Final Design Report
UNICAT Sector 34-ID
1. Changes of scope since the PDR
There have been no changes in the scientific goals outlined in the original Conceptual Design Report (CDR): coherent X-ray diffraction (CXD) will take place on the pink branch line in the 34ID-C hutch and micro-focus diffraction (MFD) will use the white endstation 34ID-E.
Since the original plan, a new option of operating two canted undulators has been made available by APS. This arises because of the possibility of local horizontal steering of the electron beam within each straight section. A prototype is already under construction at ID4 (SRICAT). Our plan to implement this option was also discussed with the PEB in February 1999, and was encouraged.
Two canted undulator A's can be accommodated by our original beamline design (described in the PDR) without any fundamental design change, provided we limit the total power by setting minimum gap of 11mm for each one. The current vacuum chamber has an 8mm aperture and only allows an 11mm minimum gap anyway. With suitable administrative controls, one (but not both) undulator could in principle be closed below 11mm. We had originally planned to seek a 2.5m undulator with a 27mm period to best match the spectral requirements of our experiments, and we would like to retain that option, subject to the power-handling limitations of the beamline design.
Specifically, in the PDR, we designed for a power density level of 230kW/mrad2. Two closed gap (11mm) undulator A's without canting would produce 280kW/mrad2, representing a 22% increase. The power-limiting component is the P9-30 photon shutter of the white-beam branch, for which we (conservatively) calculated a temperature rise of 430
° C at the center of its illuminated spot. Increasing this to 520° C would still be safely below the melting point of copper (Glydcop). The total power load would increase from 178W to 217W, but is still well within the 600W rating of the P9-30. In practice, the canting would be under administrative control and would never be turned off. Since the undulators would be only be allowed to fully close when the canting magnets were turned on, we would never reach the 280kW/mrad2 level.In order to accommodate the canted configuration, we have enlarged the aperture of the M4-20 mask from 3mm(H)
´ 2mm(V), as described in the PDR, to 4mm(H)´ 2mm(V). We will be able to utilize a canting of 110m rad between the axis directions of the two undulators. This would achieve a 3mm separation between the beams at the M4-20 aperture located at 27m. This is considerably less than the 270m rad permitted at sector 4, which cleanly separates the central cones of the two beams. Instead, at 110m rad, we would have to accept a small amount of spectral interference between the two beams. The two undulator gaps would be controlled independently by the two tandem experiments; one broadband experiment would experience a few percent flux enhancement from the other undulator with relative energy components changing by as much as 1% as its gap is changed. For most experiments this would be tolerable, and would certainly be a huge improvement over having a compromise gap setting on a single undulator.We would like to make clear our intention to install a second undulator, canted with respect to the first, at some future time. We cannot estimate the time frame for this upgrade because it will require new funding to purchase the second undulator.
There are a few other minor design changes from the description in the PDR. There is an increase of the inner diameter of the long white beam transport from 16mm to 30mm to make its alignment less critical; this is described in detail here. There have also been some small changes in the positioning of components along the beamline, mainly associated with the detailed hutch designs, also described in detail here. These changes affect the Bremsstrahlung and SR ray-tracing drawings almost imperceptibly, but the current versions are included for inspection.
In this final design report (FDR) we present the detailed designs of all the remaining components that were not designed at the time of the PDR. Updates to the designs already approved are given in a separate section. The hutch specifications (see Appendix A) were both written and reviewed separately from the PDR and are not repeated here either, except in functional summary form. In this way the combination of PDR + FDR + hutch specs constitutes a complete description of the 34ID beamline. The PDR and Hutch specs are therefore also appended to this document.
2. Current beamline floor plan
No significant changes have been made to the sector layout since the publication of the PDR. Figure 1 shows the general beamline layout. An independent control area is required for each of the two experimental hutches. The instrumentation for the coherent scattering station will be clustered around the door of 34-ID-C, while the micro-focus experiment controls will sit along the wall of 34-ID-E, just downstream of the door. The standard egress aisle runs between sector 34 and sector 35, with a secondary egress aisle provided by a duck-under point connecting the sector 34 aisle with the sector 33 aisle.
