1.4 1.2 1 0.8 RESULTS 0.6 0.4 gem1 0.2 SETUP quartz1 blm4 0 -300 -200 -100 0 100 200 300 400 500 600 700 800 cry angle [ µ rad] FUTURE PLANS Status and plans of the UA9 experiment V.Previtali, on behalf on the UA9 collaboration LARP CM16 - Montauk, NY 15-18 May 2011
Outline 1.2 ✤ UA9 experiment: how a crystal could help the LHC experimental data INTRODUCTION smoothed function N coll /N cry 0.8 multi turn secondary 0.4 halo 0 0.02 0.015 d(N coll /N cry )/dk 0.01 0.005 0 1. angular scans -400 -350 -300 -250 -200 -150 -100 -50 0 DATA k [ µ rad] 2. collimator scans ANALYSIS RESULTS 3. scraper scans ✤ future changes in the SPS layout ✤ future changes in the SPS layout FUTURE PLANS ✤ from SPS to the LHC: letter of intents and ongoing ✤ from SPS to the LHC: letter of intents and ongoing studies studies -1- LARP CM16 - Montauk, NY - 15-18 May 2011
Outline 1.2 ✤ UA9 experiment: how a crystal could help the LHC experimental data INTRODUCTION smoothed function N coll /N cry 0.8 multi turn secondary 0.4 halo 0 0.02 0.015 d(N coll /N cry )/dk 0.01 0.005 0 1. angular scans -400 -350 -300 -250 -200 -150 -100 -50 0 DATA k [ µ rad] 2. collimator scans ANALYSIS RESULTS 3. scraper scans ✤ future changes in the SPS layout FUTURE PLANS ✤ from SPS to the LHC: letter of intents and ongoing studies -1- LARP CM16 - Montauk, NY - 15-18 May 2011
starting from the end: crystal collimation in the LHC INTRODUCTION UA9 is a Crystal Collimation experiment ✤ We want to prove the feasibility and the advantages of using a bent crystal as a primary ✤ collimator instead of a standard amorphous primary collimator. Why are we studying the crystal collimation option? -2- LARP CM16 - Montauk, NY - 15-18 May 2011
starting from the end: crystal collimation in the LHC INTRODUCTION UA9 is a Crystal Collimation experiment ✤ We want to prove the feasibility and the advantages of using a bent crystal as a primary ✤ collimator instead of a standard amorphous primary collimator. The Large Hadron Collider (LHC) POWERFUL DELICATE working temperature total energy 1.9 K 360 MJ per beam superconducting magnets Losses cannot be are very sensible to (totally) avoided energy releases Design loss rate Quench limit (0.2h beam (energy release limit) lifetime, 10 s) 7.8 10 6 p/s/m 4.3 10 11 p/s =(480 KW per beam) -2- LARP CM16 - Montauk, NY - 15-18 May 2011
starting from the end: crystal collimation in the LHC INTRODUCTION UA9 is a Crystal Collimation experiment ✤ We want to prove the feasibility and the advantages of using a bent crystal as a primary ✤ collimator instead of a standard amorphous primary collimator. The Large Hadron Collider (LHC) POWERFUL DELICATE working temperature total energy 1.9 K 360 MJ per beam superconducting magnets Losses cannot be are very sensible to Maximum (totally) avoided energy releases local Design loss rate Quench limit cleaning = 1.78 10 -5 [1/m] (0.2h beam (energy release limit) inefficiency lifetime, 10 s) 7.8 10 6 p/s/m 4.3 10 11 p/s =(480 KW per beam) -2- LARP CM16 - Montauk, NY - 15-18 May 2011
starting from the end: crystal collimation in the LHC INTRODUCTION UA9 is a Crystal Collimation experiment ✤ We want to prove the feasibility and the advantages of using a bent crystal as a primary ✤ collimator. The Large Hadron Collider (LHC) phase 1 system: single diffractive scattering the most basic limitation of the sophisticated collimation system: collimation losses receiving a small system ever… kick but a non negligible 108 collimators and Δ p/p escape the absorbers! collimation insertion but are immediately lost at … but still the first bending magnets limited! losses @ dispersion suppressor courtesy of C.Bracco -3- LARP CM16 - Montauk, NY - 15-18 May 2011
starting from the end: crystal collimation in the LHC INTRODUCTION UA9 is a Crystal Collimation experiment ✤ We want to prove the feasibility and the advantages of using a bent crystal as a primary ✤ collimator. The Large Hadron Collider (LHC) phase 1 system: single diffractive scattering the most basic limitation of the sophisticated Phase might be limited below the nominal collimation system: collimation performances. With the Phase 2 system losses receiving a small system ever… (metallic collimators and special collimators kick but a non negligible in cryogenic regions) simulations predict that 108 collimators and Δ p/p escape the 100% of the nominal settings can be reached. absorbers! collimation insertion but In perspective (LHC upgrade) there is still are immediately lost at … but still room for innovative collimation concepts like the first bending magnets crystals. limited! losses @ dispersion suppressor courtesy of C.Bracco -3- LARP CM16 - Montauk, NY - 15-18 May 2011
