Эксперимент UA9 в CERN Ю.М.Иванов, лаборатория мезоатомов Ученый Совет ОФВЭ ПИЯФ

Кристаллическая коллимация: от У-70 к LHC Ученый Совет ОФВЭ ПИЯФ – первое применение коротких изогнутых кристаллов кремния для вывода и коллимации протонов с энергией 70 ГэВ на У-70 в ИФВЭ – первое применение упругоквазимозаичных кристаллов кремния, наблюдение объемного отражения протонов с энергией 70 ГэВ в ИФВЭ и 1 ГэВ в ПИЯФ – коллаборация H8-RD22 в CERN: исследование объемного отражения 400 ГэВ протонов, многократного объемного отражения, каналирования и объемного отражения отрицательных частиц, излучения при объемном отражении электронов и позитронов – коллаборация UA9 в CERN: исследование кристаллической коллимации на протонном и ионном пучках SPS – коллаборация LUA9 в CERN: исследование кристаллической коллимации на протонном и ионном пучках LHC

Letter of Intent for an experiment at LHC (CERN) Ученый Совет ОФВЭ ПИЯФ

LoI представлено на LHCC 15 июня Ученый Совет ОФВЭ ПИЯФ

Местоположение UA9 на SPS SPS (BA5) DAQ (BB5) CCC Ученый Совет ОФВЭ ПИЯФ

UA9 hardware in 2011 Collimation region High dispersion area Ученый Совет ОФВЭ ПИЯФ

1m Cu, LHC-type collimator 10 cm Al scraper ~45m / Δμ =60°~ 67m / Δμ =90° ~ 45m / Δμ =60° Collimation regionHigh dispersion area UA9 basic layout Observables in the collimation area: Intensity, profile and angle of the deflected beam Local rate of inelastic interactions Channeling efficiency (with multi-turn effect) Observables in the high-D area: Off-momentum halo population escaping from collimation (with multi-turn effect) Off-momentum beam tails 60 cm W absorber crystal3 crystal4 not used in 2011 Medipix in a two sided Roman pot Ученый Совет ОФВЭ ПИЯФ

Residual imperfections: Residual torsion 1 μrad/mm Amorphous layer size 1 μ m Miscut 100 μ rad Crystals Schematic view of the residual miscut angle different paths for different vertical hit points different paths at small impact parameter Torsion is no longer an issue torsion over the beam size < critical angle full mitigation of the detrimental effects Torsion is no longer an issue torsion over the beam size < critical angle full mitigation of the detrimental effects Quasimosaic crystal 1.9 mm long Bent along (111) planes Non-equidistant planes d1/d2 = 3 Crystal 4 Strip crystal 2mm long Bent along (110) planes Equidistant planes Crystal Ученый Совет ОФВЭ ПИЯФ

Goniometer The critical angle governs the acceptance for crystal channeling 120 GeV θ c = 20 μrad 270 GeV θ c = 13.3 μrad Transfer function Non-linear part of the transfer function residual inaccuracy |δ ϑ | 10 μrad residual inaccuracy |δ ϑ | 10 μrad in a full angular scan the drive position changes by 300 µm around the initial value in the plotted range Ученый Совет ОФВЭ ПИЯФ

absorber BLMs Equivalent crystal kick[μrad] Ncoll/Ncry [-] Efficiency 70-85% channelin g kick collimator Channeling efficiency bycoll. scans ~45m / Δμ =60°~ 67m / Δμ =90° ~ 45m / Δμ =60° Proton beam at 120 GeV Crystal 3 Pb-ion beam at 120 GeV Efficiency 50-74% Ученый Совет ОФВЭ ПИЯФ

Loss rate counters absorber Loss rate reduction at the crystal ~ 67m / Δμ =90° Nuclear spray ×5÷8 reduction data simulation protons ×3 reduction data simulation Lead ions Loss rate reduction factor for protons 5÷8 for lead ions 3 σ tot (lead ions)=σ h +σ ed =5.5 b 10×σ tot (p) Loss rate reduction factor for protons 5÷8 for lead ions 3 σ tot (lead ions)=σ h +σ ed =5.5 b 10×σ tot (p) Ученый Совет ОФВЭ ПИЯФ

