24 March 1995 To: Distribution: From: Stan Ecklund Subject: "IR +- 1m Engineering" Meeting Notes 24 March 1995 Martin showed the latest B1 layout with the vertex detector drawing included. He reduced the outer diameter of some blocks to relieve the interference with the vertex cone, and added a block closest to the IP to compensate. This new block has an interference with the vertex chamber. Roy will try to modify the SVD to remove the interference. Stan showed the calculated integral BL and beam orbits with the new proposed block geometry compared to the previous. The same parasitic crossing separation of 3.5 mm is obtained, but the integral BL is slightly lower (1.5%) which reduces the separation at Q2. We would like to recover the same BL to not reduce the Q2 septum; even increase it if possible. The B1 field calculation uses a residual field of 1.05 T. (Catalog value is a range 1.02 to 1.09 for ShinEtsu R26HS material) No allowance is put in for block assembly tolerances or azimuthal inefficiency; i.e. permanent magnet blocks touch their neighbors with no space between. Presently there is no room for trim coils for B1 so it must be built to tight tolerances. How does one fine tune the assembly of B1 to get the design field? Some of the block inner radii could be reduced, increasing the B1 field if we went to a 4 tip mask. Mike will investigate this. We should also try to minimize the number of different size/shape blocks in order to keep costs down. Time scale requires that the Silicon order must go out in June. A prototype is expected by late April. Roy's lab is starting to construct a model of the B1 now. The machine abort radiation detectors need to be added to the drawing. Roy will get dimensions from Pat Burchat. We discussed the possibility of moving the IP longitudinally, toward the upstream HER beam direction by 5 to 10 mm. This makes it easier to fit the forward 300 mr cone into the B1 geometry. The down side is complications to the machine; two which came to mind were the decrease in parasitic crossing distance on one side, and changes in quad focusing to move the beta waist. This is not the baseline but we will consider its feasibility. Action Items: 1. Add mask cooling channels to drawing. [Martin] 2. Investigate B1 temperature stabilization. [John H.] 3. Try to fix interference of SVD with first block [Roy K] 4. Show location of SVD gimbals on drawing [Roy K] 5. Get radiation detector dimensions for drawing. [Roy K] 6. Send CAD file to LBL. [Martin] . 7 Investigate feasibility of outer side of SmCo block at 300Êmr slope. [D. Walz] 8. Investigate machine implications of a 10 mm shift of the IP [Lattice group, Stan] 9. Investigate a four tip mask and reduced inner block radius. [Mike] 10. Number and location of holes in support barrel. [Gordon] 11. HOM RF calculations with new mask geometry [S. Heifets] attachments: Transparencies Next Meeting: 13:00 Friday 31 March 1995 in the Yellow room with TV to LBL