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BL05 NOP Neutron Optics and Fundamental Physics (NOP)


Particle physics and cosmology with low energy neutrons

Research ObjectivesSearch for rare phenomena beyond the standard model of particle physics. Precision measurements on the decay, scattering, and interference of low energy neutrons, R&D of neutron optics for precise and efficient neutron measurements.
FeaturesHigh-intensity low-energy neutrons in a low background environment. The upstream supermirror bender provides the three unique neutron beams, low-divergence, unpolarized, and polarized beams.


Last Update: 2015-04-24

InstrumentNeutron Optics and Fundamental Physics (NOP)
Overview of instrumentThe NOP beamline provides three unique neutron beams, a low-divergence beam, an unpolarized beam, and a polarized beam, by splitting one beamline with supermirror benders.
ModeratorCoupled hydrogen moderator
Neutron wavelength2Å~9Å
Beam profile
(16 m position, height × width)
Low-divergence beam branch : 80 mm × 20 mm
Unpolarized beam branch : 55 mm × 45 mm
Polarized beam branch : 80 mm × 50 mm
Neutron intensity
(16 m position, @ 1 MW)
Low-divergence beam branch : 5.4×104 n/s/cm2
Unpolarized beam branch : 9.4×107 n/s/cm2
Polarized beam branch : 3.9×107 n/s/cm2
Beam divergence
(16 m position)
Low-divergence beam branch : 5.4×10-2 µstr
Unpolarized beam branch : 1.0×102 µstr
Polarized beam branch : 1.9×102 µstr
Average neutron polarizationPolarized beam branch : 96%
Auxiliary equipmentB4C slits at the 7.5 m and 12 m positions on the low-divergence beam branch.
B4C slits at the 12 m position on the unpolarized and polarized beam branches.
A Doppler shifter for UNC production.
OtherProper radiation shielding is required for experimental setups that emit gamma rays or scatter neutrons, as the walls and ceiling of the NOP beamline are not shielded.

Beamline Team

ContactKenji MISHIMA (Institute of Materials Structure Science/J-PARC Center, KEK)
Secondary contactTakashi INO (Institute of Materials Structure Science/J-PARC Center, KEK)
Kaoru TAKETANI (Institute of Materials Structure Science/J-PARC Center, KEK)

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