high neutron fluxes above 10 5 -10 6 n cm −2 s are not required. [9] Prompt γ-ray activation analysis, for example, applied to cultural heritage studies, is less demanding, requiring flux on the sample in the order of 10 3 -10 4 n cm −2 s. [10] Neutron sources for such applications at low fluxes can be realized by using electron Bremsstrahlung by a linear accelerator, RF to generate plasmas coupled to post-ion acceleration, and, more and more, high-intensity pulsed lasers irradiating special targets, a technique which is becoming less and less expensive and handy for many small laboratories. Among such targets, heavy metallic elements, such as Ta, W, and Au, can be used to accelerate a high density of electrons by laser light, converting them in Bremsstrahlung and inducing (γ, n) nuclear reactions with high neutron emission of up to about 10 9 n/s.…”