Measurement of Prompt Fission Neutron Spectrum of Neptunium-237 for 0.62 MeV Incident Neutrons

Than Win, Mamoru Baba, Masanobu Ibaraki, Takako Miura, Toshiya Sanami, Tomohiko Iwasaki, Naohiro Hirakawa

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The prompt fission neutron spectrum of 237Np induced by 0.62 MeV neutrons has been measured by using a Time-of-Flight (TOF) method with a heavily shielded NE213 scintillator. The 4.5 MV Dynamitron accelerator of Tohoku University was used to produce pulsed neutrons. The sample used was NpO2 powder enclosed in a stainless steel container.The fission spectrum data were obtained in the energy range from 0.8 to 12 MeV. Best fit parameters to the experimental data have been derived for the Maxwellian and the Watt type distribution functions. The Maxwellian temperature Tmof the present work was 1.28±0.04 MeV. It is smaller than the Maxwellian temperature of 1.38 MeV given by JENDL-3.2, but is consistent with that derived by the Howerton-Doyas formula on the relation between the average energy or Maxwellian temperature and the average number of prompt fission neutrons. The measured spectrum is well described in terms of the Watt distribution, Xw = Cwsinh exp(–1.01E).

Original languageEnglish
Pages (from-to)486-492
Number of pages7
Journaljournal of nuclear science and technology
Issue number6
Publication statusPublished - 1999 Jan 1


  • Incident energy
  • Maxwellian temperature
  • MeV range 01–10
  • Measurement
  • NE213 scintillator
  • Neptunium 237
  • Prompt fission neutron spectrum
  • Time-of-Flight method
  • Watt distribution

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering


Dive into the research topics of 'Measurement of Prompt Fission Neutron Spectrum of Neptunium-237 for 0.62 MeV Incident Neutrons'. Together they form a unique fingerprint.

Cite this