Premium
A small‐angle X‐ray camera using a two‐dimensional multiwire proportional chamber
Author(s) -
Furuno T.,
Sasabe H.,
Ikegami A.
Publication year - 1987
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s002188988708720x
Subject(s) - optics , physics , detector , anode , diffraction , microchannel plate detector , wire chamber , materials science , viewing angle , electrode , liquid crystal display , quantum mechanics
The construction and performance of a small‐angle X‐ray camera equipped with a two‐dimensional multiwire proportional chamber (two‐dimensional MWPC) are described. The system has been used for studies of the structure of biological samples with a conventional rotating‐anode X‐ray source. The small‐angle camera is of Franks type with two orthogonal platinum‐coated bent optical flats placed in a helium‐tight box. The specimen‐to‐detector distance is variable between 60 and 260 cm. The sensitive area of the two‐dimensional MWPC is 256 × 256 mm with 256 × 256 resolution elements. The camera covers high angles up to about 5 Å, although diffraction line widths in this region are highly broadened owing to parallax. The electronic system comprises NIM modules, a hand‐made module and a commercially available compact two‐dimensional multichannel analyser (two‐dimensional MCA). The two‐dimensional MCA has a memory size of 256 × 256 channels (24 bits/channel). The estimated dead time of this system is approximately 5 μs, which permits a maximum count rate of 20 kHz at 10% loss. Diffraction patterns of a Langmuir–Blodgett film of arachidic acid and stacked purple membranes and a solution scattering of horse spleen apoferritin are demonstrated as examples.