1. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field1 On the Magnetic-field Requirements for the LC TPC OUTLINE of TALK Status of Discussion Status of Discussion Magnetic-field issue Magnetic-field issue -The systematic uncertainty -The B-field Map for the LC TPC The Aleph B-Map The Aleph B-Map Recommendations and Ideas Recommendations and Ideas OUTLINE of TALK Status of Discussion Status of Discussion Magnetic-field issue Magnetic-field issue -The systematic uncertainty -The B-field Map for the LC TPC The Aleph B-Map The Aleph B-Map Recommendations and Ideas Recommendations and Ideas

2. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field2 e.g.with precision measurements of the Higgs e.g.with precision measurements of the Higgs Expt (GeV)Decay Channel (GeV/c 2 )ln(1+s/b) 115 GeV/c 2 1ALEPH206.74-jet114.31.73 2ALEPH206.74-jet112.91.21 3ALEPH206.54-jet110.00.64 4L3206.4E-miss115.00.53 5OPAL206.64-jet110.70.53 6Delphi206.74-jet114.30.49 7ALEPH205.0Lept118.10.47 8ALEPH208.1Tau115.40.41 9ALEPH206.54-jet114.50.40 10 OPAL205.44-jet112.60.40 Goal: to revisit the Higgs… Goal: to revisit the Higgs…

3. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field3 On the Magnetic-field Requirements for the LC TPC…… STATUS OF DISCUSSION Dan Peterson and I presented two different viewpoints at an LDC meeting at Snowmass05. Dan Peterson and I presented two different viewpoints at an LDC meeting at Snowmass05. Both of these viewpoints are based on simplified arguments to help understand the effects. Both of these viewpoints are based on simplified arguments to help understand the effects. Here are mine: “back-of-the envelope” must be done carefully. Here are mine: “back-of-the envelope” must be done carefully. Christian Grefe is analyzing the field map for the LP which will be testing some of these ideas. Christian Grefe is analyzing the field map for the LP which will be testing some of these ideas. Simuation work can help understand more details of the issue. Simuation work can help understand more details of the issue. STATUS OF DISCUSSION Dan Peterson and I presented two different viewpoints at an LDC meeting at Snowmass05. Dan Peterson and I presented two different viewpoints at an LDC meeting at Snowmass05. Both of these viewpoints are based on simplified arguments to help understand the effects. Both of these viewpoints are based on simplified arguments to help understand the effects. Here are mine: “back-of-the envelope” must be done carefully. Here are mine: “back-of-the envelope” must be done carefully. Christian Grefe is analyzing the field map for the LP which will be testing some of these ideas. Christian Grefe is analyzing the field map for the LP which will be testing some of these ideas. Simuation work can help understand more details of the issue. Simuation work can help understand more details of the issue.

4. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field4 Prepared LC Note at Snowmass05 time… …based on experience with Aleph TPC Is being updated now

5. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field5 Physics determines detector design « momentum: d(1/p) ~.9x10 -5 /GeV (TPC only) ~.3x10 -5 /GeV(w/IP) (1/10xLEP ) e + e -  ZH  ll  X goal:  eV  tracking efficiency: 98% (overall ) excellent and robust tracking efficiency by combining vertex detector and TPC, each with excellent tracking efficiency

6. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field6 TPC central-tracker tasks ISSUES –Performance/Simulation –Design –Backgrounds, alignment, corrections

7. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field7 Snowmass05 list of performance/simulation issues is being revisited for the ILD optimization –Momentum precision needed for overall tracking? –Momentum precision needed for the TPC? –Arguments for dE/dx, Vº detection –Requirements for 2-track resolution (in rφ and z)? track-gamma separation (in rφ and z)? –Tolerance on the maximum endplate thickness? –Tracking configuration Calorimeter diameter TPC Other tracking detectors –TPC outer diameter –TPC inner diameter –TPC length –Required B-mapping accuracy in case of non-uniform B- field?

8. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field8 Performance: LC Note LC-DET-2007-005 w/ MPGD!

9. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field9 The systematic uncertainty

10. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field10 The systematic uncertainty So, I started writing this note aggressively assuming the linear model and δx o ≡ δσ o = 10μm. When I showed an early draft to Dean, he said, “you should add them quadratically” This is correct as you see next… 

11. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field11 The systematic uncertainty (θ denotes azimuthal angle in this paper) Aleph Note by Steve Thorn: ALEPH 94-162, PHYSIC 94-138

12. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field12 The B-field http://wisconsin.cern.ch/~wiedenma/TPC/Distortions/CERN_LC.pdf

13. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field13 The B-field http://wisconsin.cern.ch/~wiedenma/TPC/Distortions/CERN_LC.pdf

14. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field14 The systematic uncertainty

15. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field15 The B-field Corrections exact if B-field known exactly; so what must B accuracy be? The relevant equations for movement of drifting electrons in B-field http://wisconsin.cern.ch/~wiedenma/TPC/Distortions/CERN_LC.pdf

16. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field16 The B-field The ‘standard’ TPC requirement for the B-field homogeneity has been (from the LC Note): The B-field The ‘standard’ TPC requirement for the B-field homogeneity has been (from the LC Note):

17. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field17 From the LC Note… ◦

18. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field18 From the LC Note… ◦

19. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field19 From the LC Note… ◦

20. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field20 From the LC Note… ◦

21. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field21 The Aleph B-map…

22. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field22 From the LC Note… Problems: - Different coil configuration between mapping and running - Hall plate drifts - Temperature drifts  Aleph should have taken more time for the calibration of various effects and mapped with more configurations.

23. 07/03/2008 Ron Settles MPI-Munich ILDMeeting@Sendai: TPC B-field23 B-field Map for the ILD Aleph map-accuracy good enough for the LC TPC, be we can profit from experience and do better: Lay out map to achieve better than 0.2‰ as was originally planned in Aleph. Construct main detector coil to adhere to ‘2mm condition’. Establish tolerances with careful simulation: Do same for stray fields of MDI magnets. Mount matrix of Hall plates on LCTPC to monitor/check while running. Devise model including all material to compare with Hall-plate matrix.