clic post-collision lines
DESCRIPTION
CLIC Post-Collision Lines. “bye, bye nano-meters”. “hello deca-tons”. CLIC Post-Collision Lines. Outline 1) Overview – Design Considerations 2) Present Conceptual Design 3) Beam Diagnostics in the Post-Collision Lines 4) Critical Issues 5) Next Step. - PowerPoint PPT PresentationTRANSCRIPT
3 September 2008 Konrad Elsener, CERN 1
CLIC Post-Collision Lines
“bye, bye nano-meters”
“hello deca-tons”
3 September 2008 Konrad Elsener, CERN 2
Outline
1) Overview – Design Considerations
2) Present Conceptual Design
3) Beam Diagnostics in the Post-Collision Lines
4) Critical Issues
5) Next Step
CLIC Post-Collision Lines
3 September 2008 Konrad Elsener, CERN 3
Information and help received from many colleagues
Ijaz AhmedHans BraunEnrico BravinLuca BrunoThibault Lefevre Daniel SchulteRogelio TomasHeinz VinckeThomas Zickler
Arnaud Ferrari (Uppsala)Volker Ziemann (Uppsala)
THANKS !
3 September 2008 Konrad Elsener, CERN 4
1) Overview – Design Considerationsconceptual design input:
- need to transport disrupted (spent) beam + beamstrahlung photons to final dump (14 MW) (vacuum chamber exit window etc.) also full beam without collisions
- need to deal with huge avalanche of particles of all energies (coherent pairs, total of 330 kW) (zero at ILC)
- “clean up” low energies, keep 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 5
1) Overview – design considerations
D. SchulteSendai, March 2008
~ 0.27 into photons
3 September 2008 Konrad Elsener, CERN 6
1) Overview – design considerations
Arnaud FerrariEUROTEV-Report2008-021
present CLIC parameters
disrupted beam at interaction point
3 September 2008 Konrad Elsener, CERN 7
1) Overview – design considerations
Daniel SchulteSendai, March 2008
coherent pairs at interaction point
3 September 2008 Konrad Elsener, CERN 8
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
- vertical “chicane” (2 x 3.2 mrad at 1.5 GeV); use 2 x 4 deflection magnets
- intermediate collimators and dumps for low energy tails and for opposite sign particles from coherent pairs; losses <100 W per magnet
- allow non-colliding beam to grow to acceptable size (to protect vacuum chamber exit window + dump, at ~150 m)
3 September 2008 Konrad Elsener, CERN 9
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
“C”-magnets
“window-frame” magnets
dump (6m long)
collimators(90 cm long)
beamstrahlung photons
3 September 2008 Konrad Elsener, CERN 10
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
disrupted beam+ same sign coherent pairs
beamstrahlung photons
1.5 TeV
300 GeV
90 cm
SIDE VIEW
3 September 2008 Konrad Elsener, CERN 11
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
“window-frame” magnets
“C”-magnets
3 September 2008 Konrad Elsener, CERN 12
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
disrupted beam at final dump
3 September 2008 Konrad Elsener, CERN 13
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
power deposition in collimators and dumps
3.7 MW
10.0 MW
170
kW
140
kW
8 k
W5 k
W2 k
W
3 September 2008 Konrad Elsener, CERN 14
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
typical weight of magnets
90
t
90
t
55
t
30
t
10
t
3 September 2008 Konrad Elsener, CERN 15
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
(both need to be in BDS)
Vague ideas about measuring opposite sign coherent pairs before/in dump(NB. 170 kW dump – instrumentation not obvious !) cf. Volker Ziemann, EuroTeV-Report 2008-016 – not treated here
somewhat more clear ideas about luminosity monitoring devices (below)
3 September 2008 Konrad Elsener, CERN 16
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(P. Eliasson et al., CLIC note 669 (EPAC 2006))
- measurement per bunch train possible (156 ns, 50 Hz)- measurement per bunch “impossible”-> will attempt to “cut” train into few slices
relative changes to luminosity – absolute value from “slow” detectors
3 September 2008 Konrad Elsener, CERN 17
e+e- pair production
2.5E+12 photons in 156 ns;energies up to 1.5 TeV
->
5E+9 charged particles
->
Opt. Trans. Radiationin thin screen(observation with CCDor photomultiplier)
3) Beam Diagnostics in the Post-Collision Lines by Enrico Bravin, July 2007
3 September 2008 Konrad Elsener, CERN 18
3) Beam Diagnostics in the Post-Collision Linesby Volker Ziemann (Uppsala)
016
pair production
-> Cerenkov light -> observe with photomultiplier(~ 2E+5 Cerenkov photons per 3.7E+9 particles in a bunch)
3 September 2008 Konrad Elsener, CERN 19
4) Critical Issueslevel 1
- main beam dumpif water dump at 10 bar –> entrance window ?if not, what dump ?
