Machine-Detector Interface Nikolai Mokhov Fermilab January 8, 2014

Scope of Machine-Detector Interface Efforts Developments of physics, geometry and tracking modules for adequate modeling of heat loads in superconducting (SC) magnets and particle backgrounds in Muon Collider (MC) detectors for both 125-GeV COM Higgs Factory (HF) and TeV MC. Building unified MARS model of Interaction Region (IR), entire ring (the source of backgrounds can be as long as 1/3 of the ring), magnets and other machine components along with corresponding collider detector. Design studies of Machine-Detector Interface (MDI) and SC magnets with thorough optimization of their component performance via full-scale Monte Carlo simulations. 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 hit reduction techniques in detector. January 8, 2014 Mokhov - MDI

MDI in 2012-2013 Completion of MDI design studies for 1.5-TeV COM Muon Collider (MC) with optimized protection systems for the IR and arc SC magnets as well as for detector, with source term files provided to detector community (July- December 2012) First round of design studies of the 125-GeV COM MC Higgs Factory (HF) with protection system proposed that exhibits feasibility of large- aperture cos-theta Nb3Sn IR and ring magnets, with manageable levels achieved for detector background loads; detailed exploration of hit rate reduction techniques for the MC detectors (January-December 2013, Overview in this talk) January 8, 2014 Mokhov - MDI

MDI-Related Higgs Factory Parameters Unit Value Circumference, C m 299 * cm 2.5 Muon total energy GeV 62.5 Number of muons / bunch 1012 2 Normalized emittance, N mmrad 0.3 Long. emittance, ||N mm 1.0 Beam energy spread % 0.003 Bunch length, s 5.64 Repetition rate Hz 30 Average luminosity 1031/cm2/s January 8, 2014 Mokhov - MDI

HF Muon Decays: Backgrounds and Heat Load lD = 3.896×105 m, 1.0266×107 decays/m/bunch xing (2 beams) 4.8×108 decays in IR per bunch xing responsible for majority of detector background 3.08×1011 decays/m/s for 2 beams* Dynamic heat load: 1 kW/m** ~300 kW in superconducting magnets i.e. ~ multi-MW room temperature equivalent *) 1.28×1010 decays/m/s for 1.5-TeV MC **) 0.5 kW/m for 1.5-TeV MC Note: Large-aperture high-field magnets (large bmax and et, reduced good field region) huge physical aperture in IP vicinity increased loads on detector January 8, 2014 Mokhov - MDI

MC Higgs Factory MARS15 Model MARS model of SiD-like detector with CMS upgrade-type tracker January 8, 2014 Mokhov - MDI

Current HF MDI in MARS15 January 8, 2014 Mokhov - MDI

50-cm ID IRQ2 and IRQ4 MARS15 Model Nb3Sn cos-theta combined function IR quadrupole design HF collider quad lengths: 0.5 ≤ L ≤ 2.05 m January 8, 2014 Mokhov - MDI

50-cm ID 8-T IR Dipoles MARS15 Model Coil ID: 32 and 50 cm in IR, 27 cm in CCS and MS and 16 cm in Arc HF collider dipole lengths: 2.25 ≤ L ≤ 4.1 m January 8, 2014 Mokhov - MDI

Tungsten Liners and Masks to Protect SC Magnets and Detector Reduce peak power density in inner Nb3Sn 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 January 8, 2014 Mokhov - MDI

BCS1 8-T Dipole with Elliptical Tungsten Liner Optimized individually in each magnet in the ring January 8, 2014 Mokhov - MDI

BCS1: Tungsten Mask and Power Density Geometrically tightest tungsten mask (L = 15cm) at the IP end of BCS1 dipole Ring center Optimized individually for each magnet interconnect region in the ring January 8, 2014 Mokhov - MDI

Peak Power Density: At the Target Ring center January 8, 2014 Mokhov - MDI

Dynamic Heat Load: At the Target “Warm” components 1.9K cold mass January 8, 2014 Mokhov - MDI

Higgs Factory Nozzle Design 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 (±2sz plus no extra shadowing for collision products) 5deg A dozen of configurations studied in 2013 in full MARS Monte-Carlo: V1. q = 7.6deg, aperture radius R = 5s, bare tungsten (UCLA HF WS, 03/13) V2. q = 15deg, aperture radius R = 4s, 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 q = 15deg January 8, 2014 Mokhov - MDI

