Inexpensive replacement for a He/Ne 20 mW laser?

[mathog]

We have an old phosphorimager that contains a Uniphase 1135P laser which
is no longer operational. Near as I can tell the rest of that scanner
is working properly. The 1135P is 632.8nm laser, 20mW. They still sell
lasers like that but they are $$$, and the lab that owns the instrument
doesn't want to spend much to fix it. I think for this application the
key requirement is that the replacement laser's output be stable (<5%
certainly, %1< if possible), and secondarily, that the wavelength be as
close to the original as possible.

Any suggestions for a solid state laser that would be an acceptable
replacement? My guess is that the scanner might work with even a run
of the mill red laser pointer bolted in, but that the power output
variations would result in a mottled image.

Thanks

David Mathog

 

[Samuel M. Goldwasser]

mathog <dmathog@gmail.com> writes:

We have an old phosphorimager that contains a Uniphase 1135P laser
which is no longer operational. Near as I can tell the rest of that
scanner is working properly. The 1135P is 632.8nm laser, 20mW. They
still sell lasers like that but they are $$$, and the lab that owns
the instrument doesn't want to spend much to fix it. I think for this
application the key requirement is that the replacement laser's output
be stable (<5% certainly, %1< if possible), and secondarily, that the
wavelength be as close to the original as possible.

Any suggestions for a solid state laser that would be an acceptable
replacement? My guess is that the scanner might work with even a run
of the mill red laser pointer bolted in, but that the power output
variations would result in a mottled image.

How much are they willing to pay? 1135Ps are available surplus in
excellent working condition for a small fraction of the new price.

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[mathog]

Samuel M. Goldwasser wrote:

1135Ps are available surplus in
excellent working condition for a small fraction of the new price.

Where? The ones I have seen on ebay are pretty iffy - no estimate on
remaining life, usually they don't even say if the tube is known to
work. Plus I don't know if it is the tube or the power supply blown.

Is there a simple way to test the power supply at the leads that go into
the tube? The power supply is out of reach in a part of the instrument
case that I could not disassemble. (There is no instrument service
manual.) None of the voltmeters at my disposal can handle kV
measurements, at least not directly.

Thanks.

 

[whit3rd]

On Tuesday, January 17, 2012 4:30:39 PM UTC-8, mathog wrote:

Samuel M. Goldwasser wrote:

1135Ps are available surplus in
excellent working condition for a small fraction of the new price.

Where? The ones I have seen on ebay are pretty iffy

I think you're right to be skeptical of used items, in this case.
The gas laser, a HeNe type, depends on the correct gas
mixture, and the helium will, with time, diffuse out of the envelope.

Buy a new part, if you can.

In related news, all the common CF fluorescent globe-bulb
replacements use a small bit of radioactive material to get 'em
started: don't stockpile those lamps, because the half-life of
that item is only a decade or so. For infrequently used lights
(attic, crawlspace, guestroom closets) you'll get better service
from incandescents.