Shield may be ready in late February but requires possible redesign of corner. Details will be available week of Feb 8. In the discussions of any redesign, it would be desirable to have the manifold corner right next to the edge of the magnet moved inward slightly. Moving it outward any distance is a potentially serious problem. Shield would be at BNL the end of the first week of March at the earliest. There would be a big advantage to have it at BNL in time for Marek Stodulski to check installation if the tunnel is open. Ideally, the shield supports will be discussed in March with possibly some fabrication work at BNL or MIT (not by Krakow people) prior to April. We will try to avoid having supports glued or attached to the thermal shield except possibly glued to the thicker manifold sections.

Following Bernie Wadsworth's request, the enclosure will be electrically insulated from the magnet yoke.

We need to think about installation for top and bottom windows. What must be changed to install or remove them? The extension for the octagon in the top window is only 10 cm high so it will fit through the magnet gap easily. The extension at the +Z side of the top window is larger so this window can only be installed from the +Z side. The bottom window in the preliminary design could not be installed because it had extensions on both sides that were larger than the magnet gap. It was decided to keep the V-shaped extension and small shelf on the -Z edge as part of the large window. This will need to be installed from the -Z side. The bottom of the V-shaped extension clears the rails on the octagon and spectrometer small blocks so it is OK. The +Z side of the bottom window will need to be changed so that no part extends more than 10 cm below the flat window surface.

Skeleton - Light rectangular frame providing window support only with minimal tension.

Bottom window - 1/2 mm Al resting on thermal shield (with thin insulation in between). Supports for thermal shield can be used to provide extra support for window. Bernie Wadsworth will be asked for suggestions on the insulating material.

Top window - 1/2 mm Al supported by rectangular frame. Additional supports will be provided from the pole plate above along the beam line at the raised section for the octagon and also farther along the beam line possibly from a strap or strut in the gap between the thermal shields. An attempt will be made to combine the supports for the thermal shield at the manifold and the supports of the window around the edges. Finally, there will be an insert in the hole in the center of the magnet to support the window in the area of the spectrometer.

Deflection of the top window of 2-3 mm is acceptable but more deflection is a problem due to a) Electronics boards sticking out the top of the octagon and b) Survey markers on the top of the spectrometer cooling frames. GSFS will check survey marker clearance.

Checked for shadowing of TOF due to corner of the enclosure window. This is not a problem. Checked for shadowing of the forward TOF section due to the +Z extension of the enclosure. It is outside this section so there is no shadowing problem. The trigger counters are inside the corners so also not shadowed.

GSFS provided manifold box details to show where vertical struts of the skeleton are blocked.

Question: Do the window support frame and the thermal shields interfere? Need to wait for shield to be delivered to check. Can be easily fixed if a problem is found. Thick part of skeleton will be cut back 1 cm from location of thermal shield corner.

Question: Do support frame and manifold covers interfere? These are probably OK. Any overlap must be small. The manifold covers can be easily modified to lower the top a few mm if necessary.

Support frame corner reinforcement on the +Z side is a problem. It is likely that some attachments to the magnet module covers will be made to help provide stability. These added supports will be designed and built in place at BNL.

Side windows - At +/-X, thin material (aluminized mylar? double for opaqueness?) should be used everywhere in the region of about +/-8cm from the beam height (more in regions far from the IP, or where possible). Vertical struts passing through beam height should be avoided unless absolutely necessary. Shadowing of TOF, rings, and trigger counters needs to be checked for any proposed supports. At -Z, thin material is required only where the ring and trigger counters are shadowed.

Extension at +Z - The height of this extension will be raised slightly to allow more clearance for the ring counter inside the magnet. The vertical supports through the beam height at the +Z (and at -Z next to the magnet?) side of this box will be eliminated. This box will have three windows. On the +Z side of the box, the window will be supported by a thin frame (1x1cm square Al. tube 1mm thick or smaller) around the outside. The flange for the connection to the beam pipe will be larger than in the latest design so that it overlaps this frame at the top. There will be a horizontal support at the bottom of the flange, but only if necessary. This window at +Z will be thin (mylar or very thin Al foil). The horizontal support struts on the +Z side of this extension will be moved as low as possible to improve access to the ring counter and spectrometer fixed supports inside. The windows on the sides at +/-X will not have a supporting frame. They will use the frame for the +Z window to provide support at the corners. These side windows can be 1/2mm Al but there should exist the possibility of replacing with thinner material in the future. Currently, these +/-X windows are designed to be two pieces, one on a structure sitting on the concrete block and one removable piece. It is suggested to make the entire +/-X side windows as one full-height removable piece. The bottom part of this extension should be removable.