3. Updates to component designs already approved in PDR
M4-20 in 34-ID-A
The standard M4-20 mask that protects the K3-22 collimator and L5-90 slits in the FOE was ordered and built with a 4mm(h)
´ 2mm(v) aperture instead of the 3mm ´ 2mm aperture proposed in the PDR. As mentioned in the introduction, this change anticipates the use of canted undulators supplying the two separate branches of 34ID. The increased width does not affect the shielding scheme show in the ray tracings, because the following K3-22 has a 6mm internal aperture. The change in the thermal-loading calculations has been taken into account.
K3-22 in 34-ID-A
The bremsstrahlung collimator that shields the first white beam transport is a K3-22 collimator with a 6mm diameter aperture (reduced from the standard 12mm) that sits 26.9m from the source. The maximum excursion of the bremsstralung radiation at this point is 199mm(h)
´ 47mm(v), while the radius of the tungsten cylinder in the K3 is only 50mm. Lead blocks, 100mm wide ´ 140mm high, will be placed behind the K3 on both sides to cover the remainder of the bremsstrahlung. It will be covered entirely with plexiglass and labeled as a configurational control item. Figure 2 shows a cross sectional schematic of the collimator and lead blocks with a projection of the maximum bremsstrahlung excursion.L5-90 in 34-ID-A
Slight changes in the design of these slits were required at the time of fabrication. There had been found to be corrosion problems associated with allowing direct contact of the DI cooling water with the reamed tungsten cooling channels; the corrosion problem was fixed by the use of steel inserts. Otherwise the L5-90 follows the standard design of the DX.
Mirror in 34-ID-A
No conceptual changes have been made to the mirror design since the PDR was submitted, but the size of the silicon substrate has been increased and the geometry of the liquid nitrogen feed has changed.
The original mirror substrate was to be thin (~15mm in depth) and held in a mount that in cross section looked much like a C-clamp. Following the advice of Ali Khounsari, it was decided that a thin mirror might deform in such a mount, so a more robust configuration was developed. As built, the mirror substrate is a 30 ´ 30 ´ 220 mm3 silicon block with vertical holes bored through the center to pass ¼" bolts, which clamp the mirror to the copper cooling block. Figure 3 shows a cross section of the mirror in its mount. Belleville spring washers are used on each bolt to evenly distribute the clamping force and allow for differential expansion between the stainless steel bolts and the silicon as the assembly is cooled. A thin indium sheet is compressed between the silicon and the copper to enhance thermal conductivity.
In conjunction with the change in the mirror mount, a simpler LN2 delivery system has been constructed. A heat exchanger is machined directly into the upper copper mounting block and is filled by a flexible, vacuum jacketed LN2 line that runs through a roof labyrinth to a phase separator on the roof of the 34-ID-A (FOE). The pressure in the phase separator is maintained only slightly above atmospheric, so the liquid nitrogen is gravity fed down the central tube of the triple-walled LN2 line, with exhaust gas returning in the intermediate, annular region of the same line. The phase separator is connected to the central APS LN2 supply.
Septum mask in 34-ID-B
The septum mask is responsible for dividing the reflected, pink beam from the white beam. It has a series of DI-cooled, inclined Glydcop faces to withstand all possible mis-steerings of the mirror. Our design was complete at the time of the PDR and was approved. It has been manufactured as designed. The septum mask is bolted directly to the L5-83, which is a newly designed component described below. There is no fine tolerance required in the positioning of the septum mask; the two masks can therefore be mounted on a single table for survey and alignment. This table also carries a diagnostic chamber with viewports that allow the face of the mask to be examined through a window in the front wall of 34-ID-B, as well as a ion pump and isolation valve for the first WBT.
Beryllium windows in 34-ID-B
Two standard W3-20 beryllium windows are used in the SOE. One is placed on the pink beam transport, just downstream of the septum mask, the other sits on the white beamline downstream of the modified L5-83 mask. These windows separate the vacuum systems of the two experiments from the ring vacuum. If two undulators are used, the white beam window will be subjected to a total power of 290W, over a 1mm(v) ´ 2mm(h) area. The pink beam will see a total power of approximately 186W, over a 1.4mm(v) ´ 2.8mm(h) area.
