Jim, Wow, there are a lot of details there. Do you have a drawing to go along with these words? My feeling is that there is no one else thinking about this design at the level you are here, so you really have a free hand to go ahead with this design based on the top-level concept we currently have. This looks like what you are doing. Can I suggest the following? On the gluex wiki (http://wiki.gluex.org) under the heading "Photon Beam" I have created a new link in the right-hand list called "Photon beam pipe". Right now it is a blank page. Can you create that page and upload the text of your email there for all of us to review in the working group? At the same time, if you could post a descriptive drawing, however crude, it would greatly help us to visualize what you are describing. We will then discuss it at our next photon beam working group meeting. thanks, Richard Jones 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 > > > >
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