Advances in detectors for single crystal neutron diffraction

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 554; no. 1; pp. 392 - 405
• Main Authors: Buffet, J.C., Clergeau, J.F., Cooper, R.G., Darpentigny, J., De Laulany, A., Fermon, C., Fetal, S., Fraga, F., Guérard, B., Kampmann, R., Kastenmueller, A., Mc Intyre, G.J., Manzin, G., Meilleur, F., Millier, F., Rhodes, N., Rosta, L., Schooneveld, E., Smith, G.C., Takahashi, H., Van Esch, P., Van Vuure, T.L., Zeitelhack, K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2005
• Subjects: Drift chamber; MSGC; Neutron diffraction; Scintillation; 29.40.Mc; Neutron diffraction; MSGC; Scintillation; 29.40.Cs; 61.12.Ld; Drift chamber; 29.40.Gx
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2005.08.018

Parallax error severely limits the use of gas detectors for neutron and X-ray single-crystal diffractometry. This is particularly the case in Neutron Macromolecule Crystallography (NMC), where a large solid angle is needed. High-resolution cylindrical detectors based on Neutron Image Plates provide a large angular coverage but they are gamma sensitive and do not allow time-resolved measurements. We describe the principle of a gas counter, the multi-blade Microstrip Gas Chamber (MSGC), which has the potential to design parallax-free cylindrical detectors. It contains radial MSGC plates, providing a partitioning of the gas volume and a segmentation of the signal readout. The axial coordinate is measured by reading out the charge signal on the anodes and the trans-axial coordinate is deduced from the electron drift distance measured optically using the time difference between the primary and the avalanche light. Expected characteristics are a sub-millimeter position resolution, a sub-microsecond time resolution, and a global counting rate greater than 10 7 s - 1 .