[Sbs] news and listservs

[Cynthia (Thia) Keppel]

Greetings SBSers,

I've heard concerns from a few of you today about the recent emails on this list (or the causes thereof). Amazingly, this let me discover that I am not on the SBS e-list!

So, I am taking full advantage now of my new-found ability to write to you en masse to say...

THANK YOU!! This late Hall closure is a really hard time and clearly patience is wearing thin. People are working diligently to make the SBS program happen, and every contribution of long hours, hard work, and expertise is greatly appreciated. Let's strive to make sure that the high value we all place in one another, hard-earned from toiling together towards a mutual goal, is continually evident in our behavior.

But... is an e-list the place to say this? No? No. Right, so what should I be saying...?.. I know!...

Technical news! As you know, our latest delay has been due to fighting a vacuum problem in the downstream beam line. The quite aged and much-patched Hall A corrugated beam pipe is very leaky and, moreover, we don't trust it not to spring new vacuum leaks when we maneuver around it for small angles of the SBS spectrometer (which the pipe goes directly through). So...

We decided today to reconfigure a region of beam pipe near (but downstream of) the target chamber to have a differential pumping region. This will have two Aluminum plates with circular holes for the beam, with a turbo pump port between them. There's also a bellows and a manual gate valve. We have all of these pieces/parts on hand, except the plates to be machined and one off-the-shelf valve. This new differential pump approach should afford some insurance against run down time after changeovers, so it's both a better and faster fix than chasing the (possibly multiple) unknown leaks in the downstream pipe.

Thank you all again again,
Thia


Cynthia Keppel, PhD

Hall A and C Leader

Thomas Jefferson National Accelerator Facility

1-757-269-7580
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