P9-30 (pink) in 34-ID-B
The P9-30 shutter was originally designed for use on Sector 2-ID. Space constraints there determined that the pump port be mounted on the side of the vacuum chamber containing the upstream shutter blade. The proximity of the white and pink beam transports made this configuration unworkable in Sector 34’s SOE. The vacuum configuration of the shutter chamber was therefore modified so that the pump hangs directly below the support table, similar to the orientation of the pump on the P9-40 shutter. For similar reasons, the DI water connection for the mask that sits between the two shutter blades has been moved to the outboard side of the shutter. No changes were made to the shutter block cooling or mechanical support.
K3-22 in 34-ID-B
The K3-22 collimator that shields the second white beam transport has a 6mm diameter aperture (reduced from the standard 12mm) and sits 44.1m from the source. The maximum excursion of the bremsstralung radiation at this point is 182mm(h)
´ 37mm(v), while the radius of the tungsten cylinder in the K3 is only 50mm. A lead block 91mm wide ´ 140mm high, will be placed behind the K3 on the outboard side as well as a 52mm ´ 140mm block on the inboard side to cover the remainder of the bremsstrahlung. The assembly will be covered with plexiglass and labeled as a configurational control item. Figure 4 shows a cross sectional schematic of the collimator and lead blocks with a projection of the maximum bremsstrahlung excursion.
P9-30 (white) in 34-ID-D
See P9-30 in 34-ID-B above.
Safety shutter in 34-ID-D.
In the PDR we had anticipated using a front-end S1 safety shutter in the TOE to allow safe access to the MFD hutch while beam is present in other part of the beamline. This S1 has now been replaced by a S3 shutter, which is also a standard component, but more compact. The maximum horizontal excursion of the bremsstrahlung rays is 16mm at 58m, where the shutter is positioned, making the extremely wide tungsten blocks used in the S1 unnecessary.
4. New component designs
1. Collars for First White Beam Transport between 34-ID-A and 34-ID-B
The first white beam transport will be supported by a slightly modified version of the standard U1-63 stand. The U1-63 stand was originally designed to hold shielded transports up to 6" in diameter, our transport requires 8" pipes. On the advice of Joseph Chang, the base plate has been enlarged for greater stability under the increased load. The vertical pipe clamps have been expanded to accept the larger pipe diameter, and the number of bolts used to secure the clamps to the carriage has been increased from three to five.
3. Modified L5-83 Mask in 34-ID-B
The modified L5-83 mask that protects the second white beam transport from excursions of the synchrotron beam is positioned at approximately 43.6m from the middle of the straight section. A cross-section of the assembled mask is shown in figure 5. The slopes of the tapered sides were calculated based upon the taper of the standard L5-83 that sits at 25m from the source in the differential pump unit (V1-90). The power density encountered by the standard L5-83 from a single undulator is 368W/mrad2. Since the power density in the beam at 44m is reduced to 121W/mrad2, for the single undulator case, the taper on our mask faces can be increased from 2° to 5° on the top and bottom faces, and from 3.7° to 10° on the sides without increasing the power density incident on the mask surface. This was the rough calculation presented in the PDR.
Since we now wish this component to be compatible with operation of the beamline with two undulator A’s in tandem, the calculation has to be considered more carefully. We repeat the full calculation for the component that we plan to use, described in figure 5, which has a 10° slope on the Glydcop side surfaces and a 5° slope on its upper and lower surfaces. Our calculation is a scaling from the DX version of the L5-83 which has a 3.7° slope on the Glydcop side surfaces and a 2° slope on its upper and lower surfaces. Of the two pairs of surfaces, it is the sides that present the large thermal load; the top and bottom surfaces are merely tapered to match the same overall length. The DX version of the L5-83 can operate safely at a distance of 25m from an undulator A with a gap of 8mm that generates 230kW/mrad2. Our version of the mask in figure 5, which operates at 44m from the source, can therefore withstand (44/25)2´ (sin3.7/sin10)´ 230kW/mrad2 on its side surfaces, which is 265kW/mrad2. The mask, and therefore the beamline, can therefore operate safely with a single undulator A, even with an 8mm gap. Since this number is not quite less than the 280kW/mrad2 produced by two undulator A’s at 11mm gap, we plan to restrict the operations with two undulators so that both gaps are never fully closed at the same time or that the steering of the beam through them is such that their beams are canted.