MDI Design Efficiency Visually January 8, 2014 Mokhov - MDI

Particle Flux and Power Density in Q1 at z = 4.4m g n Ring center e± January 8, 2014 Mokhov - MDI

MDI Particle Flux Density g n m e± January 8, 2014 Mokhov - MDI

Backgrounds Entering Detector per Bunch Crossing Number of particles (Eth = 0.1-1 MeV) and Energy flux (TeV) Particle 1.5-TeV MC 10deg 125-GeV HF v2 v7x2s4 Photon # TeV 1.8×108 160 3.2×109 12000 2.8×108 2200 Electron # 1.0×106 5.8 1.2×108 9000 2.0×106 32 Neutron # 4.1×107 170 1.7×108 300 5.2×107 86 Ch. Hadron # 4.8×104 12 1.0×105 26 1.0×104 2.3 Muon # 8.0×103 184 2.8×103 8.2 <E>=23 GeV <E>=3 GeV January 8, 2014 Mokhov - MDI

Photon Fluence (cm-2) per Bunch X-ing v7x2s4 January 8, 2014 Mokhov - MDI

Tagged Decays & Loads on VXD Barrel v7x2s4: >10 peak reduction for g and e± compared to v2 Layer radii: 5.4, 9.45, 13.49, 17.55; 21.59 cm; -20 < z < 20 cm January 8, 2014 Mokhov - MDI

Background Suppression in VXD and Tracker 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 the 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. IP muon hit cluster inefficiency and surviving fraction of MARS background hit clusters vs. energy deposition Threshold at z=0 in innermost 200mm layer of barrel tracker (top) and outermost 75mm layer of barrel VXD (bottom). A factor of 2 efficiency at best. January 8, 2014 Mokhov - MDI

Beam Loss Power Distribution 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 for one beam for 3 nozzle configurations: Beam Loss Power Distribution 2-beam’s 200W on beampipe will need cooling: more material, more interactions There is a room for nozzle optimization 3.5 kW on each nozzle will require cooling system V2 96W V6 7W V7 0 January 8, 2014 Mokhov - MDI

SLAC HF MDI Studies (2) FLUKA model at ±25m from IP: magnets, v2-nozzle and some shielding; detector represented only as scoring planes. Results were compared against similar results from the MARS team and eventually both sets of background files were deemed compatible. The time distribution of neutrons is broader than that generated by MARS. Estimated timing-based efficiency in this simple model is lower compared to that from MARS/ILCRoot CMU group. January 8, 2014 Mokhov - MDI

MDI FY14 Plans Production runs for HF background files to feed detector community. Documentation of MARS results on the SC magnet protection system for the HF Collider and backgrounds in the HF detector. Build MARS model for 3-TeV MC: lattice, magnets, MDI. Perform initial studies of heat loads and backgrounds in 3-TeV MC. Launch massive MARS runs to design and optimize the SC magnet protection system for 3-TeV MC. Launch massive MARS runs to design and optimize the system to suppress backgrounds for 3-TeV MC. Perform FLUKA and Decay Turtle studies for 3-TeV MC. Perform studies on methods to suppress background hit rates in detector components for HF and 3-TeV MC. January 8, 2014 Mokhov - MDI

IBS MDI Schedule Collider Concept Specification Interface Parameters Technology Specification IBS Review Ready Date Higgs Factory 8/27/2014 12/25/2014 1/24/2015 1.5 TeV 3 TeV 4/24/2015 5/24/2015 > 5 TeV 7/28/2015 11/25/2015 12/25/2015 Ring-MDI Interface Parameters January 8, 2014 Mokhov - MDI

MDI Effort and Key Personnel Activity Personnel Institution MAP FTE MARS code development including NERSC mode N. Mokhov, S. Striganov, I. Tropin FNAL 0.15 MARS model of magnets, IR, ring, detector and MDI I. Tropin, N. Mokhov 0.35 Design and optimization of MDI and magnet protection 0.45 Production runs on background source terms at MDI S. Striganov, N. Mokhov, I. Tropin 0.25 Background rejection in detector N. Terentiev CMU 1.0 Decay Turtle and FLUKA modeling of backgrounds T. Markiewicz, T. Maruyama, L. Keller, U. Wienands, J.P. Delahaye, N. Graf SLAC Total 2.55 Tight connection with MAP Collider (Y. Alexahin) and Magnet (V. Kashikin, A. Zlobin) WGs as well as with MC Detector group (R. Lipton, H. Wenzel, V. Di Benedetto, A. Mazzacane) January 8, 2014 Mokhov - MDI