DUKHEP03-04-28
Barrel Support Structure Report
Doug Benjamin, Jack Fowler and Seog Oh
Department of Physics
DukeUniversity
Durham, NC, 27708
April 28, 2003
Introduction
The following is a summary of work to be completed for the Barrel Support Structure at CERN. This is based on meetings as well as current schedules, from a trip to CERN late March ’03 by Doug Benjamin and Jack Fowler. This report summarizes the discussions of work that is to be completed by personnel at DukeUniversity. Many of the tasks are well defined and have a schedule based on delivery of components to CERN. However, some of the tasks are still in the R&D stage and are not as clear. Also, there are estimations of time in which each of the tasks are schedule to be completed. These times are based on current delivery dates and also estimate the amount of time for some of the CERN work groups to respond. These times are based on experiences of using similar facilities at both Duke University and FNAL. We are unsure if the same estimations are valid at CERN due to workload and scheduling.
The BSS includes inner cylinder (one piece), outer cylinder (two pieces) and the end frames (two pieces) as well as the assembly and alignment of these parts. The completed BSS will be in the SR building at CERN and ready to accept the barrel modules.
Inner cylinder
This part will be delivered June 30, 2003 from Technologiya. The assumption is that this will be delivered machined complete with all necessary holes. We need to get a copy of the final drawings to review the specifications and a list of the critical dimensions. From this list of critical dimensions, we will determine the exact measurements that need to be taken.
Based on conversations with Andrea Catanicco and Neil Dixon at CERN, the major concerns are distance around the circumference, roundness and the amount of deflection along the longitudinal surface while supporting the ends. Measuring the distance around the circumference should be straight forward, but this may change based on the accuracy needed. The drawing will answer this issue.
The roundness cannot be measured without supporting the ends. Like the barrel module shells, the part conforms to the shape in which the ends are held. So in order to perform this measurement, some type of end cap or ring will need to be fabricated to support the ends of the cylinder. With the assistance of designers/draftsmen at CERN, these supports will be designed and the drawings will be forwarded to the machine shop at CERN for fabrication. The CERN metrology group will qualify these inspection fixtures. When the inner cylinder arrives, it will be mounted on the inspection fixture and measured by CERN metrology group.
Time required – 10 days - Approximately half of this time is required before the parts are delivered in order to have the fixtures designed, fabricated and certified. This could be done remotely via email or video conference. One trip in late May ’03 would help facilitate the design and fabrication of the inspection fixtures, but is not necessary. This trip would involve only one Duke Person. Travel to CERN will be required for the part measurements and data review. This second trip would involve two Duke Persons, but can be done concurrently with other trips. This travel would be done in July ’03.
Resources
Initial design concepts for inspection fixture - J. Fowler, D. Benjamin, N. Dixon
Discussions with CERN metrology – N. Dixon, J. Fowler
Final design and drawings – CERN designer, J. Fowler
Machining of fixtures – CERN machine shop, J. Fowler, N. Dixon
Certification of fixtures – CERN metrology, J. Fowler, D.Benjamin,N. Dixon
Certification of Inner Cylinder – CERN metrology, A. Catanicco, J. Fowler, D. Benjamin, N. Dixon
Outer Cylinder
These two parts will be delivered June 30, 2003 from Technologiya. The measurements are similar to the inner cylinder. However, the outer cylinder is a “clam shell” design made of two pieces. It is unclear if the two halves will need to be assembled together for inspection or they can be inspected individually. It is also unclear if the two halves can be assembled together or if the end frames are what will hold them together. These drawings need to be reviewed and some discussions need to occur before a specific plan for these parts can be made.
Time frame – 13 days – Approximately half of this time is required before the parts are delivered in order discuss the part design and function and to have the fixtures designed, fabricated and qualified. This could be done remotely via email or video conference. One trip in late May ’03 would help facilitate the design and fabrication of the inspection fixtures, but is not necessary. This trip would involve only one Duke Person. Travel to CERN will be required for the part measurements and data review. This second trip would involve two Duke Persons, but can be done concurrently with other trips. This travel would be done in July ’03.
Resources
Initial discussions of part functionality and design - J. Fowler, D. Benjamin, A. Catanicco, N. Dixon
Initial design concepts for inspection fixture - J. Fowler, D. Benjamin, N. Dixon
Discussions with CERN metrology – N. Dixon, J. Fowler
Final design and drawings – CERN designer, J. Fowler
Machining of fixtures – CERN machine shop, J. Fowler, N. Dixon
Certification of fixtures – CERN metrology, J. Fowler, D.Benjamin,N. Dixon
Certification of Outer Cylinder Pieces – CERN metrology, A. Catanicco, J. Fowler, D. Benjamin, N. Dixon
BSS Assembly Rig – Procurement and financial issues
The BSS assembly rig is being designed and the parts fabricated at RAL in the UK. Based on conversations with Andrea Catanicco, the design for these parts is very near complete. RAL is responsible for ordering the parts after design and having them delivered to CERN. The schedule is for the parts to be at CERN by the end of June ’03. However, it is unclear who has the financial responsibility for this. This needs to be worked out between RAL and CERN.
