>>> 'excimer' problem from partlo -- Wed Mar 29 09:30:32 1989 <<<

I filled the laser today and found that the krf tank
was much lower in pressure than it was the last time.
The tank now has only 400 psi of pressure.  The last
time I checked, it had 1200psi.  The Helium tank has
about the same pressure as before.

Could someone look at the plumbing for a possible leak?
There may be no problem, since we are using a smaller
gas cylinder.  I did expect it to last longer than this
though.

>>> 'excimer' problem from evan -- Wed Mar 29 13:37:22 1989 <<<

Problem: low laser gas cylinder pressure

I 'SNOOPED' the CGA fitting and the line up to the manifold valves and
found no sign of a leak.  The reason for lower than expected pressure,
unless it is only due to the cylinder size, is still unexplained.
Perhaps the gas valve was not shut off completely during line purge?

>>> 'excimer' problem from partlo -- Thu May  4 21:03:06 1989 <<<

Changed laser gas
Krf=1700psi
helium=???

Cleaned front and back windows.

1.76 watts with V=155 and R=100 after 1.5 hours.

>>> 'excimer' problem from partlo -- Mon Jun 26 16:30:23 1989 <<<

The helium cylinder is running low could we get another cylinder
ordered, or should I do this?

>>> 'excimer' problem from spence -- Thu Jul 13 14:27:12 1989 <<<

In order to get the laser to lase I put a 3" silicon wafer over the
rear port to act as a mirror. This allowed to laser to work.
However the pulse to pulse uniformity was poor. Using voltages 
above 15000 at a rep rate of 25 gave values of energy per pulse
greater than 255. I will perform some exposures on the
microsteper tomorrow with the unnarrowed excimer to see how much the
resolution is degraded when the bandwidth of the illumination is
greater than the lens is designed for.

>>> 'excimer' problem from evan -- Mon Aug 21 17:10:30 1989 <<<

The precision regulator added to the n2 cylinder is incorrect.  It is self-
relieving and bleeds the house n2.  It will be replaced with a non self-relieving regulator. The back-up cylinder is off line.

>>> 'excimer' problem from evan -- Wed Aug 23 11:45:59 1989 <<<

problem: self-relieving regulator bleeding off house n2.
solution: check valve installed between shut-off and regulator.
the n2 backup system is now working properly.

>>> 'excimer' problem from rnorman -- Tue Sep 12 13:07:58 1989 <<<

Problem: Oil back streaming into the oil trap and saturated it.

Cause: I believe this oil accumulated ever since the pump was
       installed. The users change the gas on a regular basis,
       every two weeks or so, and during this time the mech-pump
       is used to evacuate the excimer before the new gas is 
       installed. After which time the pump is switched off,
       the oil trap is not baked out nor the pump vented to 
       atmosphere to prevent oil back streaming.  The excimer has
       been installed since about 1/88; in view of that, I feel
       we are fortunate that the whole inside of the laser was
       not compleatly covered with oil. The oil trap did a very
       good job in protecting the laser!

Solution: The heater to the oil trap, used for baking out accumulated
          oil, was connected to an AC line which can be easily plugged
          into the wall to bake out the trap; this should be done on a
          regular basis, like every 4 to 6 weeks for 6 to 18 hours. 
          A pressure regulator was installed on the oil trap N2 supply 
          and set to 2 PSI; the N2 vent valve should also be opened
          when the trap is being baked out to drive the oil back into
          the pump.  When the trap is done baking out and the
          mech-pump is to be shut off it should be vented to
          atmosphere; this can be done by opening the trap vent 
          valve for 1-2 minutes or the knob on the oil trap; venting
          with the N2 valve is best, because the trap oil is not pushed
          up into the foreline.  The excimer is up for use.

>>> 'excimer' problem from partlo -- Mon Oct 23 14:51:31 1989 <<<

The n2 cylinder is empty.

>>> 'excimer' problem from evan -- Mon Oct 23 15:52:28 1989 <<<

A new n2 cylinder has been installed. #HP1025    With the new 12-stage house
n2 filter, this cylinder should not empty as fast as the previous one.

>>> 'excimer' problem from partlo -- Fri Nov 17 09:33:42 1989 <<<

the n2 tank for the excimer is empty.

>>> 'excimer' problem from evan -- Fri Nov 17 10:02:55 1989 <<<

A cylinder from dcl with 2100 psi remaining has been installed. #HP368
Cylinder HP1025 was removed.

>>> 'excimer' problem from partlo -- Wed Jan  3 10:56:16 1990 <<<

The N2 tank for purge on the Cymer is empty.

>>> 'excimer' problem from evan -- Wed Jan  3 11:57:32 1990 <<<

A new 3500 psi cylinder of n2 has been installed.

>>> 'excimer' problem from ferguson -- Tue Feb 20 10:33:45 1990 <<<

The nitrogen tank for the laser needs to be changed.

>>> 'excimer' problem from evan -- Tue Feb 20 11:54:33 1990 <<<

A new cylinder of N2 has been installed.

>>> 'excimer' problem from evan -- Fri Feb 23 14:49:49 1990 <<<

A display box that parallels LED indicators with those on the front of the
laser has been installed by the door to GL4.  The status of LASER ON and
STANDBY are indicated.  It has been noticed that the STANDBY lamp stays on
when the LASER ON lights.  This is a 'feature' of the excimer design and is
normal.

>>> 'excimer' problem from evan -- Thu Mar  1 16:29:30 1990 <<<

There is a lasergas cylinder which appeared in the gas storage area.
Is this a new cylinder for your laser or is this an empty?  There are
no UC storehouse tag on this.

>>> 'excimer' problem from richard -- Thu Mar  8 16:59:32 1990 <<<

N2 on the excimer is below 100psi

>>> 'excimer' problem from evan -- Fri Mar  9 09:39:53 1990 <<<

replaced n2 cylinder. excimer is up
>>> 'excimer' problem from callicot -- Mon Mar 19 13:44:12 1990 <<< [No Comment]

>>> 'excimer' problem from callicot -- Mon Mar 19 20:45:11 1990 <<<

Nitrogen Out!

>>> 'excimer' problem from richard -- Tue Mar 20 09:23:56 1990 <<<

N2 bottle is out.

>>> 'excimer' problem from evan -- Tue Mar 20 14:11:50 1990 <<<

A new cylinder of n2 was installed.  All fittings from cylinder to house n2
check valve were leak checked; no leaks found.  I found the regulators had been
altered; the intermediate regulator had been screwed all the way IN.  These
regulators are not to be changed by anyone but lab staff.  If the n2 cylinder
is low, screwing in the valve will not get you more pressure.  The setting of
the precision regulator is very critical. It has been set to deliver 66 psi
to the laser, as read by the control box, when house n2 falls.  By setting this
higher, too much cylinder n2 is used.  
Please report if the laser cuts out on low n2 error but do not touch regulators.

>>> 'excimer' problem from callicot -- Thu Apr 19 16:45:20 1990 <<<

New gas fill
shot count 281.7M

KrF Pres. 120 psi
N2 Pres. 110 psi

>>> 'excimer' problem from callicot -- Mon Apr 23 21:53:09 1990 <<<


New gas fill
Kr pressure 120 psi
N2 pressure 85 psi
Shots 282.9M
------ N2 is almost out !!! ------
------ Low shot power???    ------

>>> 'excimer' fix from evan -- Tue May  1 16:53:54 1990 <<<

New n2 cylinder, #688, installed.  The cylinder cap and outlet plug were
gone from the chase.  Did one of you move it somewhere?
