Date: Thu, 07 Dec 1995 08:56:51 -0800
Subject: penning problem fixed
From: Michael Shaffer

Cc: johnf@geology.wisc.edu, summer@probe.geol.sc.edu,

Shervais@epoch.geol.sc.edu, pierce@magic.geol.ucsb.edu,

patrick@magic.geol.ucsb.edu, microprobe@tamu.edu,

WML5079@geopsun.tamu.edu, vicenzi@princeton.edu, rnielsen@oce.orst.edu,

garcia@soest.hawaii.edu, hulse@elepaio.soest.hawaii.edu,

jinnys@geophysics.rice.edu, miltonp@ruf.rice.edu, Corvos@aol.com,

jstor@owlnet.rice.edu, drake@sx50.lpl.arizona.edu,

chrisc@sx50.lpl.arizona.edu, teska@sx50.lpl.arizona.edu,

raudsepp@unixg.ubc.ca, schiffman@jade.ucdavis.edu,

roeske@jade.ucdavis.edu, steele@geo1.uchicago.edu, Jbarjr@aol.com,

jcr@quartz.geology.utoronto.ca, wpnash@mines.utah.edu,

rlambert@mines.utah.edu, noso@vtvm1.cc.vt.edu,

gmorgan@GEOADM.GCN.uoknor.edu, k56@psuvm.psu.edu,

GASP@GUARANY.CPD.UNB.BR, MARCOS@IF1.UFRGS.BR,

d_martinez@rumac.upr.clu.edu, rmason@kean.ucs.mun.ca,

basu@ucs.indiana.edu, doraism@ucs.indiana.edu, brophy@ucs.indiana.edu,

wintsch@ucs.indiana.edu, mbarton@magnus.acs.ohio-state.edu,

mcomerfo@magnus.acs.ohio-state.edu, chrmille@magnus.acs.ohio-state.edu,

fnkps@aurora.alaska.edu, valley@ice.geology.wisc.edu,

johnf@ice.geology.wisc.edu, cjwood@dow.com, mlw@probe.geo.umass.edu,

B.Robinson@DEM.CSIRO.Au, jstirlin@emr.ca, F.Scott@unsw.edu.au,

croudin@UCSD.EDU, jeronimo@pppg.ufba.br, rjs@almaden.ibm.com,

snow@lanl.gov, gmckay@snmail.jsc.nasa.gov,

wagstaff@snmail.jsc.nasa.gov, npearson@laurel.ocs.mq.edu.au,

huw@cemmsa.adelaide.edu.au, CF_Minerals@cyberstore.ca,

claudio@quartz.geology.utoronto.ca, bo.johanson@gsf.fi,

Kari.Kojonen@gsf.fi, WAUTIER@GEM.UCL.AC.BE, maggy@sparky2.esd.mun.ca,

essene@umich.edu, jdonovan@garnet.berkeley.edu,

pking@sparky2.esd.mun.ca, edoehne@Getty.edu, mdl@probe.geo.umass.edu,

nick@geo.utep.edu, rjchapman@bldgwall.lan1.umanitoba.ca,

beamm@bukula.enternet.com.au, cameca@world-net.sct.fr,

CamecaFlo@aol.com, CamecaSam@aol.com

Message-id: <2.2b8.32.19951207165651.0069e42c@oregon.uoregon.edu>

MIME-version: 1.0

X-Mailer: Windows Eudora Pro Version 2.2b8 (32)

Content-type: text/plain; charset="us-ascii"

Content-transfer-encoding: 7BIT

Status: OR



Hi Ed, (cc'd to all users)



Thanx for calling, and sorry I missed your call. I was in early this

morning for this problem, but 6AM????????



Anyway, the problem you talk about (I think) is the Penning gauge refusing

to "fire" which at times can be caused by "too good" of a vacuum, which

explains your coincidence with LN2. It happens to me all the time. I

wouldn't be too fearful of banging on it ... just don't use a sledge hammer.

I tap the sensor with the metal end of a long small screwdriver because I

think metallic sonic vibs due the trick.

^My^ problem was the vacuum logic never switching to the Penning gauge ...

it would just sit there at 1E-1 for hours. As many users pointed out I had a

leaky detector window ... I replaced it this morning and the Cameca it alive

and ready for albitized feldspars (booooorrrrriiiiiinnnggg).

For the rest of the SX users, be aware that upon inspecting the window

after replacement, I didn't find any specific pin hole. What I saw looked

like an aging process ... many linear cracks parallel to the support grid

openings. I wouldn't have thought, but my vacuum is orders of magnitudes

better ... pump time, ion pump lookin' good. Anyway, my point for all of you

might be that you might want to put low pressure detector windows on a 4-5

years R&R, at least have a couple handy.



cheers, shaf



<\/>/\<\/>/\<\/>/\<\/> cognito, ergo zZOooOM <\/>/\<\/>/\<\/>/\<\/>

Michael Shaffer, R.A. - University of Oregon Electron Probe Facility

mshaf@oregon.uoregon.edu -or- mshaf@darkwing.uoregon.edu

http://darkwing.uoregon.edu/~mshaf/epmahome/