What to do with a Spectrophotometer? Gilford 250

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What to do with a Spectrophotometer? Gilford 250

Post by abberation » Tue Aug 11, 2015 3:14 am

I need an optical slit for a wire tester (to measure the figure of mirrors).

I have been looking on eBay and surplus stores and I found a Spectrophotometer.

It has an optical slit but I barely know what it does, let alone what is inside.

Before I tear in to it to get the slit out, is there anything I should know?


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Re: What to do with a Spectrophotometer? Gilford 250

Post by Merlin66 » Tue Aug 11, 2015 5:17 am

Basically, an operator wants to know how much light
from a spectrophotometer is absorbed by a sample.
This tells the operator how much of a particular
substance is in the sample. In the 1950’s testing
results were first given as a percentage of the light
transmitted (the amount of light not absorbed by the
sample). This figure then had to be converted (either
manually or electronically) to the actual absorbance
figure - the result the operator actually wanted.
However, this procedure was time-consuming and
there was a good chance for error.
In addition, there was a problem with the electronics.
If most of the light entering a sample is absorbed
by the sample, there is very little light left (that
passes through the sample) that the photometer can
detect and measure. So, part of the job of the electronics
was to increase the strength of the small signal
(generated by the small amount of light) to a point
where it could be used.

The above extract from a Gilford Co. write-up ( http://www.oberlin.edu/archive/holdings ... ilford.pdf ) basically tells me the 1950's spectrophotometer was a monochromator fitted with a photometer at the outlet (rather than a conventional CCD used nowadays)
Somewhere at the input side there will be a narrow slit plate (couldn't find any detail) which could probably be extracted and re-used.
IMHO it would be easier to find a slit plate from Lennox or Thorlabs etc. What slit gap and length are you looking for?
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Re: What to do with a Spectrophotometer? Gilford 250

Post by Wah » Tue Aug 11, 2015 5:41 am

Maybe this slit is suitable for your mirror testing application?
http://adamslab.co.uk/Students%20Lab/Ph ... uct_id=816

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