The equipment to form the polarized neutron beam
for fundamental investigations
at channel 51 of SINQ PSI (Switzerland)
The equipment for a polarized cold
neutron beam of
sector 50 at SINQ was created by common efforts of Petersburg Nuclear
Physics Institute (Gatchina, Russia) and Paul Scherrer Institute
(Villigen, Switzerland). The equipment is intended for formation
of a polarized cold neutron beam for joint fundamental studies in the
field of nuclear physics.
The equipment was worked out with due regard for the restricted area for
installation of the polarizer and the filter of gamma-quanta and fast
neutrons. The system of polarization and filtration includes
polarizer , multichannel mirror
bender and mirror
These three mirror units for the beam formation serve as a deflector which
deviates the beam of cold neutrons out of the direct view of the cold
neutron source and provides filtration of the cold neutron beam from
gamma-quanta and fast neutrons. The equipment includes also an analyzer
of the beam polarization.
The Design is based on the experience of PNPI in production of polarized cold
neutron beams of high flux density and multichannel neutron guides on the
basis of polarizing CoFe/TiZr and
non-magnetic NiMo/Ti supermirrors with m=2
(by definition, the effective critical reflection angle of a supermirror
in m times exceeds that of Ni). The experience of PNPI in production of
analyzers has been put to good use, too. The Design is based also on the
experience of PSI in development of Ni/Ti supermirrors with m=2 and m=3.5.
The main parameters of the Tract Units are represented in a
The main geometrical parameters of the polarizer with a condenser
|Element||beam cross-section (mm2)||length (mm)||channel width (mm)
||deflected angle (rad)
||number of channels||glass thickness (mm)||vertical wall coating ||horizontal wall coating
||1||5.0||Ni/Ti (m=3)||NiMo/Ti (m=2)
The general view of the
The view of the multichannel
polarizer from the side of the
Calculated and measured spectral distributions of
the neutron flux density.
Calculated and measured spectral dependence of
the neutron beam polarization.
The top and side views of the equipment for forming the polarized cold neutron beam at SINQ:
- the neutron guide with the supermirrors Ni/Ti;
- the shutter;
- the polarizing bender with supermirrors CoFe/TiN and FeCo/TiZr;
- the 6 Li-doped plastic shutter;
- the condenser with non-magnetic supermirrors NiMo/Ti;
- the radiofrequency spin flipper;
- the moveable truss;
- the beam;
- the external shielding.
The cross sections of the polarizing bender (A-A), the condenser (B-B) and
the spin flipper (C-C):
CoFe/TiN and FeCo/TiZr supermirrors (1), the iron
spacers (2), the titanium stencils (3), the stainless steel vacuum jacket (4),
the magnetic vacuum system with ferrite elements (5), the blocks of the
stainless steel shielding (6), the optical section (7), the boron
plastic (8), the iron vacuum jacket-magnetic conductor (9),
the radiofrequency coils (10), the magnetic system of the spin flipper(11).
Contact person: Prof. Ralph Eichler,
Head of Particles and Matter Dept.
CH -- 5232 Villigen PSI, Switzerland
Phone: + (41) 563103216