As an independent confirmation of the design parameters, we asked B. W. Riemer of LMES Engineering to carry out a finite element analysis using the P/THERMAL code of the heat flow in our version of the L5-83 mask, as described in Appendix B. He assumed illumination at 20.7W/mm2 of an infinite strip, 3.26mm wide, on the sides of the mask at and angle of 10° corresponding to the 230kW/mrad2 of a closed gap undulator A. Cooling was by a single water channel of 9.5mm diameter, 6mm behind the strip as used in our mask. The flow rate of 1.5m/s gave a film coefficient of 0.01132W/mm2/K, assuming an additional 50% effect of the meshes. The result was a "hot-spot" temperature of 442° C, which seems very safe.
6. Second White Beam Transport in 34-ID-C
The Second White Beam Transport (WBT) is a critical safety component that is unique to our tandem beamline configuration. Monochromatic beam transports passing through operational hutches are employed on other beamlines, such as MUCAT, without special provisions. White beam transports are widespread in isolated areas which do not experience heavy traffic. These do not have sophisticated alignment systems, nor armored support structures beyond a single leg every eight feet. We were informed that our WBT is different because:
i) it is smaller diameter, hence more deformable, and has a closer separation between wall and beam.
ii) it is in a heavily utilized hutch in the close vicinity of a massive diffractometer, whose detector arm could, in principle, collide with the WBT.
We have held several detailed discussions with the beamline design group, particularly Deming Shu, about this component. Our first proposal, based on thick wire clamps on a plastic base was considered to be insufficiently reliable, particularly against deformation of the lead shield surrounding the beam pipe and for constraining possible twisting motions.
We also had discussions with P. K. Job about the diameter of the pipe. He assured us that the 16mm ID WBT of our original design would provide sufficient shielding, provided it was covered with 12mm of lead. We have chosen to increase this ID to 30mm in order that the alignment is less critical. We also expect that the alignment of this configurational control item will not have to be verified so often.
A schematic of our second WBT is shown in figure 6. It consists of three similar sections connected with bellows. The pipe itself is 35mm ID, wrapped with 12mm of lead and a thin stainless steel cover. It is supported by this outside wall, which is not particularly rigid, so the load must be distributed over a large contact area. The pipe clamps are welded C-shell units with a close spacing to provide this. The three pipes are clamped to heavy welded sub-frames made from 6"
´ 4" box-beams. The sub-frames are then positioned on welded tables through kinematic mounts. The shear weight of these sub-frames ensures they will not be dislodged easily.The first step in the anticipated alignment procedure will be to straighten each pipe by means of shims between the C-shell clamps and the sub-frame. This will be achieved at the ±1mm level by sighting the center of a round plug which is passed through the length of the pipe. Three tool-ball fiducials on the sub-frame will then be measured relative to this center line, again at the ±1mm level. These will then be surveyed to the beam center when the sub-frames are installed in place. Periodic verification will then be possible without disassembly.
7. Pink beam stop in 34-ID-C
The photon stop for the pink beam will sit near the back wall of 34ID-C, approximately 54.5m from the source. The maximum total power it will experience, based on 280kW/mrad2 from two undulators and a 30% mirror reflectivity, is 98W. This power will be spread over a 1.8mm(h) ´ 1.9mm(v) spot size, with a power density of 28W/mm2. In order to reduce the power density on the copper face of the stop to an acceptable level of 10-12 W/mm2, the copper plate, shown in figure 7, will be inclined at an angle of 25° .
8. Safety Shutter in 34-ID-D
The PDR identified the safety shutter in the TOE (34ID-D), used to allow personnel access to the 34ID-E hutch while the others are in use, as an S1 front-end model. We have changed this to the smaller S3 shutter, which provides a duplicate thickness of 200mm of tungsten.
