Calculations of neutron spectra after neutron-neutron scattering

Journal Article (Journal Article)

A direct neutron-neutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the proton-proton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum - Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

Full Text

Duke Authors

Cited Authors

  • Crawford, BE; Stephenson, SL; Howell, CR; Mitchell, GE; Tornow, W; Furman, WI; Lychagin, EV; Muzichka, AY; Nekhaev, GV; Strelkov, AV; Sharapov, EI; Shvetsov, VN

Published Date

  • September 1, 2004

Published In

Volume / Issue

  • 30 / 9

Start / End Page

  • 1269 - 1285

International Standard Serial Number (ISSN)

  • 0954-3899

Digital Object Identifier (DOI)

  • 10.1088/0954-3899/30/9/024

Citation Source

  • Scopus