TOF0 TOF1 Ckov1 Iron Shield TOF2 Ckov 2Cal Diffuser Proton Absorber Iron Shield ISIS Bea m LN2 Option RICH Option LH Option PARTICLE ID - CKOV1 STATUS REPORT UM/UCL L. Cremaldi, G. Gregoire, D. Summers CKOV1  = 1/1000 =>  Acive aperature  cm Low energy MICE, MeV/c MICE Capable of measuring beamline purity. Device should exceed >4.0  ?? MICE COLLABORATION MEETING, RAL OCT2005

Beam Profiles at CKOV1 (dated) UM/UCL Accepted muons Accepted muons r=23cm r=10cm

Refractive Index Density G/cc dE/dx |min MeV/cm Pth Mu MeV/c Pth Pi MeV/c Nmu/Npi beta=1 Water C6 F LN LH , Low Index Radiators UM/UCL

MeV/c About ~100 pe x 2/3 light collection efficiency ~ 65 pes. Light Collection Uniformity issues !! About degrees of angular separation. Not Used (Ghislain, RICH ) Photo-ElectronsCerenkov Angle     LN2 Radiator for High Momentum UM/UCL

Benchmarck Design for TDR UM 4-MIRROR/PMT DESIGN r = 23 cm active aperature FC72 Radiator MeV/c  Z = 5cm LN2 Radiator MeV/c  Z = 10cm Light Collection Uniformity needed to be studied pions muons 280 MeV/c 10 cm LN2 240 MeV/c 10 cm LN pions muons 4.0  2.5  Radiator Vessel Light Box

Ray Tracing UM Mu 250MeV/c 10cm LN2 (x,y)= (0, 0) cm eff=71/89 Mu 250MeV/c 10cm LN2 (x,y)= (0, -5) cm eff=42/89 Collection Efficiency can vary significantly over the aperature for pi and mu.

Light Collection Scan 4 Mirror/PMT UM Mu /Pi separation very problematic at first look. Optimization leads difficult. Add PMT/Mirror (s) muons pions Npe 250MeV/c y=scan x=0cm 10cm LN2 y-cm

Light Collection Scan 8 Mirror/PMT UM PID quite ambiguous--> Central pion looks like Wing muon. (x,y) position should be known for more robust PID Algorithm. PID separation varies between 3.2  2.2  w (x,y) 250MeV/c y=scan x=0cm y-cm 300MeV/c y=scan x=0cm ~3.2  ~2.2  10cm LN2 Npe Inner Track Outer Track Outer Track Inner Track Outer Track Outer Track

Light Collection Scan 12 Mirror/PMT UM Npe ~3.2  250MeV/c y=scan x=0cm y-cm 10cm LN2 ~2.3  y-cm 300MeV/c y=scan x=0cm 10cm LN2 12 PMT/Mirror design with r=5cm central trigger scintillator leads to 2-3  separation. Trigger counter to define Inner and Outer Tracks. Inner Track Outer Track Outer Track Inner Track Outer Track Outer Track

LN2 Summary UM LN mirror/pmt design difficult to optimize. LN2 +8/12 mirror/pmt model looks more promising. Central trigger counter should be used to define Inner and Outer tracks for PID algorithm. 4  separation difficult/miracle over full MeV/c. Trigger cnt Light box Radiator

mu 26 o -> 0.450rd --> 4.5 cm/bounce --> 4-5 bounces  = = 62% pi 18 o -> 0.310rd --> 3.1 cm/bounce --> 7-8 bounces  = = 45% Top view 23cm 50cm --> ( ) ns ns slewing 75cm --> ( )ns +-0.2ns slewing muon pion PMT 10cm LN218 o 26 o  burst 450ps Timimg off leading 1-2 pe?? TOFC Concept UM

240MeV/c 260MeV/c 280MeV/c300MeV/c Timing&Pulse Height Simulation UM Pion signals arrive later and straggle in. Simulations suggest that with  t~ 250ps resolution one might resolve the mu-pi. 2” pmts needed to collect light. Photonis XP2020 Hamamatsu ns0

X=0. Y=0. cmX=20. Y=0. cm X=10. Y=10. cm X=5. Y=5. cm mu pi Time (ns) PMT # Pattern Recognition with 12 PMTs UM

Plane mirror Simple geometry 350 mm 585 mm Electrons Muons Pions 1200 mm X Y Pixel size = 2 x 2 mm 2 20-mm thick radiator ( Colors correspond to different particle species ) Sample size: 50 k pions 50 k muons 50 k electrons Diam. 250 mm 5 RICH Option - G. Gregoire UCL

