PA20 (G5-1)
G5-1
CASEMATE SHIELD
Rectangular slits
VACUUM TANK
Sample
space
COLLIMATOR
a t tenuator
M o nochromator
(velocity selector)
guide
beam
3 He
2D detector
128x128 pixels
nose
Beam stop
Spin flip
Removable guides
lenses
L c (max) = 15.5 m
D0 = 1 m – 19 m
PA20 is a brand new small angle neutron s ca ttering i nstrument designed for
SANS/GISANS experi ments requi ring a good resoluti on and/or flux. It is
equipped wi th a optional pola rized beam and diaphra gms i n the collima tor
adapted for GISANS measurements as well . PA20 is ins talled a t the end of the
cold neutron guide G5 and was deli vered and commissioned in 2015. The
wa velength of the incoming neutrons are produced from a whi te bea m by a
mechani cal veloci ty selector ; wa velength ma y va ry from 0.35 nm up to 2 nm.
The neutrons a re then collima ted by a series diaphragms and sections of
moveable guides in an eva cuated collima tor of total length 16m. In non
polari zed mode, the double-V polari zer ins talled after the selector can be put
aside thus reaching 18.5m of collima tion in total . Si x diaphragms along the
collima tor ca n be defined by the user a ccording to i ts requi rements (flux,
resolution, beam size) as well as focusing lenses and an extensible nose at the
end of the collima tor. The sample holder is equipped wi th a double goniometer,
hei ght and translation motions of a rota ting table tha t can hos t hea vy
equipment like furna ces , electromagnets (1.5T) and cryomagnets (up to 10T),
linea r tempera ture-controlled sample changers and shea ring cell (Couette cell
or Cone and Pla te). The 3He mul ti-detector, wi th 128 x 128 cells of 5 x 5 mm2,
can be positioned a t any dis tance between 1.2m and 19m from the sample i n
the l ongitudinal di rection in i ts va cuum tube. While the va cuum tube cannot be
moved, the 3He detector can be moved laterall y to increase the a vailable Qra nge.
Contact for experiments : Grégory Cha boussant ([email protected])
Syl va i n Désert ([email protected])
polarizer
L NP = 3.0 m
Type of instrument
Small angle neutron scattering for high resolution, large
dynamical Q range and polarized neutrons
Beam tube
Neutron guide G51(cold source), super-mirror coating
Monochromator
Mechanical selector 3.5 Å <  < 20 Å with /=0.12
Max flux at sample
Max beam size at sample
strongly dependent on the chosen collimation
typical size 1x1 cm2 but up to 2.5x2.5 cm2 if necessary
Moment transfer range
Distance sample detector
Collimation
10-4 Å -1 < Q < 1.0 Å -1
1.2 m to 19 m
Rectangular and adjustable slits. Collimation lengths
are 1.25 m, 3 m, 4.25m, 8 m, 11.75m, 15.5m, 18.5m (in
polarized mode only). Focusing lenses and extensible nose.
Choice between 16 attenuators of different transmissions.
3He XY multidetector 64x64 cm2, 5x5mm pixel size
Attenuators
Detector
Ancillary equipment
Automatic sample changer with temperature control
Furnace (50-300 Celsius)
Cryomagnets (1.5K, horizontal field 10T)
Electromagnets with automated sample changer (1.5T)
Couette type viscosimeter