Important: High voltage clarification

James Conway jwc at snf.stanford.edu
Thu Mar 18 10:42:11 PST 2004


Very well said - Thank you.

Additional post on this thread slowly moving through the mail spooling 
cue...

Thank you,

JWC


Ji-Won Son wrote:

> Hi all,
>
>  
>
> I asked the procedure to use voltage around 20keV, so I think I can 
> answer some of David's question.
>
>  
>
> The Raith system use 8kV deceleration up to 20keV, so the actual 
> voltage that applied to the gun is plus 8V to the acc. voltage you 
> choose. (if you use 20keV, then the actual voltage is 28 V, not 20.)
>
>  
>
> Above 20kV, the system turns off 8V deceleration part and applied 
> voltage will be same as you choose. That's why James asked us to use 
> 10-15 kV and 20.1 - 21 kV at this point to reduce the load.
>
>  
>
> I am not sure about using 10-15kV, but when you use 20.1-21kV, the 
> procedure is:
>
> 1. Turn the beam on at 10kV.
>
> 2. Check the vacuum. (should be around 10^-9)
>
> 3. If vacuum is ok, then change the voltage to 20.1-21kV, by one step. 
> Don't ramp up slowly step by step!
>
>  
>
> These are what I heard from Raith field service. James, if there is 
> anything wrong with these, please correct.
>
>  
>
> Thank you.
>
>  
>
> ====================
>
> Sincerely,
>
> Ji-Won Son
>
>  
>
> (Office) 650-723-4940
>
> (Fax) 650-725-3459
>
> ====================
>
>  
>
> -----Original Message-----
> From: David Goldhaber-Gordon [mailto:goldhaber-gordon at stanford.edu]
> Sent: Thursday, March 18, 2004 6:56 AM
> To: 'James Conway'; 'John Cumings'
> Cc: 'Raith SNF Mailing list'
> Subject: Important: High voltage clarification
>
>  
>
> 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 I'd 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.
>
>  
>
> Best,
>
>  
>
> David
>
>  
>
> ----------------------------------------------------------------------------
>
> David Goldhaber-Gordon                         
> goldhaber-gordon at stanford.edu
>
> Assistant Professor of Physics                 davidg at post.harvard.edu
>
> Stanford University                            (permanent forwarding)
>
>                                                www.goldhaber-gordon.com
>
> (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 stanford.edu
>
> -----Original Message-----
>
> From: James Conway [mailto:jwc at snf.stanford.edu]
>
> 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,
>
>  
>
> JWC
>
>  
>
>  
>
> John Cumings wrote:
>
>  
>
> James,
>
>  
>
> Green light means 30 kV is okay.
>
>  
>
> I presume you mean yellow light, because 30 kV is not okay, correct?
>
>  
>
> -John
>
>  
>
> ------------------------------------------------------------
>
>      John Cumings
>
>      cumings at stanford.edu
>
>      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 snf.stanford.edu>you write:
>
>  
>
> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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> <br>
>
> Greetings:<br>
>
> <br>
>
> I am most relieved to report that we are coming back into normal
>
> operational status on the RAITH 150 system.<br>
>
> <br>
>
> This afternoon and evening we will be qualifying the system and working
>
> with users whom are in crisis mode.<br>
>
> <br>
>
> We hope to go into green light mode in the next twelve hours.<br>
>
> <br>
>
> James Conway<br>
>
> </body>
>
> </html>
>
>  
>
>    
>
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