p-process chaser detector in n - γ coincidences

We propose two types of neutron-γ1−γ2 triple coincidence detectors (not constructed) to chase gamma transitions to produce p-nuclei following the neutron emission in the (γ,n) reaction. Neutrons are detected with 24 3He counters embedded in a polyethylene moderator in Type I detector and with 6 liquid scintillation detectors in Type II detector, respectively. γ rays are detected with two high-purity germanium detectors and four LaBr3(Ce) detectors. The detector which is referred to as p-process chaser detector is used to search for mediating states in 180Ta through which the isomeric and ground states in 180Ta are thermalized in the p-process. A search is made for both resonant states and unresolved states in high nuclear-level-density domain.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

GDR cross sections updated in the IAEA-CRP

The Coordinated Research Project (CRP) with the code F41032 has been launched by the International Atomic Energy Agency (IAEA) in 2016 as a 5-year project with the scientific goal being two-fold: 1) updating the 2000 photonuclear data library and 2) constructing a reference database of photon strength functions. We report the experimental technique and methodology used for the former goal and selected giant-dipole resonance (GDR) data updated in the IAEA-CRP

Photofission and photoneutron cross sections for

A specific objective of the recent IAEA Coordinated Research Project on Photonuclear Data and Photon Strength Functions (Code F41032; Duration 2016-2019) has been to measure photonuclear cross-section data where needed, for unexplored nuclei and cases of discrepant existing data. A dedicated experimental campaign has been conducted at the laser Compton-scattering γ-ray source of the NewSUBARU synchrotron radiation facility of SPring8, Japan, where photoneutron reactions for 11 nuclei from 9Be to 209Bi have been investigated in the Giant Dipole Resonance energy region. The measurements followed the development of a flat-effi ciency moderated neutron detection array and the associated neutron-multiplicity sorting techniques. The IAEA CRP campaign has been followed at NewSUBARU by new measurements of photofission and photoneutron reactions on 238U and 232Th in the energy range of 5.87 MeV – 20.14 MeV. The neutron-multiplicity sorting of high-multiplicity fission neutron coincidence events has been performed using a dedicated energy dependent, multiple firing statistical treatment. The photoneutron (γ, xn) and photofission (γ, fxn) reactions have been discriminated by considering a Gaussian distribution of prompt-fission-neutrons (PFN) multiplicities predicted by the evaporation theory. We here provide preliminary experimental (γ, n), (γ, 2n) and (γ, F) cross sections, average energies of PFN and of photoneutrons emitted in (γ, n) and (γ, 2n) reactions, as well as the mean number of PFN per fission act. The new 238U cross sections are compared with recent statistical-model calculations performed with the EMPIRE code on existing data

γ-Ray Strength Functions and GDR Cross Sections in the IAEA Photonuclear Data Project

We present the latest development of measuring (γ, n) cross sections and giant dipole resonance (GDR) cross sections in the IAEA photonuclear data project. Photoneutron cross sections were measured for 21 isotopes below 2n threshold to construct the γ-ray strength function (γSF) with the γSF method; (γ, n) cross sections are used as experimental constraints on the model E1 and M1 γSFs from the Hartree–Fock–Bogolyubov plus quasi-particle random phase approximation based on the Gogny D1M interaction supplemented with the M1 upbend. GDR cross sections were measured for 11 nuclei from9Be to209Bi by direct neutron-multiplicity sorting with a flat-efficiency neutron detector toward a goal of resolving the long-standing discrepancy between the Livermore and Saclay data. We present γSFs for the Ni isotopic chain and GDR cross sections for159Tb as well as those updated for209Bi.SCOPUS: cp.pinfo:eu-repo/semantics/publishe

Photon-flux determination by the Poisson-fitting technique with quenching corrections

Single- and multi-photon spectra of pulsed -ray beams produced at 17, 34, and 40 MeV in the laser Compton scattering were measured with an 8” 12” NaI(Tl) detector. By using the experimental single-photon spectra as the probability function of generating random numbers, response functions of the NaI(Tl) detector to -fold photons ( = 2, 3, 4 ...) were constructed. The least-square fits to the experimental multi-photon spectra by the Poisson distribution consisting of the response functions were made. The multi-photon spectra measured at 17 and 34 MeV follow the Poisson distribution. A quenching phenomenon of multi-photon spectra was observed for 40 MeV -rays as a result of the saturation at the photomultiplier tube of the NaI(Tl) detector. The original Poisson distributions were restored from the quenched spectra using a saturation curve in the form of with =e. We discuss the accuracy of photon-flux determination

Photoneutron cross-section measurements for 165Ho by the direct neutron-multiplicity sorting at Newsubaru

The Coordinated Research Project of the International Atomic Energy Agency (IAEA CRP-F41032) was launched with a goal to publish two compilations of an updated photonuclear data library and a reference database of photon strength functions. The PHOENIX (PHOto-Excitation and Neutron emIssion cross [X] sections) Collaboration has been established for the IAEA-CRP in the γ-ray beam line GACKO (GAmma Collaboration hutch of KOnan university) of the NewSUBARU synchrotron radiation facility in Japan. The collaboration provides (γ, xn) cross-section data to resolveSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Photoneutron Reaction Data for Nuclear Physics and Astrophysics

We discuss the role of photoneutron reaction data in nuclear physics and astrophysics in conjunction with the Coordinated Research Project of the International Atomic Energy Agency with the code F41032 (IAEA-CRP F41032)

Photoneutron Reaction Data for Nuclear Physics and Astrophysics

info:eu-repo/semantics/publishe