Time frame – Minimal – We should be able to handle this through conversations with CERN.
Resources
Discussions about financial issues – A. Catanicco, J. Fowler
Discussions about delivery – J. Fowler, A. Catanicco
BSS Assembly Rig – Assembly Rig Structure
Once all parts are received at CERN, they will need to be assembled. It is not certain exactly where this assembly will take place at CERN, but there are two places available. The assembly of the parts will require at least two people and will take approximately one week. Assembly and attachment of the rails is unknown at this time because all of the design is not complete. This is mainly in the fine adjustment mechanism. This had not been developed as of the March ’03 visit. It was discussed, that Duke personnel would be needed to help design this portion of the Assembly Rig Structure. This could take significant time working with the CERN designers and fabrication shops. The fabrication of this mechanism will be done at CERN.
There were also discussions about some permanently mounted reference points or spheres to use for the alignment of the assembly rig structure. These features are not finalized and will need some design time. This will also be done at CERN.
Once the Assembly Rig Structure and the rails have been assembled, the entire assembly must be aligned and qualified. This will be done in coordination with the CERN surveying group. This needs to be done in the place that the BSS will be assembled and attached to minimize the changes to the assembly rig during transport. It is our current understanding that the assembly rig structure will be assembled in Building 154 in the wheel assembly room and then moved to the SR building for alignment.
Time frame – 18 days – It will take 10 days to assemble the assembly rig structure and rails. This includes a rough alignment done by the TRT group. We will then have the CERN surveying group come in for the final alignment. This will take approximately one week. During most of this time, two Duke Persons would need to be available at CERN. The above may not include work time to make the rails adjustable as this design is not yet complete and all of the details not known at this time.
Resources
Design and fabrication of Assembly Rig Structure – A. Catanicco, RAL
Assembly of the structure – J. Fowler, D. Benjamin, CERN engineering student
Concept design of rail adjustment and alignment features – A. Catanicco, J. Fowler, D. Benjamin,N. Dixon
Detailed design and drawings of rail adjustment and alignment features – CERN Designer, J. Fowler, N. Dixon
Fabrication of rail adjustment parts and alignment features – CERN machine shop, N. Dixon, J. Fowler
Assembly of rail adjustment parts and alignment features – J. Fowler, D. Benjamin, CERN engineering student
Alignment of assembly rig structure - CERN surveying group, N. Dixon, J. Fowler, D. Benjamin
Analysis of data – A. Catanicco, J. Fowler, D. Benjamin
BSS structure – End frames
The end frames will be delivered to CERN in November ’03. These parts will be qualified by the manufacturer, and will be certified by John Callahan at the manufacturer. The CERN metrology group will also certify these parts.
While at CERN in March ’03, we discussed a measurement scheme with the CERN metrology group to certify the parts. We have a concept for the fixtures required for this. A proposal will be submitted to get approval to proceed on this certification. Once we receive approval, the fixtures will be detailed and fabricated by CERN. The design and fabrication of this fixture will be used as a reference for the time needed to get parts processed at CERN, since we have no experience with this. The CERN metrology group will verify the fixture after fabrication. We will then use the 1/8 sector of the space frame at CERN to qualify the measurement routine for the end frame. Very good measurement data exists for this 1/8 sector and we will compare the new data with this. Once the end frames arrive at CERN, we will inspect and qualify them using these fixtures.
The end frames also need to have some holes added for the copper plugs used in the faraday shielding scheme. These will have to be specified and added. It is our assumption that the placement is not extremely critical and the holes will be added by hand. If this is not correct, additional time needs to be added for proper machining.
Time frame – 24 days – The design of the fixtures and verification of the measurement routine with the 1/8 sector will take approximately 10 days. The design of the fixture will be done via email and conversations. The verification of the measurement routine will be doneduring a trip in June ’03. It will take approximately 7 days to do the measurement and evaluate the data for each of the end frames. This will involve another trip to CERN for the measurement once the end frames are received.
