RA D FT CLIC PostCollision Lines VE bye

RA D FT CLIC Post-Collision Lines VE “bye, bye nano-meters” N IO RS “hello deca-tons” 3 September 2008 Konrad Elsener, CERN 1

Outline 1) Overview – Design Considerations 2) Present Conceptual Design 3) Beam Diagnostics in the Post-Collision Lines 4) Critical Issues 5) Next Steps 3 September 2008 Konrad Elsener, CERN 2

Information and help received from many colleagues Ijaz Ahmed Hans Braun Enrico Bravin Luca Bruno Thibault Lefevre Daniel Schulte Rogelio Tomas Thomas Zickler Arnaud Ferrari (Uppsala) Volker Ziemann (Uppsala) THANKS ! 3 September 2008 Konrad Elsener, CERN 3

1) Overview – Design Considerations conceptual design input: - need to transport disrupted (spent) beam + beamstrahlung photons to final dump (14 MW) (vacuum chamber exit window / dump entrance window) also full beam without collisions - need to deal with huge avalanche of particles of all energies (coherent pairs, total of 658 k. W) (zero at ILC) - “clean up” low energies, but small particle losses in magnets - need to install some beam diagnostics (very modest w. r. t. ILC) -> stay clear of the incoming beam (20 mrad crossing angle) -> minimize background in the experiment (backscattering) 3 September 2008 Konrad Elsener, CERN 4

1) Overview – design considerations D. Schulte Sendai, March 2008 3 September 2008 Konrad Elsener, CERN 5

1) Overview – design considerations 2007 CLIC parameters Arnaud Ferrari EUROTEV-Report 2008 -021 3 September 2008 Konrad Elsener, CERN 6

1) Overview – design considerations D. Schulte Sendai, March 2008 3 September 2008 Konrad Elsener, CERN 7

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) - vertical “chicane” (2 x 3. 2 mrad); use 2 x 4 deflection magnets - intermediate collimators and dumps for low energy tails and opposite sign particles from coherent pairs; losses: <10 W per magnet - allow full beam to grow to acceptable size (to protect exit window, eg. at 150 m) 3 September 2008 Konrad Elsener, CERN 8

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) “window-frame” magnets “C”-magnets 3 September 2008 Konrad Elsener, CERN 9

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) “window-frame” magnets 3 September 2008 “C”-magnets Konrad Elsener, CERN 10

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) SIDE VIEW beamstrahlung photons 1. 5 Te. V disrupted beam + same sign coherent pairs 90 cm 300 Ge. V 3 September 2008 Konrad Elsener, CERN 11

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) disrupted beam at final dump 3 September 2008 Konrad Elsener, CERN 12

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) 172 k. W power deposition in collimators and dumps 3. 7 MW 143 k. W 7. 8 k. W 4. 7 k. W 1. 8 k. W 10. 0 MW 3 September 2008 Konrad Elsener, CERN 13

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) 3 September 2008 90 t 10 t 30 t 55 t 90 t typical weight of magnets Konrad Elsener, CERN 14

3) Beam Diagnostics in the Post-Collision Lines NB. Large number of coherent pairs imposes less ambitious diagnostics (w. r. t. ILC) in the post-collision lines - no energy measurement - no polarimeter Vague ideas about measuring opposite sign coherent pairs before/in dump (NB. 325 k. W dump – instrumentation not obvious !) cf. Volker Ziemann, Euro. Te. V-Report 2008 -016 – not treated here slightly more clear ideas about luminosity monitoring devices (below) 3 September 2008 Konrad Elsener, CERN 15

3) Beam Diagnostics in the Post-Collision Lines luminosity monitoring – crucial item various detectors will measure luminosity (. . . but: very slow. . . ) need fast signal for monitoring / correcting beams number of beamstrahlung photons is related to the luminosity - measurement per bunch train possible (156 ns, 50 Hz) - measurement per bunch “impossible” - will attempt to “cut” train in a few slices relative changes to luminosity – absolute value from “slow” detectors 3 September 2008 Konrad Elsener, CERN 16

3) Beam Diagnostics in the Post-Collision Lines by Enrico Bravin, July 2007 e+e- pair production 2. 5 E+12 photons in 156 ns; energies up to 1. 5 Te. V -> 5 E+9 charged particles -> OTR in thin screen (observation with CCD or photomultiplier) 3 September 2008 Konrad Elsener, CERN 17

3) Beam Diagnostics in the Post-Collision Lines by Volker Ziemann (Uppsala) m+m- pair production -> Cerenkov light -> observe with photomultipliler 016 3 September 2008 Konrad Elsener, CERN 18

3) Beam Diagnostics in the Post-Collision Lines 3 September 2008 Konrad Elsener, CERN 19

4) Critical Issues level 1 - main beam dump if water dump at 10 bar –> entrance window ? if not, what dump ? (cf. 4 MW p-beam dump) - radiation in the post-collision line –> equipment, water, air level 2 - cooling of dumps and collimators / material choice - cavern height / need for crane / - lateral free space (vs. incoming beam) - longitudinal space (need “stretched” version ? ) -> magnet design - synchrotron radiation - background in luminosity monitors -> simulations 3 September 2008 Konrad Elsener, CERN 20

lateral space - examples 10 cm typical CLIC quad 3 September 2008 2. 30 m Konrad Elsener, CERN 21

lateral space – examples ILC dump 3 September 2008 Konrad Elsener, CERN 22

lateral space – examples TESLA dump 3 September 2008 Konrad Elsener, CERN 23

5) Next Step address level 1 issues - organize working group FLUKA, dumps+windows, radiation protection, cooling + ventilation experts (later: magnets, beam diagnostics) AB-ATB group will propose experts in Sept. 2008 - find help from experts outside CERN 3 September 2008 Konrad Elsener, CERN 24

spare slides 3 September 2008 Konrad Elsener, CERN 25

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) 3 September 2008 Konrad Elsener, CERN 26

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) 3 September 2008 Konrad Elsener, CERN 27

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) 3 September 2008 Konrad Elsener, CERN 28

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) first “window-frame” magnet 3 September 2008 Konrad Elsener, CERN 29

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) “C-type” magnet 3 September 2008 Konrad Elsener, CERN 30

2) Present Conceptual Design (Arnaud Ferrari, Uppsala) intermediate dump (beam view) 3 September 2008 Konrad Elsener, CERN 31

(a wild try – K. E. ) intermediate dump 3 September 2008 Konrad Elsener, CERN 32

typical OTR monitor arrangements: e. g. “intensity” and 2 D-profile e. g. “intensity” only CCD optics PM polished tube works at >10 E+11 part. good pos. resolution (+ size of beam) almost “single counting”; very fast (< 1 ns) “radiation hard” “rad. hard” cameras exist. . . very slow sensitive to “direct hits” ATTENTION: No absolute calibration for the intensity !! 3 September 2008 Konrad Elsener, CERN 33

OLD - 2007 < 1. 5 Te. V. . . > 200 Ge. V 3 September 2008 Konrad Elsener, CERN view through last C-magnet in beam direction (dimension in cm) 34

background No. 1: synchrotron radiation photons pair production -> < 50 Me. V particles solution (? ): 10 -3 Tm magnetic field (-> 15 mrad at 20 Me. V) (if possible, sweep low energy particles in H-plane, observe OTR light in V-plane) use “small” OTR screen at 5 m from converter / magn. field (e. g. diameter 30 mm OTR screen) background No. 2: scattered electrons/positrons of all kinds -> to be studied background No. 3: neutrons (stay far away from IP and from dumps) -> to be studied 3 September 2008 Konrad Elsener, CERN 35