Preliminary Design of m + m - Higgs Factory Machine-Detector Interface

Transcription

1 Fermilab Accelerator Physics Center Preliminary Design of m + m - Higgs Factory Machine-Detector Interface Nikolai Mokhov Y. Alexahin, V. Kashikhin, S. Striganov, I. Tropin, A. Zlobin Fermilab Higgs Factory Muon Collider Workshop UCLA March 21-23, 2013

2 Outline From 1.5-TeV Muon Collider to Higgs Factory Source of Backgrounds and Heat Loads at HF Related Tools Developments IR Magnets and Lattice MARS Models MDI Design First Results on HF Detector Backgrounds First Results on HF IR Heat Loads Conclusions 2

3 1.5-TeV Muon Collider MARS15 Model 3

4 1.5-TeV MC MDI and 4 th Concept Detector Model Tight tungsten masks between and liners inside all magnets, dipole component in quads Optimized tungsten nozzle: 10 deg at cm 5 deg at cm R in = 0.36 cm at z=100 cm BCH 2 cladding Sophisticated shielding: W, iron, concrete & BCH 2 4

5 Machine Background Load to 1.5-TeV MC Detector MARS-calculated total number of particles per bunch crossing entering detector Particle Minimal 0.6-deg 10-deg Photon 1.5 x x 10 8 Electron 1.4 x x deg Muon 1.2 x x deg Neutron 5.8 x x 10 7 Charged hadron 1.1 x x 10 4 Time cuts in going to hit rates help substantially (see N. Terentiev X:Z=1:20 talk) 5

6 MDI-Related Higgs Factory Parameters Parameter Unit Value Circumference, C m 299 * cm 2.5 Muon total energy GeV 62.5 Number of muons / bunch Normalized emittance, N mm rad 0.3 Long. emittance, N mm 1.0 Beam energy spread % Bunch length, s cm 5.64 Repetition rate Hz 30 Average luminosity /cm 2 /s 2.5 6

7 HF Muon Decays: Backgrounds and Heat Loads l D = m, decays/m/bunch xing decays per bunch xing responsible for majority of detector background decays/m/s for 2 beams* Dynamic heat load: 1 kw/m** ~300 kw in superconducting magnets i.e. ~ multi-mw room temperature equivalent *) decays/m/s for 1.5-TeV MC **) 0.5 kw/m for 1.5-TeV MC 7

8 HF Final Focus 8

9 HF Detector Related MARS15 Developments Low-energy electromagnetic physics description improved and extended; in particular, EGS5 code was implemented below 20 MeV; as a result, e/g minimal energy can now be as low as 1 kev (compared to previous 200 kev), same as for charged hadrons, muons and heavy ions (minimal neutron energy is ev). Inclusive, hybrid and exclusive modeling of all physics process. The latter provides unity-weight option so desired by detector groups. Powerful ROOT geometry and visualization implemented; import & export of GDML geometries; lcsim SiD (H. Wenzel) implemented to a unified HF MDI/detector MARS model; new ROOT-MAD-MARS Beam Line Builder. 9

10 Low-Energy EMS in Si and Pb Black Goudsmit-Saunderson red MARS15, blue EGS5 10

11 320-mm IRQ MARS15 Model Nb 3 Sn cos-theta IR quadrupole design 11

12 500-mm IRQ MARS15 Model Nb 3 Sn cos-theta combined function IR quadrupole design. HF dipoles are also of a cos-theta type, contrary to 1.5-TeV MC OMD. 12

13 MDI Versions Considered So Far -1) No nozzles, no other MDI shielding, no IR collimators: just for reference, backgrounds and heat loads beyond technology capabilities 0) Minimal 7.6deg, 5 tungsten nozzles 1) Plus minimal tungsten collimators in IR and concrete collars in experimental hall 13

14 HF Nozzle Minimal Design Design principles 1. Inner aperture: 5 radius 2. Minimal outer angle q without overlap with current tracker and calorimeter 3. Tip-to-tip: ±2 z plus no extra shadowing for collision products 4. Minimal trap, both longitudinally and laterally 5. Just tungsten, no BCH 2 cladding (no room for it). Almost twice shorter, substantially thinner, 2.5 times shorter trap and no BCH 2 compared to the 1.5-TeV MC design: expect poorer performance 14

15 MARS15 Implementation and 5 Tests 15

16 SiD Detector and MDI in MARS15 SiD lcsim detector model: thanks to H. Wenzel 16

17 IR and MDI: Version 0 17

18 IR and MDI: Version 0 18

19 HF Neutron Background, V0 m - beam 19

20 Neutron Background in 1.5-TeV MC Detector Source: Muons from S < 200 m Others from S < 30 m n n Maximum neutron fluence and absorbed dose in the innermost layer of the silicon tracker for a one-year operation are at a 10% level of that in the LHC CMS at luminosity of cm -2 s

21 Notes on Origin in Lattice This is the combined effect of Angular divergence of secondary particles Strong magnetic field of dipoles in IR Tight tungsten masks Good performance of (1.5-TeV MC) optimized nozzles Confinement of decay electrons in the aperture (inside detector), forcing them to hit the nozzle on the opposite side of IP 21

22 HF Photon Background, V0 m - beam 22

23 Photon Background in 1.5-TeV MC Detector Total peak hit rate in the innermost layer of the silicon tracker per bunch xing without timing is noticeably higher than that in the LHC CMS at luminosity of cm -2 s

24 Power Density in HF IR Q1 and Q21, V0 Peaks are 5 to 10 times above the quench limit 24

25 Power Density in HF IR Q22 and Q3, V0 Peaks are up to 2 times above the quench limit 25

26 Power Density in HF IR Q4 and B1, V0 Peaks are 10 times above the quench limit 26

27 Energy Deposition in 1.5-TeV MC IR Quads a (cm) Q3 Q4 Q5 B1 Q6 Q2 Q1 5 y 5 x s (m) Q2 Q5 27

28 W Collimators in Interconnect Regions, V1 Concrete collar 28

29 m + m - Decays in HF IR, V1 29

30 Power Density: V0 V1 Q1, V0 Q1, V1 A factor of 3 to 80 reduction in peak values in IR quads 30

31 Electron Flux in HF IR, V1: Minimal Effect of Collimators on Backgrounds 31

32 Conclusions Consistent MARS15 model of Muon Collider HF IR and MDI with large aperture Nb 3 Sn magnets and SiD lcsim detector built, with first results on muon-decay detector backgrounds and heat loads to IRQ calculated. MDI configurations studied although with some encouraging outcome - revealed the difficulties in background suppression for the HF muon decay source term that is 24 times more intense than at 1.5-TeV MC. See further details on background properties and time gate and double-layer techniques in next two talks. Next steps: increase the nozzle outer angle to 15 deg (require changes to detector), further optimize IR collimators and MDI configuration and launch HF detector response simulations with the MARS-generated source. 32