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Characteristics

Multianalyser
crystals 9 independent turnable blades40 x 120 mm2 eachplastically bent Ge111 (R = 5m)
Acceptance angle ~ 9°
Gain in counting rate a factor 3
mechanism completely amagneticno mechanism on the beamdeveloped by TEKNIKER
Variable collimator system
blades Borated Al1mm thickness
size 120 mm height200 mm long
Definition of the outgoing beamPrevents cross-talk between channelsControlled by software
Position sensitive Detector
He filled tubes 54 tubes of Φ = 9 mm1 mm spacing
size 539 x 200 mm2
Horizontal spatial resolution 5 mm
High efficiency for thermal neutronsHigh count-rate linearity for weak signalsVery low noiseSimultaneous backgroundVariable analyser-detector distance
Protection
material borated polyethylene200mm-thickness
additional protectiondsample-analyzer normal one = 400-700mmextended = 700-1100mm
keep the conventional TAS configurationanalyzer and the detector inside the same protectionsame movements as a TAS

The IMPS assembly comprises a multi-analyser made of 9 independent crystals, a computer controlled variable collimator and a position sensitive detector. It makes it possible of measuring in focused or imaging modes.

Its main characteristics are:

  • possibility on working focused or imaging
  • no mechanism on the beam
  • mechanics completely amagnetic 

IMPS being capable of focused, imaging or even mixed mode measuring geometries, its use would be quite complicated without a computer assistance. Thus the software vIMPS was developed which offers both a simulation and a display mode:

  • simulation mode: one can modify all instrument parameters and then play with the measurement parameters by interactively moving either the Q,ki,kf triangles relativeto each analyser blade (reciprocal space) or the instrument parts (direct space).
  • display mode: plot the spectrum, the Q,ki,kf triangles and the instrument configuration corresponding to a given data file.

The IMPS project was developed in collaboration with Spanish scientific partners, i.e. Ministerio de Educación y Ciencia (MEC).

First installation on IN8C, December 2006
First sample, June 2007