[Sneap] Focus resistor, Pd leak on AN2500
jim
starkj at execulink.com
Sat Sep 29 22:59:59 EDT 2007
Re: [Sneap] Focus resistor, Pd leak on AN2500 Chris
I think they are 10 Kv as you mentioned, 10 W, very stable and live forever. I think we had a box of them at Mac still in the old column resistor casings used in the original KN machine 1954 vintage they used to use a string of them. Years ago I made holders to extend the old FN yellow stick 400M resistors to fit a KN at Defense in Ottawa. They were surplus to us as we had changed to the caddock serpentine design so we manufactured the old ones that had not degraded very much for that machine, and it many years later, is still running reliably at 3MV
See you all at SNEAP.
Cheers Jim
----- Original Message -----
From: Chris Westerfeldt
To: Symposium of Northeastern Accelerator Personnel
Sent: Saturday, September 29, 2007 8:09 AM
Subject: Re: [Sneap] Focus resistor, Pd leak on AN2500
The ATF-SNEAP 2006 meeting was held in Australia and information is available at:
http://www.ansto.gov.au/nugeo/conference/private/ATF_SNEAP.htm
++++++++++++++++++++++++++++++++++++
The SNEAP 2007 meeting will be hosted by Brigham Young University in Salt Lake City Utah. The meeting web site is located at:
http://webpub.byu.net/wsd/.
The 41st SNEAP Conference
Brigham Young University
October 7 - 11, 2007
Please note:
DUE TO THE ORIGINAL ANNOUNCEMENT BEING LOST IN CYBER-SP[ACE, THE
SUBMISSION DATE HAS BEEN EXTENDED TO September 15th
Call for Papers:
Brigham Young University in sponsoring the 41st Conference of the
Symposium of North Eastern Accelerator Personnel (SNEAP) on October 7-
11, 2007. The conference will be held at the Embassy Suites Hotel in
Salt Lake City, Utah.
The SNEAP Conference is directed toward scientists and technical staff
who are involved in developing, upgrading, and operating electrostatic
accelerators. Further information about the conference is available at
the conference website:
http://webpub.byu.net/wsd.
We invite presentations on topics relating to accelerator design,
operation, and improvement, and to unresolved problems with accelerator
systems. Please send a title and abstract of your proposed presentations
to sneap at byu.edu by September 15.
Contacts:
Scott Daniel wsd at byu.edu
Lawrence Rees sneap at byu.edu
------------------------------------------------------------------------------
Thanks Jim. For the younger crowd out there - I just happen to have a box of SS White resistors. Here is what Jim is talking about - see attachment.
They are molded composition resistors. The hexagonal body is 1-1/2" long. I don't know what the actual voltage rating for these was
but it must have been around 10 KV - Jim , do you know any details? The JN resistors I posted are full of these ( they have been spoken for by the way).
- Chris
--
Chris R. Westerfeldt
Research Scientist / T.U.N.L. Radiation Safety Manager
Duke University Physics Department &
Triangle Universities Nuclear Laboratory
Science Drive, Box 90308
Durham, NC 27708-0308
Tel: (919) 660-2600
Fax: (919) 660-2634
Email: Cwest at Tunl.Duke.Edu
------------------------------------------------------------------------------
From: jim <starkj at execulink.com>
Reply-To: Symposium of Northeastern Accelerator Personnel <sneap at tunl.duke.edu>
Date: Fri, 28 Sep 2007 21:23:36 -0400
To: Symposium of Northeastern Accelerator Personnel <sneap at tunl.duke.edu>
Subject: Re: [Sneap] Focus resistor, Pd leak on AN2500
The ATF-SNEAP 2006 meeting was held in Australia and information is available at:
http://www.ansto.gov.au/nugeo/conference/private/ATF_SNEAP.htm
++++++++++++++++++++++++++++++++++++
The SNEAP 2007 meeting will be hosted by Brigham Young University in Salt Lake City Utah. The meeting web site is located at:
http://webpub.byu.net/wsd/.
The 41st SNEAP Conference
Brigham Young University
October 7 - 11, 2007
Please note:
DUE TO THE ORIGINAL ANNOUNCEMENT BEING LOST IN CYBER-SP[ACE, THE
SUBMISSION DATE HAS BEEN EXTENDED TO September 15th
Call for Papers:
Brigham Young University in sponsoring the 41st Conference of the
Symposium of North Eastern Accelerator Personnel (SNEAP) on October 7-
11, 2007. The conference will be held at the Embassy Suites Hotel in
Salt Lake City, Utah.