The S3 shutter is not modified from the description on the DX.
9. White beam stop in 34-ID-E
The photon stop for the white beam will sit near the back wall of 34ID-E, approximately 66.5m from the source. The maximum total power it will experience, based on 280kW/mrad2 from two undulators, is 289W. This power will be spread over a 1.5mm(h) ´ 3.1 mm(v) spot size, with a power density of 62W/mm2. In order to reduce the power density on the copper face of the stop to an acceptable level of 10-12 W/mm2, the copper plate, shown in figure 8, will be inclined at an angle of 10° . A lead bremsstrahlung stop sits directly behind the copper plate. The dimensions of this stop will be 125mm(h) ´ 125 mm(v) with a depth along the direction of the beam of 300mm.
5. Construction schedule, 2000
March/April Final draft plumbing specs.
April shutdown Install ID/Front End
End April Ben. Occ. For all Hutches
Early May Connect water/air mains (delayed to June)
Early June PSS validation (doors only, components bypassed)
June 5 34-ID-A Shielding Verification
Mid June Install FOE Mask/Collimator, M4 and K3
Tie M4 mask into PSS
Install 1st WBT between 34ID-A and 34ID-B
June 20 34-ID-B and C Shielding Verification
July Survey shutters + masks on floor
August PSS Validation (Shutters + Masks + Stops)
Survey 2nd WBT
2nd WBT Shielding Verification
September Preliminary operation
6. Ray tracings
The final ray tracings are shown in figures 9 and 10. A few components have moved since the PDR, but there is no change in the basic functioning. A brief summary of these shielding functions follows.
Collimators in the FOE (34-ID-A) reduce the Bremsstrahlung cone sufficiently that it can pass through the first WBT. Collimators in the SOE (34-ID-B) reduce the Bremsstrahlung cone further so that it can pass through the second WBT, which is located inside the CXD hutch (34-ID-C). The remaining Bremsstrahlung is stopped by a lead shield at the back of 34-ID-E.
Water-cooled apertures are used to keep all synchrotron radiation paths from reaching any of the Bremsstrahlung shields and to reduce power levels on the two photon shutters when they are closed. The front-end L5-83 protects the face of the M4-20 in 34-ID-A. This M4-20 protects the K3-22 in 34-ID-A and the first WBT. The septum mask in 34-ID-B protects the face of the L5-83 in 34-ID-B. This L5-83 protects the K3-22 in 34-ID-B and the second WBT. The pink-beam stop protects the shield wall in 34-ID-C. The white-beam stop protects the final Bremsstrahlung shield in 34-ID-E.
An updated summary of all optical elements, listing their positions along the beamline, apertures, length, etc. is included in tables 1 and 2.
|
Transverse dimensions of Bremsstrahlung and unfiltered Synchrotron Radiation (mm)
|
|||||
|
Optical Element |
Position |
Synchrotron |
Bremsstrahlung |
||
|
Horizontal |
Vertical |
Horizontal |
Vertical |
||
|
L5-83 |
25215 |
± 17.5 |
± 3.7 |
||
|
M4-20 |
26485 |
± 3.3 |
± 2.5 |
||
|
K3-22 |
26910 |
± 2.3 |
± 1.1 |
+75.2, -47.9 |
± 14.9 |
|
Lead Block 1 |
27148 |
+78.6 |
|||
|
Septum |
43238 |
± 18.7 |
± 4.2 |
||
|
L5-83 mod |
43511 |
± 18.9 |
± 4.2 |
||
|
K3-22 |
44135 |
± 0.6 |
± 1.1 |
+82.6, -31.6 |
± 18.3 |
|
Brick2 |
44403 |
+83.8 |
|||
|
2nd Trans. Pipe |
47136 |
f 2.0 in, f 4.5 out |
f 8.1 in, f 13.9 out |
||
|
Synch stop |
66000 |
± 3.8 |
± 3.6 |
||
|
Brem stop |
66464 |
-- |
-- |
f 21.5 |
|
Table 1. Synchrotron and Bremsstrahlung excursions at various optical components.
