Date: Fri, 18 Feb 2005 08:58:38 -0500

Author: sampere

Subject: Re: electroscope


They experimenting with some kind of straw tube detector. They
pressurize these tubes with some gas, not sure what yet, but they hold a
high pressure without bursting. There's a fine wire running the length
of them. If this project gets funding, they expect to 12,000 feet (where
are the MKS units?) of this stuff. So there will be plenty to have.

I'll post a pic later.


Wolfgang Rueckner wrote:

> Sounds like a neat electroscope, Sam. What are these "straws"
> actually used for in HEP? -- Wolfgang
> On Feb 17, 2005, at 4:40 PM, sampere wrote:
>> I just made a pretty neat electroscope that's visible and works
>> incredible well. I stumbled across this straw material in the shop
>> last week on one of the benches. I ask a few questions and find out
>> it's conductive, so I take a piece. I cut some aluminum sheet with
>> some shears and punch a few holes and fabricate essentially a Braun
>> electroscope in all of about 5 minutes. The straw is shiny and about
>> 1/4" OD, so it's pretty visible all by itself, but glue a couple
>> mylar flags at each end and the thing is very visible! The straws are
>> 7 micron thick kapton walls coated on the inside and outside with a
>> copper film and weighs next to nothing. A stainless steel pin is the
>> pivot. The lengh of this straw is about 15", so even small angular
>> deflections are easily seen.
>> I used it today for the parallel plate capacitor demo - worked great.
>> No more gold leaf electroscopes!
>> Depending on what happens to federal spending on HEP dictates whether
>> we'll have tons of this stuff around or not. If we eventually get
>> tons, I'll share, in the meantime, go snooping around your HEP labs.
>> Sam
From Fri Feb 18 09:17:55 2005