[labnetwork] troubleshooting an e-beam source

[James Mitchell]

Have you tried rebuilding the gun assembly? Sometimes the ceramic pieces
get too much metal on them and cause a short.
Replace all the ceramics and make sure your filament has good clearance.
Some filaments can only go in one way because of the coil direction.

Jim

On Thu, Jul 8, 2021 at 3:57 PM Nathanael Sieb <sieb at 4dlabs.ca> wrote:

> Hi all,
>
> We are trying to trouble-shoot a PVD e-beam source and can't seem to
> figure out the problem.  Early in the year we sent the assembly out for
> repair and refurbishment. (we burned a hole in the internal bellows tubing,
> long story)  When we got it back we connected it back to the system and
> started it up.  However, we haven't been able to get a stable emission
> current.  The HV stays on but the filament current, and hence emission
> current, occasionally cuts out.  It comes back a second later, over-shoots
> the target current, and then restabilizes.  It happens at low emission
> currents and some higher ones.  The timing is random.  Sometimes it happens
> frequently, sometimes you can run 15 min without a problem.  There are no
> errors from the power supply.
>
> We took a video of the issue and it happens at around the 1min mark here
> <https://www.dropbox.com/s/7n42e38qviju7ga/Both_emission_and_filament_spiking_and_turning_off.mov?dl=0>.
> The advice from vendors was to look for a loose connection.  We have
> checked all the external connections and tried to look at the internal ones
> too.  Last week we removed the filament and reinstalled it.  We didn't see
> any problems and we still have the same issue.
>
> We're running out of ideas other than sending it back to the vendor to
> examine the entire assembly again.  Has anyone else encountered this type
> of problem?  Any suggestions?
>
> Thanks,
> Nathanael
>
> * Nathanael Sieb *
> Director of Operations and Administration  |  4D LABS
> <http://www.4dlabs.ca/>
> Simon Fraser University
> 8888 University Dr., Burnaby, B.C. V5A 1S6
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-- 
*James Mitchell*
*Specialty Trades Technician*
*Dept. of Electrical and Computer Engineering*
*NCSU Nanofabrication Facility*
*MRC RM243A **Box 7911*
*2410 Campus Shore Dr., Raleigh, NC 27606*
*jtmitch5 at ncsu.edu* <jtmitch5 at ncsu.edu>
*Desk: 919-515-5394*
*Cell: 919-717-7325*
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