|
Mask and Shield Dimensions (mm)
|
||||||
|
Optical Element |
Length |
Aperture |
Outside Dimension |
|||
|
Horizontal |
Vertical |
Vertical |
Ring-side |
BM-side |
||
|
L5-83 |
275 |
± 20.05 in ± 2.25 out |
± 12.01 in ± 2.25 out |
± 53.3 |
53.3 |
53.3 |
|
M4-20
|
133.5 |
f 9.37 in f 2.0 out |
± 31.75 |
31.75 |
31.75 |
|
|
K3-22 |
198.4 |
f 6.0 |
± 49.5 |
49.5 |
49.5 |
|
|
Brick |
300 |
± 38 |
-- |
± 50 |
187.5 |
187.5 |
|
Septum |
70 |
+18.0,-20.0 |
± 49.1 |
± 58.7 |
174.2 |
22.6 |
|
L5-83 |
275 |
± 20.05 in ± 2.25 out |
± 12.01 in ± 2.25 out |
± 53.3 |
53.3 |
53.3 |
|
K3-22 |
198.4 |
f 6.0 |
± 49.5 |
49.5 |
49.5 |
|
|
Brick2 |
300 |
+38 |
-- |
± 50 |
-- |
123 |
|
2nd Trans. Pipe |
8400 |
f 16.0 |
-- |
-- |
-- |
|
|
Synch stop |
250 |
-- |
-- |
± 25 |
40 |
40 |
|
Brem stop |
300 |
-- |
-- |
± 75 |
75 |
75 |
Table 2. Optical Component sizes and positions.
Since some of the requirements were unclear from our written hutch specification (Appendix C) there were questions raised in the PDR response. Some of the requirements were also relaxed at construction time on the advice of P. K. Job. We are therefore providing a revised table of hutch wall thicknesses corresponding to the actual construction.
|
34-ID-A |
34-ID-B |
34-ID-C |
34-ID-D |
34-ID-E |
|
|
Upstream Wall |
NA |
19 |
19* |
19* |
19* |
|
Downstream Wall |
50 |
50 |
50 |
50 |
50 |
|
Side Walls |
19 |
19 |
19 |
19 |
19 |
|
Roof |
12 |
12 |
12 |
12 |
12 |
Table 3. Hutch wall lead thicknesses.
6.1 Intermediate Configurations
Ray tracings for the temporary shielding configurations that will be used during the hutch verification process are included in figures 11 through 13. The bremsstrahlung stop for commissioning 34-ID-A will be a lead pile with dimensions of 368mm (horizontal) ´ 152mm (vertical) ´ 300mm (see figure 11). The stop used to verify the B and C hutches must be 281mm (horizontal) ´ 155mm (vertical) ´ 300mm (see figure 12). The stop used to verify the D and E hutches must be 355mm (horizontal) ´ 176mm (vertical) ´ 300mm (see figure 13).
7. PSS Summary
There is no change of basic function since the PDR, but as a clarification we provide a complete description of the essential functions.
There are three logical sections to the access control of the five hutches:
• The three optics hutches 34-ID-A, 34-ID-B and 34-ID-D. All three must be secured before the front-end shutter is allowed to open.
• The CXD experimental hutch 34-ID-C. This must be secure before the pink-beam shutter (P9-30 in 34-ID-B) is allowed to open.
• The MFD experimental hutch 34-ID-E. This must be secure before the white-beam shutters (P9-30 and S3 in 34-ID-D) is allowed to open.
