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Use of high and low temperature attachment for Weissenberg camera
Author(s) -
Underwood F. A.,
Chapman B. F.
Publication year - 1976
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/s0021889876011205
Subject(s) - materials science , optics , computer science , computer graphics (images) , physics
then it can easily be demonstrated that the instrument wil l not be stable to variations in the intensity of the lamp. Some microdensitometers make use of coloured filters and slits to isolate the regions of interest on a film. On these instruments it is essential to insert f i l ters of the same colour into both beams. The bulb life should be long to avoid the inconvenience of frequent renewals. It should be possible to i l luminate the film from the back to study the features on it by eye. The instrument should be stable to changes in the light of the room in which it is being used. Elect r ica l . There should be good diagnostics for electronic faults and the machine should not be affected by minor variat ions in mains voltage. It should cut out if spikes in the mains voltage occur. Computa t iona l . It should be easy to interface the instrument to a computer. If the instrument is computer controlled, it should have diagnostic test programs to check its performance. Mechan ica l . If a large amount of data is being collected on an instrument connected to a slow output device, such as a paper tape punch, then this punch may become a constraint on the speed of the whole system. It is important to match the type of output peripheral to the anticipated volume of data to be output. It is also worth noting that paper tape punches are l iable to break down quite frequently if they are subject to long heavy cont inuous use. Table movements must be accurate, reliable, and well calibrated in both directions. The moving wedge on a double beam microdensitometer may be connected to the servo motor by a f lexible drive. If this is the case, the drive may stretch with use, or with variat ions in temperature. Opera t iona l . When setting up a densitometer, it is useful to get a display of the results being obtained. On some densitometers this information is output on a printer as an array of numbers, so that it can be related to the orientation of the film.