The signal of sample environment as a way to measure sample transmission

In a recent article, the combined effects of the sample environment and instrument collimation have been described for the dedicated instrument for amorphous systems at ILL (D4) [1]. This undesirable effects on the diffractograms force to make complex and careful absorption corrections, which not always produce good enough results. In such cases, parts of the detector banks must be discarded with the consequent lose of statistics. This experimental problem can be used to obtain the transmission of the sample by an indirect way. Considering the most generalized case of a cylindrical sample with a cylindrical sample environment (furnace, cryostat, etc), the diffractogram can be described as coming from three different sources: the sample itself, the upstream and downstream sample environment. These sources produce three well-differenced regions on the individual diffractograms observed by one particular detector. These three different measured signals are linear combination of the sample, upstream and downstream intensities produced by each source. In this way, upstream and downstream intensities can be determined, and the experimental transmission of the sample can be obtained. The experimental results corresponding to the standard cryostat are compared with the theoretical calculation of the transmission for a series of samples measured at D4 over the past years. This comparison shows that an undesirable effect observed on the diffractograms could even be useful under some circumstances