Difference between revisions of "Tagger Engineering Design"

Revision as of 11:14, 25 April 2007

• Telephone meeting April 3, 2007 [Elke's notes]

  Sergey will be at Jefferson lab 30.04-07 - 01.05.07, we will have a meeting on April 30th with Franz coming to JLAB and Richard and Yang joining by video. Sergey will provide electronic versions of the drawing before this meeting to allow all people enough time to look to them and make remarks.

  In general the drawing follow the design from Jim Kellie and G. Yang. Special care should be taken to avoid stress on the vacuum chamber and o-rings. Franz will provide a list of hot topics on the design discussed in the past. Richard will provide Sergey where to find all the relevant information on the wiki. We will have a tagger-email list, which will have the list of people above pre-registered please tell your students or postdocs or .. to register so all the information is archived and all people are always informed.

• Discussion and questions regarding the Serpukov tagger design drawings
  • Franz Klein: The design effort should address the following areas of concern.
    1. Field and trajectory changes due to small misalignment of the magnets: this was answered in detail by Yang's simulation.
    2. Stress on vacuum chamber with 2 big magnets attached (relative motion of energized magnets and evacuated chamber).
    3. Sealing the large vacuum chamber at the contact with the magnets: large o-rings.
  • Yang Guangliang: About the drawings provided by the IHEP group, I found the following.
    1. In general, these drawings are based on our two identical magnet tagged design; the layout of the tagger has not been changed.
    2. Some of detailed things have been changed, they are:
       1. The number of brackets which are used to compress the O-ring and also to counteract the vacuum force has been reduced to half of the original number. The way to attaching this bracket to the pole shoes has been modified.
       2. The brackets used to support the coils have been redesigned.
       3. The vacuum chamber design has been modified slightly. A long metal strip was welded to those vacuum chamber edges which are around the pole stem, and are used to attach the O-ring compressing brackets to the vacuum chamber surface. At the same time, the pole shoe profiles have also been changed accordingly to accommodate the modified vacuum chamber.
       4. The O-ring groves were made on the vacuum chamber. Previously, we used a long strip of metal attached to the pole shoes lips to act as the O-ring groves.
       5. There is a detailed design about how to bolt the yoke and pole shoes together.
       6. There is a detailed design for the quadrupole magnet and stands.
       7. The brackets used to support the vacuum chamber have been modified.
       8. The thin window has been modified.
       9. The hole through the return yoke of the second magnet which is used to accommodate the photon pipe is not in the correct position and direction.
    3. There are several questions that I want to ask. They are:
       1. Have they done any stress analysis for the whole magnet to determine the location, size and the number of the bolts which are used to hold the magnet together? And what kind of method can be used to control the magnet deformation within limit when the magnet is operating at 1.5 T?
       2. Have they ever done any stress calculation for the vacuum chamber to determine how to support it?
       3. Have they done any stress analysis on the brackets to see if the brackets are strong enough? How many brackets are needed? From my point of view, I think the number of brackets used to compress O-ring is too small, and the number of brackets which are used to support the coil is too large.
  • Franz Klein: I've seen a largely reduced number of brackets and only minor changes in the vacuum chamber around the pole stems but I couldn't figure out how it can be insured that the o-rings stay in place when heavy pole shoes are placed on top.
    1. I'd like to see an explanation how the system is put together.
    2. I want to see what FEA or other stress analysis has been done on the new design.
    3. I will make a list of issues that were addressed w.r.t. Jim's and your design as well as questions about the IHEP design changes.