vIMPS is an instrument simulator for the multiplexed Three Axis Spectrometer IN8-IMPS of the ILL. It is part of the vTAS suite (see below) written in Java.

IMPS (Imaging MultiPlexed Spectrometer) is a multi-analyser (6 blades) and multidetector system for the thermal TAS IN8.

Multiplexed instruments make assessing a measurement strategy very difficult without any computer assistance, thus vIMPS was designed to address this problem. It implements a dual real space and reciprocal space graphical interactivity that much facilitates the understanding of the instrument behavior and limits. It makes it possible to easily experiment various measurement strategies through free or predefined instrument configurations. It proved to be a valuable tool for both instrument users and responsible, and also for teaching.

IMPS is still operated in test mode (Jan. 2011) and vIMPS helps experimenting new measurement strategies. These will be implemented as "predefined" once thoroughly tested. Thus the features of the application are a reflection of our current understanding of the capabilities of the instrument.

Ref.: "The vTAS suite: a simulator for classical and multiplexed three-axis neutron spectrometers"
       M. Boehm, A. Filhol, Y. Raoul, J. Kulda, W. Schmidt, K. Schmalzl,
       Nuclear Inst. and Methods in Physics Research, A (2013) 697, 40-44.

The vTAS suite is now a single application vTIU regrouping three TAS simulators:

• vTAS: classical TAS geometry and multiplexed geometry of FLATCONE
• vIMPS: multiplexed geometry of IN8-IMPS
• vUFO: multiplexed geometry of IN12-UFO
  

An early version of vTAS was developped by Alain Bouvet in 1998.
The current vTAS project was funded by the ILL and NMI3.