Neutron capture cross sections of curium isotopes measured with ANNRI at J-PARC

ABSTRACT

The neutron capture cross sections of ${ }^{244}\mathrm{C}\mathrm{m}$ and ${ }^{246}\mathrm{C}\mathrm{m}$ were measured for the neutron energy range of 1–1000 eV via the neutron time-of-flight method with Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI) at Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). The world’s most intense neutron pulses from the Japan Spallation Neutron Source (JSNS) enable the accurate measurement of neutron capture cross sections. Besides, single-bunched neutron pulses allow the analysis in a higher neutron energy region than the previous measurement at ANNRI. The resonance analyses were performed up to 1000 eV by using a resonance shape analysis code REFIT. The spectra of prompt gamma-rays from neutron capture reactions of ${ }^{244}\mathrm{C}\mathrm{m}$ and ${ }^{246}\mathrm{C}\mathrm{m}$ were also obtained, and 43 and 10 prompt gamma-ray peaks from ${ }^{244}\mathrm{C}\mathrm{m}$ ($n,\gamma$) and ${ }^{246}\mathrm{C}\mathrm{m}$ ($n,\gamma$) reactions were newly observed, respectively.

KEYWORDS:

• ²⁴⁴Cm
• ²⁴⁶Cm
• neutron capture cross section
• J-PARC
• MLF
• ANNRI
• minor actinide
• neutron time-of-flight method
• resonance
• measurement

Acknowledgments

The authors are grateful to the accelerator and technical staff at J-PARC for the operation of accelerator facilities and other experimental supports. The neutron experiment at the Materials and Life Science Experimental Facility of the J-PARC was performed under the user program [Proposal No. 2018P0100].

Disclosure statement

No potential conflict of interest was reported by the authors.