Laser longevity (summary of replies)

From: DR LLOYD (D.R.LLOYD@bham.ac.uk)
Date: Wed May 30 2001 - 12:35:14 EST


Dear colleagues

Thanks to the six respondents to my question about the longevity
of the Cyonics 2201 laser fitted to our Coulter Elite. We will follow
up your suggestions. For those who are interested please find
below, as promised, though a little late, a summary of the replies.

One respondent thought that our 2048 hours over 2.5 years was
good compared with his 1500 hours. The remaining 5 respondents,
speaking on behalf of 10 instruments thought that we should get
much better; up to 7 years or 10,000 hours (same laser on a BD
instrument).

Suggestions for improving laser longevity essentially all revolved
around improving cooling, and included;
Clean filters regularly (we do).
Turn laser down/off when instrument is not acquiring data.
Turn laser off/down before turning the instrument (and cooling fans)
off.

The actual replies are given below.

Cyonics model 2201 usually lasts between five and ten thousand
hours on the FACS can/sort/calibur. Ortho Cytorons got half that
life span due to inadequate cooling.  This laser has a rated output
of 40+mW, so running it at 15mW should give a long life if you
provide adequate cooling. Also, (if you do not already) turn the
laser to standby for about five minutes prior to turning your
instrument off to let the laser cool down.


In my experience, you have done rather well.  I had an air cooled
laser that lasted barely 1500 hours (at 60 MW), it was run with a
fan in a room with the air conditioning set at 18C. Most suppliers I
have talked to do not expect to get more than 1500 hrs from an air
cooled laser. We have an air cooled system which maybe slightly
different if yours is water cooled. We have the fan system on a
separate switch. This laser HeCd has been running at 25-50mW for
thousands of hours without a problem.
A similar laser came in with our second hand Coulter that
had no additional cooling after shut down and had gone down
in half the running hours. We always have our laser cooling for at
least 15 minutes. I certainly wouldn't turn off the fans any earlier
than 10 mins. If you can adapt you electric's it could be well worth
doing. It certainly won't harm your laser life.

We have our Cyonics laser running since 1995 without any
problem...yet.The Elite is installed in a room with air conditioning
and a tolerance of plus or minus 1 °C. This as been done mostly,
because of the sorting performance for which it is knowned to be
influenced by the room temperature viscosity of the sheath, drop
delay etc.M.G.Ormerod book Flow Cytometry). We also evacuated
the laser heat with the cooling cube oriented through a ventilation
duct which exhaust used air out of the building. We certainly have
passed by far your 2048 hours of use.To my knowledge all my
colleagues (5)operating the Elite for about the same amount of time
in this area nobody had replaced the laser ..yet.

The Cyonics LASER on our Coulter Elite has lasted a fairly long
time.  We are on our second LASER, and we purchased our Elite
in December of 1990.  The only tip I have is to make sure that the
air filters on the air system of the LASER is clean.  When our first
LASER failed in June 1996, my repair man urged me to make sure
that I changed and/or cleaned the air filter.  In my case, it is a
nylon stocking (which reminds me, I need to check it soon.  So,
we've had good longevity, the last room my Elite was in had high
humidity, and the air conditioning was not very good (high humidity
and about 10 degree shifts in temperature whenever the A/C came
on/off during the day.  Anyway, I hope that helps

Regarding tube life of CYONICS lasers, a FACScan I bought in
2/94 (located in CH) is still running more than 7 years later. The lab
is air conditioned, kept very cool and the FACScan is next to the
air conditioning vent. The hot air from the laser is directed back into
the air conditioning unit, so cool air is constantly pulled through the
cytometer and laser.
In my current lab in the USA, the CYONICS laser is directly vented
to the room ventilation system. This FACScan was manufactured
in 1994 as well. I had a heat dissipation chimney with ventilation
fan mounted to the back of the FACScan. When the power to the
FACScan is turned on, the auxiliary cooling fan is turned on to
draw additional air through the laser to have it run cooler and cool
down faster when the instrument is turned off. Based on n=2, I'll
conclude that keeping the ambient temperature and the laser
cooler prolongs its life.
When the instrument will not be used for more than 30-45 minutes,
I have my users turn it off. I also try to schedule users so that
sample acquisition can be "piggy-backed", running one after the
other to lessen the likelihood of the instrument being switched
ON/OFF more than a few times during the course of the day. Some
people feel the instrument should be left on over the course of the
entire day to prolong tube life, but with turning it off several times in
a day and having both tubes still running after 7 years, it doesn't
seem to support that school of thought any more than turning it
off when not be used for more than 30 minutes.

Sincere thanks again to those who took the time to reply






David R Lloyd MMedSc CBiol MIBiol
Research Associate
School of Chemical Engineering
University of Birmingham
Edgbaston
Birmingham B15 2TT
England

t; +44 (0)121 414 5357
e; D.R.Lloyd@bham.ac.uk
http://www.bham.ac.uk/ChemEng/actg/hbhome.htm



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