TOF-elastic resolution spectroscopy: time domain analysis of weakly scattering (biological) samples

Elastic resolution spectroscopy (ERS), a new application of the time-of-flight method, addresses the problem of weak scattering signals. Since only the maximum of the spectrum at zero energy transfer needs to be determined with sufficient statistical accuracy, significantly smaller samples, as compared to conventional spectroscopy, can be studied. The peak intensity is recorded versus the reciprocal width of the instrumental resolution function by adjusting the speed of the chopper system. This approach yields a close approximation to the intermediate scattering function in the time domain. A neutron ERS analysis of molecular motions in alanine-dipeptide crystals and hydrated myoglobin is presented. 2003 Elsevier Science B.V. All rights reserved.