Resources
Approval of measurement scheme – J. Fowler, A. Catanicco
Initial design concepts- J. Fowler, D. Benjamin, N. Dixon
Discussions with CERN metrology – N. Dixon, J. Fowler
Final design and drawings – CERN designer, J. Fowler, N. Dixon
Machining of fixtures – CERN machine shop, J. Fowler, N. Dixon
Certification of fixtures – CERN metrology, J. Fowler, D.Benjamin, N. Dixon
Certification of measurement method –J. Fowler,CERN metrology, D.Benjamin, A. Catanicco, N. Dixon
Certification of end frames – A. Catanicco,J. Fowler, CERN metrology, D. Benjamin, N. Dixon
BSS Structure – Assemble, align and bond BSS spool on Assembly Rig
Once all of the parts and tooling have arrived and been certified at CERN, we will be able to assemble the BSS spool on the assembly rig. After assembled on the assembly rig, the TRT group will do a rough alignment using photometry. There are several concepts for this alignment but this has not been finalized. A detailed proposal must be completed and approved. This must be done by CERN personnel. The alignment needs to be done in the SR building in the area where the barrel integration will occur. We visited the SR building in March ’03 and are very confident that the building will be available when needed.
Time frame – 20 days – It will take approximately 5 days to mount the end frames and the inner cylinder on the barrel assembly rig. This includes time to move the structure over to the SR building and position it on the supported concrete pads there. It will take another 5 days to get the assembly aligned roughly. We will then allow the CERN surveying group to do the final adjustments and alignment. This will take several iterations and each iteration is expected to take at least 3 days. This includes taking the measurements and interpreting the data. It is assumed that at this time Duke would have a permanent presence at CERN by at least one person. Most of this work will require at least two Duke Persons to be present.
Resources
Develop measurement scheme – A. Catanicco,J. Fowler, D. Benjamin, N. Dixon
Assembly of the BSS spool – J. Fowler, D. Benjamin, N. Dixon
Rough alignment of BSS spool – J. Fowler, D. Benjamin, N. Dixon
Final alignment of BSS spool – CERN metrology, A. Catanicco,J. Fowler, D. Benjamin, N. Dixon
Bonding of BSS spool – N. Dixon, J. Fowler, D. Benjamin
BSS structure – Install Faraday Shielding
This includes mounting of faraday shield foils on end-frames, inner and outer cylinders.
Prior to the mounting of the faraday shield we need to finalize a few details. These include: 1) design and fabricate attachment between shield foils and end-frames and the end-frames and the cylinders, 2) study various schemes (with help of CERN electronics group) for soldering copper tape together, 3) determine assembly sequence of faraday shield.
We must answer the question which side of the outer cylinder halves is the shield foil placed and attachment scheme between the outer cylinder faraday shield and end frames. We will need help from the CERN designers to design and the CERN machine shops fabricate the electrical connections between the faraday shields and cylinders, end frames. We also have to agree on the locations of the connections. Until the final assembly details have been worked out, it is very hard to determine how much time it will take. We will use the shielding of the 1/8th sectors that will be used for the beam test to better approximate the time needed.
The application of the copper tape on the end frames is estimated to take at least two weeks per end frame for two people. We will have a better approximation for this after the 1/8th sectors have been completed for the beam test. This could take a significant amount of time due to the soldering of the copper tape. Until some testing on application of the polyimide-copper on a cylinder has been done at Duke, it is impossible to accurately estimate the time required, but I would expect that application should take at least 7-10 days for two people. If the cylinders come in before the end frames, we should be able to add the faraday shield ahead of the attachment of the cylinder to the end frame. Some travel to CERN is required to work with the designers, engineers and physicists to finalize the plans and get the required drawings made.
Time frame – 20 days – This time will be split equally between covering the cylinders and the end frames. This will require two Duke Persons in order to get the assemblies done in the time allowed. On an earlier trip we will finalize all of the design and assembly details with CERN personnel.
Resources
Finalizing design and assembly details – A. Catanicco, D. Benjamin, J. Fowler, A. Romaniouk
Attaching faraday shield to inner and outer cylinders – D. Benjamin, J. Fowler
Attaching faraday shield to end frames – D. Benjamin, J. Fowler
Conclusions
From the above summary, there are many things yet to be completed in order for the BSS to be completed and ready to accept barrel modules early in 2004. It was very clear in the meetings and discussions during the trip of March ’03 that CERN does not have the resources to complete the above tasks in the time required. The most significant are the final alignment scheme and the fine adjustment of the assembly rig structure. Each of these may take as much as a month to finalize. There is also the risk of delay in the delivery of the parts to CERN.
From the current time estimates and schedules, Duke personnel would need to have some presence at CERN beginning in June ’03. This would be to coordinate the verification of parts to be received. This is estimated to be 1 to 2 weeks per month. Many of the tasks would require two persons from Duke or additional support from CERN that may not be available. If planned appropriately, many of the trips could be scheduled to handle multiple tasks, but at least one trip per month should be expected. A greater presence would not be required until late summer (Sept. or Oct.) if the schemes for alignment and the shielding are approved. Work in the October and November time frame will be hectic and two people should be available at most times in order to complete the assembly and bonding of the spool.