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-in’s 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.pdfZoom-in’s and explanations will follow.

And there’s a bellows, but it doesn’t have a “Bellows Spreader” on it. The South’s “bellows spreader” increases the South’s 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 SupportShown in Section C of 026.pdf

Flange and BellowsShown 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 SupportShown 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. It’s 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”

We’d reduce the keep out zone radius by almost an inch so… we’d be at the keep out zone of the North MPC… 4 5/8”

The south drawings are in pdf’s 043, 044, 045, 046 & 047.

Numbers Explained (i)

6.5”

6.5” 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.