Re: beamline

[Elton Smith <elton@jlab.org>]

HI Jim,

Some useful information on the personnel and machine protection systems
can be found at http://www.jlab.org/accel/ssg/12gev/12gev_home.html.

Cheers, Elton.





Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625
(757) 269-6331 fax

On Fri, 11 Apr 2008, Jim Stewart wrote:

> Dear Richard
>
> Could you look this over? As I just started I suspect I have overlooked a
> lot.
>
> I wanted to start with something easy so I decided to look at the beamline
> in the tagger hall. Just for the hell of it I decided to start at the 10"
> pipe in the tagger hall.
>
> This is a 10" schedule 40 stainless steel pipe terminated with a 13-1/4"
> conflat flange. It sticks out from the wall 1' and when we receive the
> hall it will be blanked off.
>
> 10" is really big so we should immediately reduce down. I propose we mount
> a 1' long reducer from 13-1/4 to 4-5/8" cf made with 3"OD stn.stl. tube.
> 3" is a convenient size pipe as it is self supporting. This helps later.
>
>
> This is followed by a 4-5/8" tee which we need to connect a pump.
> On the side flange we can connect a zero length reducer to go to 2-3/4" cf
> and then a hybrid adapter to go to an NW-40 ISO-K fitting. From ISO-K
> everything is easy. We need 1 tee with a valve so we can connect a
> portable JLAB roots pump when we want to pump down the system. Then
> another tee for a convectron pressure gage ($360 good down to 10^-3
> Torr) and a valve to a pump station. Tim recommends a pfeiffer turbo pump
> station. The turbo pump stand costs $5.5K but is a self contained plug and
> play unit with minimal maintenance. It is also clean so there are no
> worries about getting oil where we don't want. The pfeiffer turbos with
> a DIN40 flange have a pumping speed of 33l/s. If we go to a DIN63 it goes
> up to 59 l/s.
>
> Back to the beamline.
>
> After the tee comes a short metal bellows. The MDC 4-5/8" bellows has a
> free length of 7-1/4".
>
> We are now 1'+1'+7-1/4+7-1/4 = 38.5 or 3' 2-1/2" from the wall. I hope
> this is OK.
>
> Then we can put a straight piece of 3"OD pipe up to the permanent magnet
> dipole.
>
> The upstream end of the permanent magnet is 42'-8 1/4" from the downstream
> wall. I hope the means the start of the iron. The iron is 145" long and we
> need about 3" to get to the vacuum flange. The pipe in the magnet is an
> elliptical 3-1/2" by 1-1/2" pipe. 3 1/2" is too big for the 4-5/8" cf. As
> we don't care about pumping speed we can make an adapter to go from the
> elliptical to 4" OD pipe then adapt to 3inch OD pipe and put the 4-5/8" cf
> on the end of the 3" pipe. 4" is comfortable for this. We anyway have to
> cut and weld on the elliptical beam pipe so this is not too much work.
>
> Assuming all the above then the downstream flange of the permanent
> magnet is 42'-8 1/4" - 145" - 4" = 363.25 or 30'-3 1/4 inches from the
> downstream hall wall. Just to be sure we can put another 4-5/8" bellows
> here to make it easy to connect the flanges.
> The beam pipe is then 363.25 - 38.5 -7-1/4" = 307.5" or
> 25'-7 1/2" long. I guess we need 3 supports going to the floor.
>
> To keep things symmetric we should do the same on other side of the
> dipole. Assume 4" to adapt to 4-5/8 cf. Then I would put a zero length
> reducer on to go to 2-3/4". This changes diameter so you need to take up
> the vacuum force. I guess we can add a bracket to the dipole iron and use
> the dipole support to take up the force.
>
> We can mount a 2-3/4" flexible coupling onto this which takes up 3-1/2".
> Then I would put a gatevalve and what I am guessing is 7' of 1-1/2" pipe.
> This should get us close to the tagger vacuum vessel. This is where I run
> out of concrete number. The 1-1/2" pipe 7' long will have a conductance
> for air at 20C of about 1.8 l/s so it will give us a bit of a differential
> pumping system.
>
> This has no windows up to the goniometer. Is this what we want?
>
> I am using conflat because I like conflat. Once you leak chase the
> connections you can forget about them forever.
>
>
>
> Jim
>
>
>
>