BLMs Off-momentum halo population 1. Linear scan made by the TAL2 (or Medipix) with the crystal in fixed orientation 2. angular scan of the crystal with the TAL2 (or the Roman pot) in fixed position in the shadow of the absorber Scraper (TAL2) Absorber off-momentum halo population ~45m / Δμ =60°~ 67m / Δμ =90° Off-momentum halo deflected in the dispersive area of the TAL2 Medipix in a two sided Roman pot P, Pb: diffractive scattering and ionization loss Nuclear spray Ученый Совет ОФВЭ ПИЯФ

Sextant 5: Crystal collimation insertion Main result from UA9 in 2011: with high beam intensity the loss reduction at the collimation insertion reproduced in all the sextants ! 10x amorphous channeling 5x amorphous channeling reduction of losses at the crystal collimator... and ~ 130 m downstream (dispersive area) Crystal at 5.6 σ Absorber at 7.6 σ Scraper at 9.3σ Ученый Совет ОФВЭ ПИЯФ

Perspective for 2012 The extension of UA9 to LHC is seen favorably by LHCC and by the accelerator directorate (to be announced soon) time allocation in LHC to be shared in between the machine and the experiments (however very limited) dedicated run time to avoid conflicts with the high-luminosity operation. UA9 in the North Area and in the SPS The main goal will be to validate scenarios, detectors and hardware for LHC Upgrade of the SPS experimental setup required crystal collimation scheme for the high-intensity SPS operation. Preliminary investigations based on UA9 experimental setup Later an ad-hoc setup is required. The collimation is requested at high-energy in pulsed mode Very demanding constraints on crystal acceptance and on goniometer stability 5 days in the SPS (4 with protons and 1 with Pb-ions) 5 weeks in H8 (3 with protons and 2 with Pb-ions) 5 days in the SPS (4 with protons and 1 with Pb-ions) 5 weeks in H8 (3 with protons and 2 with Pb-ions) UA9 request to the SPSC Ученый Совет ОФВЭ ПИЯФ

New hardware and priorities for 2012 SPS – 5 full days 1) High intensity, high flux operation for loss maps along the SPS 2) Operation with Pb-ions 3) Hardware test for LHC (crystals and goniometer) 4) Collimation efficiency of multi- strip crystals H8 – 5 weeks 1) Test of new crystals for LHC 2) Test of instrumentation for LHC 3) Deflection efficiency withPb-ions 4) x-ray spectraPXRas a tool to detect the crystal integrity Ученый Совет ОФВЭ ПИЯФ

Публикации Ученый Совет ОФВЭ ПИЯФ Experimental study of the radiation emitted by 180-GeV/c electrons and positrons volume-reflected in a bent crystal, Physical Review A 79, (2009) Observation of Multiple Volume Reflection of Ultrarelativistic Protons by a Sequence of Several Bent Silicon Crystals, Physical Review Letters 102, (2009) Observation of nuclear dechanneling for high-energy protons in crystals, Physics Letters B 680 (2009) 129–132 High-efficiency deflection of high-energy negative particles through axial channeling in a bent crystal, Physics Letters B 680 (2009) 301–304 Observation of channeling and volume reflection in bent crystals for high-energy negative particles, Physics Letters B 681 (2009) 233–236 First observation of multiple volume reflection by different planes in one bent silicon crystal for high-energy protons, Physics Letters B 682 (2009) 274–277

Публикации Ученый Совет ОФВЭ ПИЯФ Multiple volume reflections of high-energy protons in a sequence of bent silicon crystals assisted by volume capture, Physics Letters B 688 (2010) 284–288 Deflection of high-energy negative particles in a bent crystal through axial channeling and multiple volume reflection stimulated by doughnut scattering, Physics Letters B 693 (2010) 545–550 Probability of inelastic nuclear interactions of high-energy protons in a bent crystal, Nuclear Instruments and Methods in Physics Research B 268 (2010) 2655–2659 First results on the SPS beam collimation with bent crystals, Physics Letters B 692 (2010) 78–82

Публикации Ученый Совет ОФВЭ ПИЯФ Observation of multiple volume reflection by different planes in one bent silicon crystal for high-energy negative particles, EuroPhysics Letters, 93 (2011) Observation of parametric X-rays produced by 400 GeV/c protons in bent crystals, Physics Letters B 701 (2011) 180–185 Comparative results on collimation of the SPS beam of protons and Pb ions with bent crystals, Physics Letters B 703 (2011) 547–551 The UA9 experimental layout, JINST 6 T10002 (2011)