Machine-Detector Interface Nikolai Mokhov Fermilab February 19, 2014

“MDI Efforts”: Much Broader than MDI itself Developments of physics, geometry and tracking modules for adequate modeling of Muon Collider (MC). Building unified MARS model of Interaction Region (IR), entire ring (source of backgrounds can be as long as 1/3 of the ring), magnets and other machine components along with corresponding collider detector. Optimization design studies of Machine-Detector Interface (MDI) and MC magnets. The goal is two-fold:  Design SC magnet protection system that reduces heat loads to the tolerable limits and helps decrease background.  Further reduce background loads on detector components to manageable levels via MDI optimization and exploitation of background rejection techniques in detector. February 19, Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

Key MDI Accomplishments Since the August 2012 MAP Review DateDescription FY12 Q4 Comprehensive energy deposition and background studies for 1.5-TeV Muon Collider (MC) completed. Ultimate background files delivered to MC detector groups. FY13 Q1-Q2 MARS15 code with newly developed for MAP modules delivered. Concept specification for large-aperture Nb 3 Sn magnets for Higgs Factory (HF) Interaction region (IR) and storage ring. MARS models of magnets and SiD-like lcsim detector built. First results on muon-decay detector backgrounds and heat loads to IR quads delivered. FY13 Q3-Q4 MARS model of HF MDI and entire storage ring was built using consistent magnet field maps and geometry, with magnet protection system, optimized MDI, sub- detectors and experimental hall. Encouraging results on reduction of detector backgrounds and peak power density presented at MAP Collaboration meeting (MAP-13, Fermilab, June 2013) and at IPAC2013, Shanghai. Studies of timing and energy deposition threshold background rejection techniques in 1.5-TeV MC VXD and tracker detectors performed (CMU report). Beam loss studies in HF and first alternative look at HF backgrounds within FLUKA framework done (SLAC report). FY14 Q1 Optimization MARS runs of the SC magnet protection system completed with 100- fold reduction of heat load achieved. Optimized MDI configuration with substantial reduction of background load on detector delivered. February 19, 2014 Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)3

HF Muon Decays: Backgrounds and Heat Load February 19, D = 3.896×10 5 m, ×10 7 decays/m/bunch xing (2 beams) 4.8×10 8 decays in IR per bunch xing responsible for majority of detector background 3.08×10 11 decays/m/s for 2 beams* Dynamic heat load: 1 kW/m** ~300 kW in superconducting magnets i.e. ~ multi-MW room temperature equivalent *) 1.28×10 10 decays/m/s for 1.5-TeV MC **) 0.5 kW/m for 1.5-TeV MC Note: Large-aperture high-field magnets (large  max and  t, reduced good field region) huge physical aperture in IP vicinity increased loads on detector Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

MC Higgs Factory MARS15 Model February 19, MARS model of SiD-like detector with CMS upgrade-type tracker Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

HF MDI in MARS15 February 19, Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

50-cm ID IRQ2 and IRQ4 February 19, Nb 3 Sn cos-theta combined function IR quadrupole Q2 and Q4 design HF collider quad lengths: 0.5 ≤ L ≤ 2.05 m HF quad coil ID (cm) = 32 (Q1), 50 (Q2-Q4), 27 (CCS) and 16 (MS and Arc) MARS15 Model Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

50-cm ID 8-T IR Dipoles February 19, MARS15 Model HF collider dipole lengths: 2.25 ≤ L ≤ 4.1 m HF dipole coil ID (cm) = 50 (BIR1,2), 27 (CCS) and 16 (MS and Arc) Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

Tight Tungsten Liners and Masks Reduce peak power density in inner Nb 3 Sn cable to below the quench limit with a safety margin, from a hundred mW/g to ~1.5 mW/g Keep the HF lifetime peak dose in innermost layers of insulation below ~20 MGy Reduce dynamic heat load to the cold mass from 1 kW/m to ~10 W/m Suppress the long-range component of detector background February 19, Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

BCS1 8-T Dipole with Elliptical Tungsten Liner February 19, Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) Optimized individually in each magnet in the ring Towards engineering design: T=60-80 K, ~1000 W/m T=4.5 K, 7 W/m W linerVacuum gap 5-10 mm SS beam pipe ~3-5 mm Kapton insulation ~0.5 mm LHe channel ~2-3 mm Coil ~1000 W/m 7 W/m

BCS1: Tungsten Mask and Power Density Geometrically tightest tungsten mask (L = 15cm) at the IP end of BCS1 dipole February 19, Optimized individually for each magnet interconnect region in the ring Ring center Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

Peak Power Density in SC Coils February 19, Ring center Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) Design goal is met: mW/g < 1.5 mW/g

Dynamic Heat Load on Cold Mass February 19, Cold mass “Warm” components Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) Design goal is met: 1000 W/m ~10 W/m

