MPSLogicDocumentation (2).pdf

Logic information in this file describes the MPS implementation.

User Area devices

User Area devices POC is Christine Clarke

User area devices interlocked to MPS comprise:

• OvenBeWindow
• Plasma Oven
• EPS Summary
• Alignment Laser Injection Mirror
• HCOL2072 Klixon

Discussion

The Oven Beryllium window is on a valve body (device VVPG:LI20:3202). When it is moving (not in, not out) we require that beam is inhibited (0 Hz). We are concerned about damage to its sealing surface. Spares exist so the consequence is not high.

The plasma oven is shown below. It could be in two positions. When the oven is moving or not fully in or out, we require the beam is inhibited (0 Hz) such that the beam does not hit the beamline components and potentially open up a leak to air.

Also, if the oven position is in, we want to protect the gate valves from beam. The MPS does not know the position of the gate valves but the EPS (Experiment Protection System) does. The EPS therefore provides the MPS with an OK. The OK is “gate valves are open” or “oven is out”. Therefore, if the oven is in the “in” position but the valves are closed, the EPS does not give an OK and the beam needs to be inhibited (0 Hz). The oven could be contaminated with air if the gate valves are damaged or a leak is opened up by mis-steering into the pipe. The electron beam will be at a focus here and at its most destructive. The oven is not easy to replace- it would take months to build a replacement. So the severity is high here.

Above figure: E-300 oven and bypass line. This is on a mover such that the experimenter can move the oven into the beam path or the bypass line into the beam path remotely. Large 8 inch bellows are on either end (not shown). The oven will only be inserted by the experimenter as part of their approved experiment procedure. When the oven is not in use, which is most of the time, the electron beam will go through the bypass line. MPS has dedicated switches for each position (oven and bypass).

The alignment laser injector mirror is a pneumatic device operated by OTRS:LI20:3158:PNEUMATIC. It is physically a 45 degrees mirror. A diode laser (low power) can be injected co-linear with the electron beam trajectory when the mirror is inserted. We use this for alignment of optics inside the vacuum chambers for the experiment. The mirror is only to be inserted when the beam is not present. The consequences are damage to the mirror (low impact- it’s easy to replace) and the creation of showers that can damage cameras (low impact- they are easy to replace).

Klixons are on the jaws of the S20 jaw collimator. The two klixons are wired in series. The jaw collimator is expected to operate with water cooling and the klixons indicate failure of water cooling. It is not clear to me that this is a critical interlock as now beam power is considerably reduced and it would only be ~30 W deposited in the jaw, not enough to cause damage. We could consider removing this interlock? Note: the notch collimator is not water cooled.

Email from Dieter on Jaw collimator water cooling (10/24/2011):

The jaw length of the power absorption or collimating portions of the former FFTB MOMENTUM SLIT (this is not the notch collimator that makes two bunchlets out of one bunch) is ~ 4 Xo of titanium (attached to water cooled copper heat sinks).

For 22 GeV beams with 2x10^10 electrons/ bunch and 30 Hz ( ~2kW), and the whole beam intercepted by one jaw, the amount of power actually deposited in that jaw is ~ 15% or < 400 W.  I would be happy if we had a flow rate if ~ 0.1 gpm  for each jaw, and 0.2 gpm