(cf. 4 MW p-beam dump, EDMS No. 348474)- 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
typical CLICquad
10 cm
2.30 m
3 September 2008 Konrad Elsener, CERN 21
lateral space – examples
ILC dump
3 September 2008 Konrad Elsener, CERN 22
lateral space – examples
TESLA
3 September 2008 Konrad Elsener, CERN 23
5) Next Step
address level 1 issues
- organize working group
MARS / GEANT / FLUKA /,dumps + windows, radiation protection,(later: cooling + ventilation experts, magnets, beam diagnostics)AB-ATB group is interested to participate (Sept. 2008)
- find help from experts outside CERNcontacts before/during CLIC workshop (Oct. 2008)
NB. this coll. with Uppsala ends – Arnaud Ferrari is searching for HiggsHELP needed for beam simulations (GUINEAPIG, DIMAD, PLACET, etc.)
3 September 2008 Konrad Elsener, CERN 24
spare slides
3 September 2008 Konrad Elsener, CERN 25
500 GeV
- not studied in any detail (a priori: lower magnet currents should be o.k.)
- much closer to ILC situtation
-> will allow more ambitious monitoring of beam parameters (if required)
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)
3 September 2008 Konrad Elsener, CERN 29
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
Coherent Pairs – same sign particle angles at IP
3 September 2008 Konrad Elsener, CERN 30
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
Coherent Pairs – opposite sign particle angles at IP
3 September 2008 Konrad Elsener, CERN 31
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
first “window-frame” magnet
3 September 2008 Konrad Elsener, CERN 32
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
“C-type” magnet
3 September 2008 Konrad Elsener, CERN 33
2) Present Conceptual Design (Arnaud Ferrari, Uppsala)
intermediate dump (beam view)
3 September 2008 Konrad Elsener, CERN 34
(a wild try – K.E.)
intermediate dump
3 September 2008 Konrad Elsener, CERN 35
typical OTR monitor arrangements:
e.g. “intensity” and 2D-profile e.g. “intensity” onlyCCDoptics
PMpolished tube
works at >10E+11 part.good pos. resolution(+ size of beam)
“rad. hard” cameras exist...very slow
almost “single counting”;very fast (< 1 ns)
“radiation hard”
sensitive to “direct hits”
ATTENTION: No absolute calibration for the intensity !!
3 September 2008 Konrad Elsener, CERN 36
background No. 1: synchrotron radiation photons pair production -> < 50 MeV particles
solution (?): 10-3 Tm magnetic field (-> 15 mrad at 20 MeV) (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 37
Rad-Hard Magnets
• Polyimide insulation up to 108 Gy• Mineral Insulation Cable up to 1011 Gy
from E. Hirose and K. Tanaka (JPARC-nu facility)
3 September 2008 Konrad Elsener, CERN 38
Polyimide Insulation
Tensile strength of a cured BT resin
reinforced by Boron Free Glass Cloth.
BT resin
from E. Hirose and K. Tanaka (JPARC-nu facility)
3 September 2008 Konrad Elsener, CERN 39
• Typical magnets for JPARC-nu beam line
Q460
Insulator Polyimide ~ 108Gy
Bore diameter 20cm
Current 2500A
Weight 32ton
Voltage ~ 160V
Length 3m
from E. Hirose and K. Tanaka(JPARC-nu facility)
3 September 2008 Konrad Elsener, CERN 40
Mineral Insulation
Cable
from E. Hirose and K. Tanaka (JPARC-nu facility)
3 September 2008 Konrad Elsener, CERN 41Radiation resistant magnet for J-PARC (Q440MIC)from E. Hirose and K. Tanaka (JPARC-nu facility)