Here is a list of the actively interlocked components under PSS control. Each will be monitored by pressure and flow sensors on the DI water cooling circuit:
• M4-20 mask in 34-ID-A
• Septum Mask in 34-ID-B
• L5-83 mask in 34-ID-B
• P9-30 in 34-ID-B
• Pink beam stop in 34-ID-C
• P9-30 in 34-ID-D
• S3 in 34-ID-D
• White beam stop in 34-ID-E
The positions of the following shielding components are under configurational control:
• M4-20 in 34-ID-A
• K3-22 in 34-ID-A
• Lead blocks behind K3-22 in 34-ID-A
• First White Beam Transport (WBT) between 34-ID-A and 34-ID-B
• Septum mask in 34-ID-B
• L5-83 in 34-ID-B
• K3-22 in 34-ID-B
• Lead blocks behind K3-22 in 34-ID-B
• P9-30 in 34-ID-B
• Second WBT passing through 34-ID-C
• Pink beam stop in 34-ID-C
• P9-30 in 34-ID-D
• S3 in 34-ID-D
• White beam stop in 34-ID-E
• Bremsstrahlung stop in 34-ID-E
8. EPS Summary
We will include the following components in the Equipment Protection System (EPS) interlock. Any one of the checks listed below will lead to a closing of the front-end safety shutter. The EPS will be constructed from Koyo 205 and 405 programmed logic controllers (PLC) with direct relay contact interconnections between the segments. The status will be accessible to users or read out via an ethernet link. The design is modeled on that of sector 33-ID.
The EPS PLC itself will be very simple. It will accept only relay contacts on its input and pass a single relay output back to the front end. All other communications will be through a read-only ethernet connection. We will also log water flow rates, temperatures and pump pressures with a logging linux computer (called "alarm") that also serves as a boot source for the epics/VME controllers on the beamline. This logging computer will be able only to read the status of the EPS PLC, but is otherwise an independent local function.
Generic descriptions of the various kinds of relay inputs to the EPS PLC are:
• standard switch contacts on VAT-brand gate valves. The closed switch contact is provided to the EPS only when the gate valve is fully open. A second switch is closed when the valve is sealed; this contact will be monitored as a vacuum interlock.
• programmable threshold relay outputs from Physical-Electronics Digitel MPC ion-pump controllers. We are using dual-pump supplies each with four independent pressure level sensors. A threshold in the range of 10- 7 Torr will be programmed on each pump. The switch contact will only close when both the pressure is below the threshold and the pump is energized.
• threshold sensors on Omega-brand model i/8 thermocouple readouts, one per thermocouple. One thermocouple will be used on the sacrificial molybdenum mask in front of the mirror; its relay contact will open if the temperature rises above 50° C, indicating that the mirror is missteered and that beam is hitting the face. Because of the small thermal mass, this thermocouple will respond quickly to this undesirable condition. The second thermocouple will be mounted on the LN2 cooling block of the mirror; its relay contact will open if the temperature rises above - 100° C, indicating that the supply of LN2 is interrupted or running out.
• Proteus-brand water flow sensors, with preset threshold integral to the controller. A relay contact monitored by the EPS will open if the flow rate falls below a preset value determined by a potentiometer on the controller. The flow itself will be monitored (by "alarm") by counting output pulses with a F4-8MPI module incorporated in the Koyo 405 PLC.
Cabling between the hutches will consist of shielded DB25 cables for the EPS relay contacts, shielded 4C/22AWG and 8C/22AWG cables for the Proteus pulses. Shielded DB9 cables will be used for the RS232 interrogation of the pump power supplies and temperature controllers. Functions in 34-ID-A will be read through the EPICS/VME system in 34-ID-A. Functions in 34-ID-B will be read through the EPICS/VME system in 34-ID-C. Functions in 34-ID-D will be read through the EPICS/VME system in 34-ID-E.
Here is a full list of the EPS controls in 34-ID-A:
4 in-line gate valve position sensors: after M4-20, before and after mirror, at end of WBT
3 ion-pump power supplies: on L5-90, on mirror, on WBT
1 water flow sensor on: L5-90 slits
2 thermal sensors on mirror cooling: Mo mask and body
Here is a full list of the EPS controls in 34-ID-B:
2 in-line gate valve position sensors: before septum and start of WBT_2
4 ion-pump power supplies: on septum mask, after L5-83 on mirror, on WBT_2, on P9-30
3 water flow sensors on: Beryllium windows (2), on CXD monochromator (when installed)
Here is a full list of the EPS controls in 34-ID-D:
2 in-line gate valve position sensors: before and after MFD monochromator
4 ion-pump power supplies: on WBT_2, on S3, on P9-30, on MFD monochromator
1 water flow sensor on: on MFD monochromator.