PHENIX & The Beam Pipe

1)Overview of the drawings 2)I will break down the beam pipe going from MuID-S to MuID-N piece by piece. 3)Important Information 4)Overview of the planned changes to the PHENIX beampipe.

PHENIX w/ focus on the beampipe This is from an Autocad drawing done by Richie and Don: 026.pdf Part F no longer exists. This was a stand used before the South Magnet was installed.

South Piston Hole Beampipe This is from an Autocad drawing done by Richie and Don. A pdf copy is available: 047.pdf Zoom-ins and explanations will follow.

North Piston Hole Beampipe This is from an Autocad drawing done by Richie and Don. A pdf copy is available: 038.pdf Zoom-ins and explanations will follow. And theres a bellows, but it doesnt have a Bellows Spreader on it. The Souths bellows spreader increases the Souths keep out zone.

South Mu ID Valve – isolates PHENIX from the rest of the ring. Close the valve, and we can break vacuum without affecting the ring. Bellows – I & 2 BPM – beam position monitor Vacuum Pump

Fixed support – no longer exists. Taken out with installation of South Magnet Sliding Beam Pipe Support Shown in Section C of 026.pdf Flange and Bellows Shown in Detail D of 026.pdf & in 047.pdf Conversion from 5 ID to 3 ID steel beam pipe South Muon Magnet

Beam pipe conversion from steel to beryllium. This is a rigid joint. I believe the transition from beryllium to steel is inside the central magnet steel Central Region

V – Shaped support : The steel beam pipe is not rigidly held here. Nor can it roll. It can scrape through the V. Flange and Bellows Conversion from 3 ID to 5 ID steel beam pipe North Muon Magnet Sliding Beam Pipe Support Shown in Section C of 026.pdf

North MuID Very similar to the South case. Valve, flanges, vacuum pump…

Important Information There must be a bellows between any two fixed points to give the beam pipe room to expand/contract in the z-direction. Fixed Point Rolling Support Bellows From 026.pdf it looks like this is a non-sliding support, positioned just before the transition to beryllium. This seems to break the rule. I will follow up with Don tomorrow. Sliding Support

Three Beam Pipes Beryllium section is rigidly connect to steel piece.

Planned Changes Both the beampipe thickness and inner diameter will be decreased. Time frame unknown, but it is connected with the Nose Cone Calorimeter upgrade. The plan is to have beryllium up to the nose cone, have a bellows there and make the transition to steel. Its difficult to tell, but it looks like the current beampipe makes the steel-beryllium transition inside the central magnet We could make the argument that we are moving the south bellows from the magnet hole to the south nose cone.

What would this give us? Bellows Spreader Diameter – 6.50 Flange Diameter – 4.62 Wed reduce the keep out zone radius by almost an inch so… wed be at the keep out zone of the North MPC… 4 5/8 The south drawings are in pdfs 043, 044, 045, 046 & 047.

Numbers Explained (i) is diameter of spreaders 5.5 is the diameter of the circle formed by the bellow spreader rods

Numbers Explained (ii) 4.62 is the flange diameter. – This would make out keep out diameter the same as the NMPC.