(at the expense of light output) Large detecting plane due to plane mirror Optical focusing needed  100% light collection efficiency mandatory  R  3 mm   e Shifts due to refraction in the thicker radiator Conclusions At 280 MeV/c the thickness of the radiator has not much influence on imaging 7 Radiator Thickness - G. Gregoire UCL

Non exhaustive ! Very preliminary ! Not optimized Plane mirror Spherical mirror R=-1100 mm Parabolic mirror R curv =-1500 mm  = -1  = 0 Spheroidal mirror R curv = -600 mm along X R curv =-1100 mm along Y More x-focusing obviously needed ! Goal: Č light produced at the focus to get a parallel beam after reflection and placing the detecting plane perpendicularly (for easy simulation/reconstruction)  400 mm mm Focusing - G. Gregoire UCL

700 mm Muons only 700 mm Pixel size 1 mm x 1 mm Losses < Biconic mirror ( not optimized ) 280 MeV/c190 MeV/c The detecting plane does not have to be sensitive over the full area Faint ring due to aberrations … For all muon momenta covered by MICE, For all impact positions and directions at the radiator 135 < Radius of Č rings < 275 mm Full Beam - G. Gregoire UCL

Annular Coverage 270 mm < D < 550 mm 6 Detection Plane - G. Gregoire Just an Example, Not a proposal. Imagine the detection plane is equiped with multianode PMTs like Hamamatsu H7600. H7600 Square PM 26 x 26 mm 16 pixels 4 x 4 mm each Gain stages bialkali 300 < < 600 nm

Nr of photons reaching the detection plane = 89 (for muons of 280 MeV/c) assuming 100% light collection efficiency Average nr of anodes hits = 79 For Cherenkov rings, originating from muons hitting any position on the radiator Geometrical efficiency =89 % 7 Detected Photons from muons - G. Gregoire UCL

Origin = barycenter of the hits Average distances to the center Average (mm)Sigma (mm) muon pion Elementary PID algorithm … without any optimization of the optics !Separation at 3-  level10 Rings - G. Gregoire UCL X Y X = mm ; y = mm P x = MeV/c P y = MeV/c P z = MeV/c

LH n=1.112 (100cm) LH Option Revisited - D. Summers UM

Liquid Nitrogen Cerenkov at BrookhavenUM Phys. Rev. Lett. 4 (1960) 242"In the energy range in which protons of the same momentum had a velocity less than 0.8c, a liquid nitrogen Cerenkov counter was used in place of the gas counter.” Phys. Rev. 125 (1962) 690"For measurement of the pi+ cross section from 450 MeV thru675 MeV, a liquid-nitrogen Cerenkov counter was substitutedfor the gas counter. The index of refraction of liquidnitrogen (n = at its boiling point) was adequate toseparate pions from protons in this energy range.” Tom Devlin Thesis "The counter was constructed quite simply by putting a 6810A phototube with a light tight sealon the neck of a nitrogen dewar. The phototubewas easily removed for checking the level ofnitrogen and filling the Dewar. Although thenitrogen level was kept low enough so that itnever came in physical contact with the phototube,the tube was maintained at very low temperature. This had the desirable effect of a low noise levelin its output. Qualitative checks on the countershowed it to be nearly 100% efficient. Since any inefficiency would have no effect on the cross section, no attempt was made to determine it exactly."

LH Dewar (20degK) Lined or Painted with Diffuse Reflector Vaccuum or Foam Insulation?? ~ 33% Light Collection Efficiency ~ 40 Pe LH Vessel UM 40cm 5” pmt 50cm vacuum Jacket/ super insulation pmt LH 20 o K liner fill tank Quartz vacuum Window + N2 flush Concerns H poisoning H Scintillation

Test Beam PSI/CERN/FNAL/KEK UM/UCL Pmt(s) LN2 77 o K liner Test beam with LN2 radiatior. Basic light collection and uniformity scans can be measured. Test light collection with pipe. Number of PMTs (1-3) Scale to LH Light pipe

UM/UCL team - good synergy. Others welcomed. LN2 Option intrinsically incompatible with ( )  separation for high energy MICE. RICH Option very powerful. Detection plane expensive? PMTs, GEM, MSGC, PWC. Additional manpower needed for RICH development. LH Option intrinsically sound ON-OFF type device. LH vessel/optics presents a challeng with safety issues. Lab assistance and cryo-engineer probably needed. Test Beam in ‘06’ SUMMARY