Interlock logic

The logic of the X-1A interlock is described in detail Appendix E.1. An abbreviated description of the logic is as follows:

Mask/Shutter

One special requirement of the X1 beamline is that uncooled surfaces should not see the full undulator beam. Therefore, the beamline interlock provides the front end interlock system with a normally open relay contact (EMNO/EMC/EMNC) that is closed only when the following conditions are met:

• Cooling water is flowing to the following cooling circuits in the beamline:
  • Beam stop, mirror M0
  • Entrance slit mask, mirrors M1i and M1o, entrance slits (inboard/X1A2 and outboard/X1A1)
• Valves V1 and V2 are open and V1 is not overridden
• If the X-1A mirror M0 is not fully retracted, then valves V3, V4i, V4o, V5i, V5o, V6i, and V6o must be open.
• The EXPERIMENT B MASK relay contact must be closed.

If the above conditions are met, the Shutter Open light (green) will be lit; otherwise, the Shutter Closed light (red) will be lit. In addition, each of the above conditions are indicated by individual front panel lights.

V1

All-metal, pneumatically-operated.
Location: just outside the shield wall.
Interlock: This valve will be made to close if gauges FE or G1 indicate bad vacuum. When this valve is not open or it is overridden, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close. V1 will be closed by a V3 override.

V2

All-metal, manually-operated (viton sealed, 8'' flanges).
Location: between the X-1A and X-1B mirror chambers. Interlock: When this manual valve is not fully open, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close. A limit switch has been installed on V2 for this purpose, so that the valve need not be yellow-tagged.

V3

All-metal, pneumatically-operated.
Location: between the X-1B mirror chamber and the outboard branch toroidal mirror chamber.
Interlock: This valve will be made to close if gauges G2 or G3 indicate bad vacuum. When this valve is not open, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close unless the mirror M0 is fully retracted. V3 will be closed by a V4i or V4o override.

Inboard (X1A2) branch:

V4i

All-metal, pneumatically-operated.
Location: inboard branch, between the outboard branch toroidal mirror chamber and the inboard branch toroidal mirror chamber.
Interlock: This valve will be made to close if gauges G3 or G4 indicate bad vacuum. When this valve is not open, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close unless the mirror M0 is fully retracted. V4i will be closed by a V5i override.

V5i

All-metal, pneumatically-operated.
Location: at exit of inboard branch toroidal mirror chamber.
Interlock: This valve will be made to close if gauges G4 or G5i indicate bad vacuum. When this valve is not open, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close unless the mirror M0 is fully retracted. V5i will be closed by a V7i override.

V6i

Viton sealed, manually-operated.
Location: at entrance to the inboard branch monochromator chamber.
Interlock: This is a manual valve, and it is therefore not interlocked. It will be padlocked open. If it is closed for beamline maintenance purposes, it will be yellow-tagged and our beamline will be locked out.

V7i

Viton sealed, pneumatically-operated.
Location: at exit from the inboard branch monochromator chamber.
Interlock: This valve will be made to close if gauges G6i or G8i indicate bad vacuum, or by a V9i override.

V8i

Viton sealed, manually-operated.
Location: downstream of the inboard branch monochromator chamber, and just upstream of pump P7i.
Interlock: This is a manual valve, and it is therefore not interlocked. If it is closed for beamline maintenance purposes, then V7i must also be closed and both valves must be yellow-tagged for operations coordinator approval before opening. Note: This valve will be closed when the inboard exit slit area ExSi is to be baked out. At that time, V9i will be opened so that the exit slit area ExSi can be pumped by P7i during the bakeout. The pressure on G8i should be below $1 \times 10^{-8}$ torr before V8i can again be opened.

V9i

Viton sealed, pneumatically-operated.
Location: downstream of pump P7i, and upstream of the inboard branch exit slit.
Interlock: This valve will be made to close if gauges G8i, G9i, or G10i indicate bad vacuum, or by a V10i override.

WV

Window valve: viton sealed, manually operated valve with a silicon nitride window in its center.
Location: downstream of the exit slit.
Interlock: This is a manual valve, and it is not interlocked. Its (800 $\mu$m)$^{2}$ silicon nitride window is used to separate experiment vacuum from beamline vacuum for the holography and diffraction experiments. It will be yellow-tagged in the ``closed'' position for SPEM mode, and yellow-tagged in the ``open'' position for the Holography/Diffraction mode.

V10i

Viton sealed, pneumatically operated.
Location: just downstream of the window valve WV.
Interlock in Holo/Diff mode: This valve will be made to close if gauges G9i or G10i indicate bad vacuum.
Interlock in SPEM mode: This valve will be made to close if gauges G9i or G11i indicate bad vacuum, or by a V11i override.

V11i

Viton sealed, pneumatically operated.
Location: just upstream of the SPEM chamber.
Interlock in Holo/Diff mode: This valve will be closed.
Interlock in SPEM mode: This valve will be made to close if gauges G9i or G11i indicate bad vacuum.

Outboard branch:

V4o

All-metal, pneumatically-operated.
Location: outboard branch, between the outboard branch toroidal mirror chamber and the inboard branch toroidal mirror chamber.
Interlock: This valve will be made to close if gauges G3 or G4 indicate bad vacuum. When this valve is not open, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close unless the mirror M0 is fully retracted. V4o will be closed by a V5o override.

V5o

All-metal, pneumatically-operated.
Location: at exit of inboard branch toroidal mirror chamber, just before the outboard branch entrance slit.
Interlock: This valve will be made to close if gauges G4 or G5o indicate bad vacuum. When this valve is not open, the beamline interlock will indicate to the front-end interlock that the mask/shutter should close unless the mirror M0 is fully retracted. V5o will be closed by a V7o override.

V6o

Viton sealed, manually-operated.
Location: at entrance to the outboard branch monochromator chamber.
Interlock: This is a manual valve, and it is therefore not interlocked. It will be padlocked open. If it is closed for beamline maintenance purposes, it will be yellow-tagged and our beamline will be locked out.

V7o

Viton sealed, pneumatically-operated.
Location: at exit from the outboard branch monochromator chamber.
Interlock: This valve will be made to close if gauges G6o or G8o indicate bad vacuum, or by a V9o override.

V8o

Viton sealed, manually-operated.
Location: downstream of the outboard branch monochromator chamber, and just upstream of pump P6o.
Interlock: This is a manual valve, and it is therefore not interlocked. If it is closed for beamline maintenance purposes, then V7o must also be closed and both valves must be yellow-tagged for operations coordinator approval before opening. Note: This valve will be closed when the outboard exit slit area ExSo is to be baked out. At that time, V9o will be opened so that the exit slit area ExSo can be pumped by P6o during the bakeout. The pressure on G8o should be below $1 \times 10^{-8}$ torr before V8o can again be opened.

V9o

Viton sealed, pneumatically-operated.
Location: downstream of the outboard branch exit slit.
Interlock in D-STXM mode: This valve will be made to close if gauges G8o, G9o, or G10o indicate bad vacuum. Interlock in CryoSTXM mode: This valve will be made to close if gauges G8o, G9o, or G11o indicate bad vacuum, if the D-STXM Helium enclosure (``He Box'') is not in place, or by a V10o override.

V10o

Viton sealed, pneumatically-operated.
Location: between D-STXM and CryoSTXM.
Interlock in D-STXM mode: This valve will be closed. Interlock in CryoSTXM mode: This valve will close if gauges G9o or G11o indicate bad vacuum.