Higgs Factory Nozzle Design February 19, Expect poorer performance compared to 1.5-TeV MC: geometrically larger aperture, almost twice shorter, substantially thinner, 2.5 times shorter trap and 3.5 longer tip-to-tip open region (±2  z plus no extra shadowing for collision products) A dozen of configurations studied in 2013 in full MARS Monte-Carlo: V1.  = 7.6deg, aperture radius R = 5 , bare tungsten (UCLA HF WS, 03/13) V2.  = 15deg, aperture radius R = 4 , BCH2 cladding (MAP13, 06/13)... Be pipe radius increased from 3 to 5cm, thoroughly optimized nozzle inner shape, additional W/Fe/Concrete shielding at MDI, tighter/thicker masks and magnet inner absorbers (liners) … V7x2s4. December 2013  = 15deg 5deg Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

MDI Design Efficiency Visually February 19, Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)  - beam

Particle Flux and Power Density in Q1 at z = 4.4m February 19, Ring center  e±e± n Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

MDI Particle Flux Density February 19, e±e±  n  Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

Feeding Detector Community February 19, To feed detector simulation community, typical background source terms at MDI surface are generated in MARS15 runs for a few % of a bunch crossing. For a full HF bunch crossing, one needs about 14,000 core-days and up to 100 GB of disk storage space. Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) E th =0.1 MeV E th =10 -9 MeV

Particle Backgrounds Entering Detector February 19, Particle 1.5-TeV MC 10deg 125-GeV HF V2 (MAP13 06/13) 125-GeV HF V7x2s4 (Dec. 2013) Photon N E 1.8× × × Electron N E 1.0× × × Neutron N E 4.1× × × Ch. Hadron N E 4.8× × × Muon N E 8.0× × Number of particles N (E > MeV) and energy flux E (TeV) entering detector per bunch crossing =23 GeV =3 GeV Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) ~1/50 =0.9 MeV =8 MeV =6 MeV =16 MeV

Photon Fluence at IP February 19, v7x2s4 Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) Ring center Photon fluence (cm -2 ) per bunch crossing

Tagged Decays; Loads on VXD Barrel February 19, Layer radii: 5.4, 9.45, 13.49, 17.55; cm; -20 < z < 20 cm. Here for  - beam only v7x2s4: >10 peak reduction for  and e ± compared to v2 Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014) Majority of background particles entering detector are from decays at |S| < m

Background Rejection in VXD and Tracker February 19, Carnegie Mellon University studies with ILCRoot using 1.5-TeV MC MARS source files Inefficiency of IP muon hits and surviving fraction of MARS background particle hits in VXD and Tracker Si detectors versus width of timing gate for hit time resolution of 0.5 ns. 4-ns gate provides a factor of a few hundred background rejection while maintaining >99% efficiency for hits from IP muons. Use of energy deposition threshold of ~20-50 keV improves rejection by additional factor of 2. Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

SLAC HF MDI Studies (1) Tracking studies using REVMOC and DECAY TURTLE codes One-beam loss power distribution around ring: Average power on Be beam pipe: one beam and 3 nozzle configurations: February 19, Beam Loss Power Distribution V296W V67W V70 Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

SLAC HF MDI Studies (2) FLUKA model at ±25m from IP: magnets, v2-nozzle and some shielding. Results on backgrounds are compatible with those from MARS team. February 19, Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

MDI FY14 Plans February 19, Higgs Factory: Production runs for background files to feed detector community. Upgrade MARS model of magnet protection systems towards engineering design with corresponding impedance and ANSYS analyses; re-run. Document results on magnet protection and detector backgrounds. Perform studies on background rejection in detector components. 3-TeV Muon Collider: Build MARS model: lattice, magnets, MDI. Perform initial studies of heat loads and detector backgrounds. Launch massive MARS runs to design and optimize SC magnet protection system and MDI to suppress backgrounds. Perform studies on background rejection in detector components. Perform preliminary FLUKA and Decay Turtle studies. Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)

FY14-FY15 MDI Effort and Key Personnel February 19, ActivityPersonnelInstitutionMAP FTE MARS code development including NERSC mode N. Mokhov, S. Striganov, I. TropinFNAL0.15 MARS model of magnets, IR, ring, detector and MDI I. Tropin, N. MokhovFNAL0.35 Optimization MARS runs towards design of MDI and magnet protection N. Mokhov, S. Striganov, I. TropinFNAL0.45 Production runs on background source terms at MDI S. Striganov, N. Mokhov, I. TropinFNAL0.25 Background rejection in detectorN. TerentievCMU1.0 Decay Turtle and FLUKA modeling of backgrounds T. Markiewicz, T. Maruyama, L. Keller, U. Wienands, N. Graf SLAC0.35 Total2.55 Tight connection with MAP Collider (Y. Alexahin) and Magnet (V. Kashikhin and A. Zlobin) WGs as well as with MC Detector group (R. Lipton, H. Wenzel, V. Di Benedetto, A. Mazzacane) Nikolai Mokhov | DOE Review of MAP (FNAL, February 19-20, 2014)