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Beam Delivery System Simulation and Detector Backgrounds

Beam Delivery System Simulation and Detector Backgrounds. Arlington Linear Collider Workshop January 9-11, 2003. Takashi Maruyama SLAC. “Collimation Task Force”. • Compare performance of the collimation system of TESLA, JLC/NLC and CLIC. • Review spoiler/absorber settings

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Beam Delivery System Simulation and Detector Backgrounds

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  1. Beam Delivery System Simulation and Detector Backgrounds Arlington Linear Collider Workshop January 9-11, 2003 Takashi Maruyama SLAC

  2. “Collimation Task Force” • Compare performance of the collimation system of TESLA, JLC/NLC and CLIC. • Review spoiler/absorber settings • Halo collimation • Particle loss calculation • Sync. radiation collimation NLC: S. Hertzbach, L. Keller, T. Markiewicz,T. Maruyama, T. Raubenheimer, A. Seryi, P. Tennenbaum, M. Woodley TESLA: O. Napoly, N. Walker CLIC: G. Blair, D. Schulte, F. Zimmermann FNAL: A. Drozhdin, N. Mokhov TRC: W. Kozanecki December 16 – 18, 2002 December 16 - 18, 2002

  3. Major source of detector background: Halo particles hitting beamline components generate muons and low energy particles. Halo particles generate sync. radiations that hit VXD. Beam-gas scattering generates low energy particles. Collimate Halo particles: Spoilers and Absorbers Collimation depth – (nxsx, nysy) Reduce halo size using Octupoles What is Halo, and How much: Drozhdin’s 1/x-1/y model Flat distribution with 50sx,50sx’,200sy,200sy’,3%DE/E Calculated halo ~10-6, but design collimation for 10-3. Background and collimation

  4. NLC Detector Masking Plan View w 20mrad X-angle LD – 3 Tesla SD – 5 Tesla R=1 cm 32 mrad 30 mrad Apertures: 1 cm beampipe at the IP 1 cm at Z = -350 cm

  5. 2001 Collimation System & FF integrated design Octupole Doublets FD A Final Focus Final Focuscollimation IP A Energy collimation FD Betatroncollimation A IP FD IP FD IP S SA SA SA A New scheme of the Collimation Section and Final Focus with ODs

  6. Beam Delivery Systems TESLA JLC/NLC CLIC

  7. Synchrotron radiations quads Photons from quads bends FF doublet aperture 1 cm Photons from bends

  8. cm Sync. Radiation vs. IP • Track particle with n• backward from IP to AB10. • Track particle to IP and generate sync. radiations.  Find sync. radiation edge as a function of (nx, ny). nx = 18.5  x+, 17.2  x- ny = 50.9  y  Find AB10 and AB9 apertures as a function of (nx, ny) xIP nx yIP ny

  9. Sync. Radiations at IP Quad Ng=7.3 Ne- Quad <Eg>=4.8 MeV Bend Log10(E) (GeV) Y Bend X (cm) X (cm)

  10. Spoiler/Absorber Settings for NLC Spoilers/Absorbers Settings for NO OCT Half apertures sx sy X Y (um) Sp1 ~ SP4 settings with OCT x2.5

  11. Spoiler/Absorber Settings TESLA CLIC

  12. 10-5 Halo Model X’ Y’ X (cm) Y (cm) • 1/x and 1/y density over Ax = (6 – 16)x and Ay = (24 – 73)y – NLC/CLIC Ax = (7 – 18)x and Ay = (40 – 120)y – TESLA • E/E = 1% (Gaussian) • Halo rate 10-3 y (cm) x (cm)

  13. Particle loss distribution in NLC OCT-OFF ESP 42% to IP EAB AB7 OCT-ON 82% to IP AB10 DP2 Z (m)

  14. Integral Particle Loss Distribution

  15. Integral Particle Loss Distribution NLC/TESLA/CLIC

  16. 250 GeV/beam Muon Endcap Background Bunch Train =1012 Engineer for 10-3 Halo Calculated Halo is 10-6 Collimation Efficiency 105

  17. Muon Background

  18. Beam Gas Scattering

  19. Detector Background from Beam Gas Scattering At 50 nT, 8.5 hits/train within +/- 15 m of IP 2.5 hits/train on 1.2 cm VXD. If the vacuum is reduced to 1 nT in the last 250 m of IP, 0.2 hits/train within +/- 15 m of IP 0.05 hits/train on 1.2 cm VXD.

  20. Summary • “Collimation Task Force” has been studying the beam delivery system of TESLA, JLC/NLC and CLIC. • FF absorbers are set so that no sync. radiations hit the detector apertures. • Assuming 10-3 halo, the particle loss is < 10-8 in FF and the muon background is tolerable. • Octuples allow x2.5 looser spoiler settings. • Beam gas background in VXD is 0.05 hits/train if the vacuum is 1 nT.

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