In conjunction with an industrial partner (Sasol), the applicants have previously used INS measurements performed on the MAPS spectrometer to characterise a series of iron based Fischer-Tropsch synthesis catalysts after various regimes of reaction testing. Most recently (RB1610413), the programme of work has been extended to examine the highly lucrative Fischer-Tropsch-to-olefins process that requires the addition of specific chemical promoters to shift the product distribution from high molecular weight linear alkanes to low molecular weight olefins. This proposal seeks to use INS to determine how a particular combination of chemical modifiers can affect the evolutionary phase of the catalyst conditioning process.This proposal is a re-submission (RB1620205); the original beamtime was cancelled due to spectrometer flux problems that seriously compromised spectral acquisition.