When the TS1 project was started it was essential to know what the output was of the current moderators and that the simulations could correctly model this. To this end the calibration rig was constructed as shown in the figure. The rig sits in a standard tomkinson flange and so can be used on most ISIS beamlines. There is a calibrated monitor which sits at the centre of the beam at the sample position and gives the absolute flux. The beam then bragg scatters from a ceria powder sample to backscattering detectors to give a 'high' resolution diffraction pattern. Each diffraction peak in the is dominated by the moderator structure for that particular wavelength and therefore the backscattered diffraction pattern gives essentail info about the moderator time structure. The measurements for most ISIS instruments are available to download.