Determination of the number of pulsed laser-Compton scattering photons

Photoneutron cross sections for neodymium isotopes: Toward a unified understanding of(γ,n)and(n,γ)reactions in the rare earth region

“…[22] after detecting the beam with a 6 × 5 NaI(Tl) detector mounted at the end of the beamline. Typically 20% corrections were made for the transmission rate of the LCS γ rays through the NaI(Tl) detector.…”

“…These reactions could be responsible for a large production of neutrons during the 147 Nd(n, ) 148 Nd 10 given burning phases, namely, the core He-burning of massive stars (heavier than 10M ) and the shell He-burning during the thermal AGB instabilities (thermal pulses) of low-and intermediate-mass stars (<10M ) [1,58]. The core He-burning of solar-metallicity stars has proved its ability to produce the lightest s elements (i.e., 70 A 90), but since 22 Ne is a secondary source, the efficiency remains identical for metal-poor stars. The astrophysical models underlying the thermal pulse scenario (believed to be responsible for the production of the A > 90 s elements) remain quite uncertain in many respects, in particular in the description of the mixing mechanisms that could be at the origin of the neutron production.…”

Photoneutron cross section measurements on Sm isotopes

“…NewSUBARU provides a ∼10 5 photons per second in 3 − 5% bandwidth γ-ray beam. The γ-ray beam flux was monitored with a 6"×5" NaI(Tl) detector and the number of incident γ photons was obtained using the "pile-up method" described in [8]. The samarium samples were mounted at the center of a 4π neutron detector comprised of 20 3 He proportional counters placed in three concentric rings embedded in a polyethylene moderator.…”

Photoneutron cross sections for samarium isotopes: Toward a unified understanding of(γ,n)and(n,γ)reactions in the rare earth region

“…Thus, the LCS γ rays are generated in bunches corresponding to each laser light pulse. The number of LCS γ rays per bunch is given by a Poisson distribution [21] with a mean which depends on the laser and electron beam intensity, collimator aperture, and the probability of interaction between the laser photons and the relativistic electrons.…”

“…The number of recorded γ photons was obtained by using the "pile-up method" described in [21], which is based on the Poisson fitting method originally developed at the Electrotechnical Laboratory [22,23]. The uncertainty of the Poisson fitting method is estimated to be 3%, which is attributed to the fitting and the energy linearity of the γ -ray detector in its response to multiphotons.…”