IMPORTANT : High voltage clarification

James Conway jwc at
Thu Mar 18 10:40:23 PST 2004


The only way to bring up the acceleration voltage on the RAITH 150 
properly is to use the microscope control panel on the Raith150 
application.  This ensures that the voltage ramp is performed uniformly 
with rate ramp control.  This also updated the ELPHY+ pattern generator 
with the dynamic timing parameters for the required pattern 
deconvolution.  This will greatly affect your results for pattern 
placement and scaling information within your EBL write. 
[If you have been observing some strange pattern placement this could be 
one of the reasons.]

IMPORTANT:  PLEASE DO NOT --EVER - adjust the acceleration voltage by 
using the sliders on the SEM control panel --> Gun Tab on the LEO.  This 
will not perform a uniform ramp to set voltage on some rare occasions  
can induce an EHT trip. 

Thank you for your support!


David Goldhaber-Gordon wrote:

>Hi all,
>Thanks and congratulations are due to James for pushing so hard to get the
>system up before he leaves for Germany.
>I want to clarify one point: James probably meant that the voltages me may
>use are 10-15 kV or 20.1 to 21 kV (i.e. 20100 to 21000 V). I point this out
>since the actual numbers may be important and we would hate for someone to
>misunderstand and jeopardize the system for him- or herself and others.
>James, please post a correction if I got this wrong. Also, could someone
>comment on the proper procedure for getting up to those voltages? I'm not
>sure that procedure has been uniformly agreed upon and communicated.
>David Goldhaber-Gordon                         goldhaber-gordon at
>Assistant Professor of Physics                 davidg at
>Stanford University                            (permanent forwarding)
>(650) 725-2047 (lab)                           (650) 724-3709 (office)
>Address for letters or packages:               Administrative Associate:
>David Goldhaber-Gordon                         Roberta Edwards
>Geballe Laboratory for Advanced Materials      McCullough, Rm. 338
>McCullough Building, Room 346                  Phone: (650) 723-8028
>476 Lomita Mall                                Fax: (650) 724-3681
>Stanford, CA 94305-4045                        email: redward at
>-----Original Message-----
>From: James Conway [mailto:jwc at] 
>Sent: Wednesday, March 17, 2004 8:25 PM
>To: John Cumings
>Cc: Raith SNF Mailing list
>Subject: Re: Raith is being qualified... Thread: Required Limits of keV
>operation through 6APRIL2004 on RAITH 150
>Please Everyone:
>We would like to operate the system in a range between  10 - 15 KeV and/or
>at 20100 to 2100 kV only. NOT 20 kV or higher than 21 kV.
> When  I return from Germany and with LEO field service we will perform
>further testing on the column.  
>Things are in good order and tomorrow I plan to put the system back into
>green light mode as more measurements and imaging is completed
>Stitching Mean + 3 sigma was 19 nm.
>Thanks to everyone for your support during this challenging period,
>John Cumings wrote:
>Green light means 30 kV is okay.
>I presume you mean yellow light, because 30 kV is not okay, correct?
>     John Cumings
>     cumings at 
>     Postdoctoral Scholar
>     Physics Department
>     Stanford University                        
>     office (650) 725-1025
>     lab (650) 725-2047
>     fax (650) 724-3681
>     Geballe Laboratory for Advanced Materials
>     239 McCullough Building
>     476 Lomita Mall
>     Stanford, CA 94305-4045
>In message <4058B6CE.7060400 at>you write:
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>I am most relieved to report that we are coming back into normal
>operational status on the RAITH 150 system.<br>
>This afternoon and evening we will be qualifying the system and working
>with users whom are in crisis mode.<br>
>We hope to go into green light mode in the next twelve hours.<br>
>James Conway<br>
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