Octagon electronics may be moved again. There is a problem of interference with the spectrometer window when the detector is moved out.

Assembly question: How do we open and close the joint between the enclosure covers attached to the spectrometer and octagon? Access is very restricted in this area. Velcro? There is a similar question/problem with the bottom seam of the section that opens with the spectrometer and octagon.

Flanges for the beam line cover at both +/-Z have been redesigned to have larger radius. For the connection to the beam pipe, it is acceptable to have a simple cone design which must be destroyed and replaced each time it is removed.

Most notes sent in mail message (2 identical carts, outer cart sits on 3 floor plates, bottom of cart parallel to floor, need two different base plates, rail systems, and cart brackets for mounting two walls inside the magnet, cost to be negotiated, same design but not same cart for two sides of magnet, wheels are retractable.)

Cart clearance to extend beyond magnet manifold covers was increased by 1 cm. GSFS will recheck. It was marginal before, should be fine now.

Cart will sit on 3 floor pads, 2 with dowel pins. This allows the 2nd cart to roll in and out without hitting floor pads. If desired, small posts with shims could be added under the wheel struts on the side with one pad (these posts will be made at BNL, not by Krakow).

Jurek Halik proposed a clever scheme to insure the proper orientation of the TOF on the carts when used on either side of the beam. The cart normally used outside the magnet will have the clearance gap for magnet manifolds on the side away from the magnet.

Jurek Halik and Marek Stodulski will supply in advance of their trips a list of hardware, tools, and machining resources (drill-press, milling, etc.) required for their work at BNL. It is understood that the stainless steel welding required on the water cooling system will only be for repairs or modifications and may be done by BNL people. If this capability is required for fabrication, Krakow will supply details in advance.

Wojciech Bogucki suggests that a compressor with regenerative drier will require a pre-cooler drying system to get air to about 20% humidity. The regenerative drier is used only at the end of the system to get to very dry air. According to a recent e-mail, this is not true of the system currently in use at BNL with heaterless regenerative driers. GSFS will inquire in more detail about the system in use at BNL and send the information to Krakow before 19-Feb

WB has proposed a modification of the system 6 initially proposed, adding an additional drying stage. This change is necessary due to the new request from GSFS to have a system capable of going down to ~0% humidity. With such a system, one could turn off the final drying stage if humidities around 20% were requested and only turn the drier on if lower humidities were required. The new recommendation (fig 6) differs from the earlier version (fig 5) due to the availability of commercial units for refrigerated drying.

In the design of the water cooling system, the inlet and outlet water supply pipes should be at a level of 0.5m or less to avoid the possibility of extra pressure in the thermal shield. A final discussion of the arrangement of stainless steel pipes versus pipes of other materials (not copper) or hoses on the magnet needs to be arranged. GSFS does not want pipes on the floor on the inner side of the tunnel since this is the primary access route for equipment. Also, he believes that a location next to the inner edge of the magnet will obstruct access to other detector components.

As a result, the water cooling system should be located on the outer wall. The area between the exhaust vents next to the magnet is too small. The system will be located outside the vents. GSFS has not yet decided if it should be at +Z or -Z. WB said that 10m of pipe from cooling system to magnet is acceptable, although a shorter distance would be preferable.

The current proposal for the air cooling system in along the inner wall at the +Z side. The air hoses would follow the water-cooled bus path to the detectors.

WB would prefer to have the two cooling systems close together because of control signal cables that connect them. GSFS will consider this possibility if space is available. The air system would be moved since the water system is constrained as described above.

Power requirements of both cooling systems were reconfirmed. No changes from e-mail of 18-Sep but numbers for modified air system will need to be provided. Plug types for 208 modules need to be checked.

