Hi Brian,

Thank you for your response.

Actually, the vacuum of chamber is very good. The arcing is not from the
chamber, it is from the HTSU high tension control unit. We disconnected the
feedthrough of high voltage and filament to the chamber (which means we isolate
the chamber with HT control unit), but we still can hear the arcing when we
turned on the HT over 10KV.

Thanks,

Du


-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Brian Stahl
Sent: Thursday, March 12, 2009 10:51 AM
To: General MEMS discussion
Subject: Re: [mems-talk] Philips XL 30 ESEM HTSU Arching Over 10kV

Hello Du,

Do you only encounter this arcing issue when running the microscope in
environmental SEM mode?  If so, it probably means your chamber pressure is
too high and the water vapor (or whatever gas you're flowing) is ionizing.
Try reducing the pressure in your chamber.

Good luck,

Brian C. Stahl