A crystal for collimation: the idea INTRODUCTION Present layout of the LHC collimation system: multi-stage cleaning. The primary collimators intercepts the primary beam halo - the halo is “sprayed” and intercepted downstream. 0 beam core primary halo 6 7 10 tertiary secondary halo halo >10 primary collimator sensitive equipment (60cm, CFC) aperture [ σ ] secondary collimator normalized (LHC arc ot IR triplet...) (1m, CFC) Absorber (1m, W) amorphous scatterer -4-
A crystal for collimation: the idea INTRODUCTION The idea: to use mechanically bent crystals (typically Si) as “ smart scatterers ” in replacement of primary amorphous collimators, to minimize the escaping particles. Primary collimator would be slightly retracted. 0 beam core primary halo 6 6.2 channeled beam 7 crystal 10 tertiary halo >10 >10 primary collimator, sensitive equipment retracted aperture [ σ ] secondary collimator normalized (LHC arc ot IR triplet...) (1m, CFC) Absorber (1m, W) crystal collimator -5-
UA9: SPS installation INTRODUCTION A crystal-based collimation insertion has been installed in the SPS LSS5 to test the ✤ crystal collimation concept. collimation region highly dispersive area beam core primary halo crystal TAL2 (10cm Al) LHC-type collimator (1m Cu) TAC (60 cm W) 45 m / 60 degrees 67 m / 90 degrees 45 m / 60 degrees The element apertures depend on the measurement type ✤ For each element, one or more detector are installed to check the losses in the specific ✤ element. -6- LARP CM16 - Montauk, NY - 15-18 May 2011
UA9: SPS installation INTRODUCTION in this region we measure: 1- Reduction of inelastic interaction ratio at the crystal ( angular scan ) 2- multi-turn channeling efficiency ( collimator scan ) collimation region beam core primary halo crystal TAL2 (10cm Al) LHC-type collimator (1m Cu) TAC (60 cm W) highly dispersive area in this region we measure: 3- Tertiary halo reduction in highly dispersive area ( scraper scan ) -7- LARP CM16 - Montauk, NY - 15-18 May 2011
UA9: SPS installation INTRODUCTION in this region we measure: 1- Reduction of inelastic interaction ratio at the crystal ( angular scan ) 2- multi-turn channeling efficiency ( collimator scan ) collimation region beam core primary halo crystal TAL2 (10cm Al) LHC-type collimator (1m Cu) TAC (60 cm W) highly dispersive area in this region we measure: 3 fundamental measurements 3- Tertiary halo reduction in highly dispersive area ( scraper scan ) -7- LARP CM16 - Montauk, NY - 15-18 May 2011
Outline 1.2 ✤ UA9 experiment: how a crystal could help the LHC experimental data INTRODUCTION smoothed function N coll /N cry 0.8 multi turn secondary 0.4 halo 0 0.02 0.015 d(N coll /N cry )/dk 0.01 0.005 0 1. angular scans -400 -350 -300 -250 -200 -150 -100 -50 0 DATA k [ µ rad] 2. collimator scans ANALYSIS RESULTS 3. scraper scans ✤ future changes in the SPS layout FUTURE PLANS ✤ from SPS to the LHC: letter of intents and ongoing studies LARP CM16 - Montauk, NY - 15-18 May 2011
1- angular scans: layout DATA ANALYSIS RESULTS measurement concept: the transverse positions of the different elements are kept constant while the crystal orientation is changed. The rate of inelastic losses at the crystal is measured by downstream detectors. 0 beam core primary halo ~4 ~5.5 crystal 67 m / 90 degrees TAC (60 cm W) garage position TAL2 LHC-type collimator aperture [ σ x ] (10cm Al) (1m Cu) normalized The main result is the channeling reduction factor , i.e. the ratio between the inelastic interaction rate in the crystal in amorphous w.r.t. channeling orientation. -8- LARP CM16 - Montauk, NY - 15-18 May 2011
1- angular scans: detectors DATA ANALYSIS RESULTS 4 different crystals .82m 34 m 3 m sci L crk 1 blm 4 gem 1 sci C 5 differerent detectors can be used to measure the inelastic interactions at crystal: 2 scintillators, 1 GEM,1 cherenkov and 1 BLM (ionization chamber). the detectors data are normalized with respect to the flux of primary particles lost (BCT derivative) -9- LARP CM16 - Montauk, NY - 15-18 May 2011
1- angular scans: measurement example DATA ANALYSIS RESULTS Crystal 3, 21 Oct 2010 h 12:19 1.4 amorphous amorphous Nuclear interaction rate [a.u.] 1.2 channeling orientation 1 0.8 0.6 0.4 sci L gem1 0.2 quartz1 blm4 0 -300 -200 -100 0 100 200 300 400 500 600 700 800 cry angle [ µ rad] time -10- LARP CM16 - Montauk, NY - 15-18 May 2011
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