9 independent turnable blades
40 x 120 mm2 each
plastically bent Ge111 (R = 5m)

Acceptance angle

~ 9°

Gain in counting rate

a factor 3


completely amagnetic
no mechanism on the beam
developed by TEKNIKER

Variable collimator system


Borated Al
1mm thickness


120 mm height
200 mm long

Definition of the outgoing beam
Prevents cross-talk between channels
Controlled by software

Position sensitive Detector

He filled tubes

54 tubes of Φ = 9 mm
1 mm spacing


539 x 200 mm2

Horizontal spatial resolution

5 mm

High efficiency for thermal neutrons
High count-rate linearity for weak signals
Very low noise
Simultaneous background
Variable analyser-detector distance



borated polyethylene

additional protection

normal one = 400-700mm
extended = 700-1100mm

keep the conventional TAS configuration
analyzer and the detector inside the same protection
same 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