D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Discussion for the LP endplate See also: This project is supported by the US National Science Foundation (LEPP cooperative agreement) and an LCDRD consortium grant D. P. Peterson Cornell University, Laboratory for Accelerator-based ScienceS and Education

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate, As shown in Vancouver, … There was some question of the positioning of the field shaping bands relative to the modules.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate In the process of transferring the project to a different drafting technician. The endplate is blank, but it is being built up using functionality of the program which allows a more rapid design optimization.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Field Cage The field cage, with the Cornell end-flange, is now properly built up from the subcomponents. This will allow more rapid adaptation to the group decisions.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Assembly The assembly shows the “endplate” surface in-line with the first field band. This is wrong, and we would like to define this distance at this meeting.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate/band geometry Martin Killenberg has suggested 26 mm as the maximum module thickness from the endplate surface. This includes: structure 8mm pad plane 2mm 3GEM 6mm GEM gate 10mm sum 26mm. He suggested that all modules, including Micromegas without gate, be made to this thickness. The field bands would be made in-line with this module height. We could do this. One variation is that some of the structure would be below the surface of the endplate. In this sketch, the module rises 22mm above the endplate surface. The endplate surface has been repositioned to be in-line with the edge of the end-flange (which may be metal). File:EndplateFieldCageGeometry1

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate/band geometry Details from the previous page File:EndplateFieldCageGeometry1

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate/band geometry The Killenberg geometry places the bands at the surface of the gate. This implies that we would have a different field (relative to the drift field) in the region between the gate and the gas-amplification. This may not be the case. We should decide if we want to maintain the drift field after the gate and, if so, do we want the bands to extend beyond the gate. File:EndplateFieldCageGeometry2

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate/band geometry The effective end of the bands could be set with electrical taps to the bands. (Representative bands are shown in purple in the drawing.) These could be strategically placed to accommodate the various readout configurations without adding excess height to the modules. Of course, the stand-offs to provide bias potential to the uncovered regions would be tuned for each readout configuration. File:EndplateFieldCageGeometry3

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate/band geometry If we have specific endplates for each configuration, the height could be tuned with the endplate surface offset. Here, the endplate surface is moved in by 6mm to accommodate the 6mm height difference between a Micromegas module and a 3-GEM module.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Module locations This shows the layout with 10 modules. The new drafting work is starting with this design but with all modules having the same geometry. However, once the framework is in place to optimize the geometry, it will be a minor effort to redesign with the 7-module (all modules of the same geometry) design.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Stress relief test piece This shows the first in a series of “stress relief test pieces”. This has been cut with a center opening of 30cm wide. The “mullions” are the same size as proposed in the endplate drawing: 18mm at the widest width, 14mm in depth. This is the first baseline part, with no stress relief. It has been fully measured on a CMM. The mullion position is distorted upward by 500  m (0.020inch). The part is currently cut with 750  m oversize. It will be re-cut to the drawing dimensions, this week, and re-measured.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Stress relief test piece A close-up of the part shown in the previous slide.

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Module Modifications

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Module o-ring seal

D. Peterson, “LC-TPC LP endplate”, Valencia ILC Workshop, Endplate/band geometry, 09-Nov-2006