[Sneap] Focus resistor, Pd leak on AN2500
Chris Westerfeldt
cwest at tunl.duke.edu
Sat Sep 29 08:09:24 EDT 2007
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 1-1/2² long.
I don¹t 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:
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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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