The SNEAP Conference is directed toward scientists and technical staff
who are involved in developing, upgrading, and operating electrostatic
accelerators. Further information about the conference is available at
the conference website:
http://webpub.byu.net/wsd.
We invite presentations on topics relating to accelerator design,
operation, and improvement, and to unresolved problems with accelerator
systems. Please send a title and abstract of your proposed presentations
to sneap at byu.edu by September 15.
Contacts:
Scott Daniel wsd at byu.edu
Lawrence Rees sneap at byu.edu
------------------------------------------------------------------------------
Hi Stuart
Well going back in time for me to palladium leaks, the common failure was poisoning of the palladium from bad gas or leaks to the palladium when switched off SF6 for us leaking into the source then back to leak I suspect, which gives you no leak rate, or cracking the palladium which can leave you with a small leak until heated which rises rapidly or flooding your source with a small amount of heat applied.As to the leak rate when not heated palladium or T.M. leaks, the leak detectors we had at the time would not show much of anything not to say there wasn't gas coming through, as we could see in the colour of the strike while in the machine. Not much help with that. To the resisitor. We used old carbon resistors and never found them to devalue to my knowledge. Years ago people had lots of old parts around, they are not as readily availble anymore. Anyone who has old SS White resistors should list them with SNEAP they are always useful.
Good Luck
----- Original Message -----
From: Van Deusen, Stuart B <mailto:sbvande at sandia.gov>
To: SNEAP at tunl.duke.edu
Sent: Friday, September 28, 2007 11:08 AM
Subject: [Sneap] Focus resistor, Pd leak on AN2500
The ATF-SNEAP 2006 meeting was held in Australia and information is available at:
http://www.ansto.gov.au/nugeo/conference/private/ATF_SNEAP.htm
++++++++++++++++++++++++++++++++++++
The SNEAP 2007 meeting will be hosted by Brigham Young University in Salt Lake City Utah. The meeting web site is located at:
http://webpub.byu.net/wsd/.
The 41st SNEAP Conference
Brigham Young University
October 7 - 11, 2007
Please note:
DUE TO THE ORIGINAL ANNOUNCEMENT BEING LOST IN CYBER-SP[ACE, THE
SUBMISSION DATE HAS BEEN EXTENDED TO September 15th
Call for Papers:
Brigham Young University in sponsoring the 41st Conference of the
Symposium of North Eastern Accelerator Personnel (SNEAP) on October 7-
11, 2007. The conference will be held at the Embassy Suites Hotel in
Salt Lake City, Utah.
The SNEAP Conference is directed toward scientists and technical staff
who are involved in developing, upgrading, and operating electrostatic
accelerators. Further information about the conference is available at
the conference website:
http://webpub.byu.net/wsd.
We invite presentations on topics relating to accelerator design,
operation, and improvement, and to unresolved problems with accelerator
systems. Please send a title and abstract of your proposed presentations
to sneap at byu.edu by September 15.
Contacts:
Scott Daniel wsd at byu.edu
Lawrence Rees sneap at byu.edu
----------------------------------------------------------------------------
Hello all
The output from the focus power supply on an AN2500 goes through a resistor on its way to being clipped to the focus plane on the column. The HVEC circuit diagram shows this as a 2 Mohm resistor. When I started operating my machine 11 years ago, it was equipped with a string of 2W carbon composition resistors totaling about 11Mohm. I recently managed to blow these resistors up (probably by arcing over) by running the focus voltage too high while the machine was in normal operation. I replaced the string of carbon composition resistors with a single thick carbon film resistor, rated at 5W and 20 KV. I find that after some use, the value of the resistor drops, in the most recent case by almost half. I don't really understand what is happening to the resistor, and if it will ultimately fail open or not.
My question is, what do you all put in when you replace this resistor?
A second question concerns the palladium leak used for hydrogen in the AN2500 (and I'm sure other machines as well). Does anyone have experience with these leaks failing, and if so, what is the failure mode? On both this leak and the thermo mechanical leak used for He, what is the expected leak rate when a good leak is fully "closed"?
Thank you for your help.
Stuart Van Deusen
-----------------------------------------------------------
Stuart B. Van Deusen
Radiation Solid Interactions and Processing
Dept. 1111, M/S 1056
Sandia National Laboratories
P.O. Box 5800
Albuquerque, NM 87185-1056
USA
PH (505)844-7782
FAX (505)844-7775
e-mail: sbvande at sandia.gov
address for package delivery:
US NNSA c/o Sandia Natl. Labs
ATTN: Stuart Van Deusen
Bldg. 884, Rm. 11
1515 Eubank S.E.
Albuquerque, NM 87123
USA
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