The cantilever arm will not be moved or redesigned. The cables for one FEC crate donít hit the arm. The cables for the other crate have 4+ inches of clearance except for the last slot. Since there are only 29 cables (capacity of 32 in crate), the last slot can have fewer cables which can have a special routing.

Marek will investigate making these added pieces less than 70 mm in height. If this restriction is unacceptable, the FEC fan will need to be put on top of the crate. Having the fan in between the reinforcement plates does not appear to be possible.

The sizes of all concrete blocks were reconfirmed. The height of the top frame will be

557 mm for the ring counter stands and the L frame at +Z. For the spectrometer/octagon L frames at -Z, the height will be 552 mm (a change +2mm from previous). The arrangement of parts was discussed and approved. The blocks will sit directly on the floor. A metal plate (proposed thickness ~3/4 inch) will mount onto the concrete block with 6-8 large bolts. Krakow will have the opportunity to approve the metal plate design. These mount points will have (removable) vibration isolation. The L frames will bolt to the metal plates. The holes in the metal plate for this mounting will be marked, drilled, and tapped in place after alignment of the L frames. Krakow will provide a drawing of the additional L frame for the spectrometer fixed supports and the ring counter. Krakow will provide shims or spacers to adjust the height of ring counters where necessary.

All flex cables will be custom made to length. There will be no spare cables, just spare material to make cables. There are no restrictions on the number of different lengths of cables allowed.

The flex cables will be held by hooks along the cooling frame and then finally by a bar attached to the cooling water tubes at the cooling frame exit point. The next strain relief will be in the transition region. This will consist of three combs (in two levels, six bars total, to be designed and fabricated by the mechanical structure group at Krakow) with slots to hold the cables. The connections from internal to external cables will be between the two combs (two rows of connectors). The next strain relief will be at the passage through the detector enclosure (to be designed by the detector enclosure group at Krakow). Bernie Wadsworth is responsible for design and fabrication of the strain relief between the detector enclosure and the FEC connectors. Some flex cables from upper electronics hybrids need to connect to FECís in the lower crate and vice versa due to common grounding considerations. These transitions up and down will occur in the region between the combs and the FEC, i.e. only in the exterior cable route.

A new release of the 3D drawings will be prepared by the time of Marek Stodulskiís visit including more up-to-date estimates of the sizes of the water and air cooling systems and the water manifolds (including distribution boxes and pipes on the magnet). If newer versions of parts of the TOF or detector enclosure are available, they should also be included.

Assuming that comments are received soon, all of the jigs for mounting the modules on the cooling frames will be fabricated during the Feb/Mar trip to MIT. The cooling frame sub-plates (a full set of 8 pieces) will be fabricated. These plates are rigid and can be carried without a special handle but will need covers. Also, they will not need a special stand, but some sort of turntable will be provided. Finally, the subplate carrying jig and special support stand needed for mounting cooling frames on the spectrometer small plate will be designed by Mid-March and fabricated by April/May. The carrying jig for transferring the full small plate to RHIC will be finished by June. The schedule for other hardware (cable hooks, etc???) will be discussed during the Feb visit.

The extending corner of the spectrometer small plate can be modified to leave more clearance for octagon cables. This will be done at BNL in April. Bernie, Gerrit and Heinz will be consulted about parts of the module cover extending slightly beyond the edge of the plate.

Needs to be provided, dates for final cart design (end of Feb?) and delivery of various parts (carts by end of April, top structure by late March, rail system to be fabricated at Rochester).

Skeleton will be at BNL in time for the visit in late Feb/early March. Need dates for remaining parts (ideally everything by end of April).

Arrangements need to be made to provide transportation for Krakow people at BNL. The next trips are confirmed as 14-Feb -> 14-Mar (3 people to MIT) and 23-Feb to 6-Mar (2 people). Dorm reservations have been made but the MIT apartment will be used if space is available. Arrival date for the following trip is confirmed to be 6-Apr (5 people). Marek Stodulski will depart around 6-May and the remaining people will depart around 6-June. Detector enclosure travel in May needs to be confirmed.

It is acceptable for Marek Stodulski and others arriving in mid-February to delay going to BNL until later in February to be trained with the detector enclosure group. Bolek will arrange for the training of technicians with poor English skills.