Neutron spectrometry of (p,n) based neutron fields at the University of Helsinki using the NCT-WES single-moderator directional spectrometer

@misc{myllymaki2026neutron,
  title = {{Neutron spectrometry of (p,n) based neutron fields at the University of Helsinki using the NCT-WES single-moderator directional spectrometer}},
  author = {M. Myllymäki and S. Saariokari and A. Perkkiö and H. Badran and R. Bedogni and E. Brücken and A. I. Castro Campoy and L. Russo and F. L. Frigi and J. M. Gomez-Ros and K. Helariutta and T. Hildén and J. Huikari and J. Lapa and A. Pietropaolo and M. Väänänen and T. Siiskonen},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.39763},
  eprint = {2610.39763},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.39763},
}

TY  - UNPB
TI  - Neutron spectrometry of (p,n) based neutron fields at the University of Helsinki using the NCT-WES single-moderator directional spectrometer
AU  - M. Myllymäki
AU  - S. Saariokari
AU  - A. Perkkiö
AU  - H. Badran
AU  - R. Bedogni
AU  - E. Brücken
AU  - A. I. Castro Campoy
AU  - L. Russo
AU  - F. L. Frigi
AU  - J. M. Gomez-Ros
AU  - K. Helariutta
AU  - T. Hildén
AU  - J. Huikari
AU  - J. Lapa
AU  - A. Pietropaolo
AU  - M. Väänänen
AU  - T. Siiskonen
PY  - 2026
DA  - 2026/10/29
PB  - arXiv
DO  - 10.48550/arxiv.2610.39763
UR  - https://arxiv.org/abs/2610.39763
AB  - A tunable-energy neutron beam produced with up to 1 μA / 10 MeV proton beam on a solid LiF target is available at the Department of Physics of the University of Helsinki for neutron metrology and research applications. This work presents the experimental characterisation of the neutron beams produced at the Helsinki Accelerator Laboratory, and the validation of the \texttt{MCNP6} and \texttt{GEANT4} radiation transport codes for simulating these neutron beams. The neutron spectra produced in the forward direction from 1960, 2040, and 2310 keV protons were measured using the NCT-WES single-moderator directional spectrometer. NCT-WES (Neutron Capture Therapy Wide Energy Spectrometer) is a recently developed single-moderator neutron spectrometer with a sharply directional response, and it is a very convenient instrument to characterise neutron facilities, as it determines the whole spectrum in a single exposure, and has a low sensitivity to room-scattering. The neutron fluence was also determined with the Berthold LB 6411 neutron monitor. The data acquired with NCT-WES were unfolded using the FRUIT unfolding code, starting from guess spectra obtained from \texttt{GEANT4} or \texttt{MCNP6} simulations. The unfolding analysis showed that both transport codes produced plausible spectra, \texttt{MCNP6} being more accurate for the 1960 and 2040 keV irradiations and \texttt{GEANT4} for 2310 keV. The measured values of energy-integrated neutron fluence agree satisfactorily with simulations as well as preliminary measurements with the LB 6411 neutron monitor.
ER  -