1. The Simulation of the HEC What is presently in the description in GeoModel as presented by Joe Boudreau versus What should be in…

2. What is in… All sizes warm …but the simulated HEC is cold! Massive Objects: –Copper –Argon –Kapton Boards (one per gap) Tie Rods Circular Iron Cylinders 1/32 of 2π ; R max to R min ; z 1 to z 2

3. Copper warm dimensions. 7 types of PAD boards.

4. Copper & Liquid Argon (next slide: zoom in on argon gap)

5. One Kapton Board Per Gap Copper Kapton Argon

6. Tie Rod Diameter (not Spacer Diameter) So material is “in” to good approximation, but I do not know about dead readout volume at each spacer

7. What should be in Principles: Average outer boundaries correct (no warm dimensions) Density correct (so total material is correct) Significant areas where the detector has inactive regions (so signal is correct) Ability to test failure modes (such as: one HV gap failing) Propose: 3(?) complexity levels to match required detail of simulation Use the simplifying approximation: thermal expansion coefficient steel is same as copper.

8. Objects with their APPROXIMATE effect Tie Rods / Spacers (steel cylinders) –Dead Area ~ 0.4% –Increased Material ~ 0.1% Connecting Bars (square bar) –Increased Material ~ 1.8% (outside nominal active volume) Tie Bars (mixture of Ar/Cu at inner ~ 2cm) –Decreased Material ~ 0.1% 2 mm Inter-module gaps (Ar replacing the copper) –Dead Area ~ 0.8% –Decreased Material ~ 0.7%

9. Proposal Complexity 0 –Just Copper, Kapton and Argon –4 readout sub-gaps per Cu/Cu Gap –Possibility of a single sub-gap, in gap n not operating Complexity 1, add: –Dead Area of Tie Rods & Spacers –Connecting Bars Material –2 mm Inter-module gaps (Dead Area & Decreased Material) Complexity 2, add: – Tie Rods/Spacers Material – Tie Bars (mixture of Ar/Cu at inner ~2cm) – Other (Perhaps: Cu notches, honeycomb, patch panels, etc. if found useful) Following slides show each of these for the benefit of the non-expert

10. Tie Rods (7 in each module) The tie rods are the 7 steel rods with white tips sticking up out of the stack of copper. These are in the simulation at present. 8.5mm rings go on these tie rods to set the separation of the copper plates. Tie Rod Diameter: 12/16 mm (front/rear) Spacer Diameter: 16.9/22.9 mm (front/rear)

11. Connecting Bars (outer radius) The connecting bars hold the wheel together at the outer radius… 50.00mm x 147.25mm x (817(F) or 962(R))mm Almost solid steel…

12. Tie-bars (inner radius) The inner 20.00mm of the HEC is not solid copper but of a slightly reduced stopping density due to copper bars that hold the wheel together

13. 4 readout gaps between each copper plate

14. 2 mm Inter-module gaps There is a nominal 2 mm gap between each module to allow assembly of the wheel