TOF0 TOF1

Ckov1

IronShield

TOF2Ckov2

Cal

DiffuserProtonAbsorber

IronShield

ISISBeam

•LN2 Option•RICH Option•LH Option

PARTICLE ID - CKOV1 STATUS REPORT UM/UCL

L. Cremaldi, G. Gregoire, D. Summers

CKOV1 = 1/1000 => 3.5-4.0 Acive aperature cm Low energy MICE, 250-300MeV/c MICECapable of measuring beamline purity. Device should exceed >4.0 ??

MICE COLLABORATION MEETING, RAL OCT2005

Beam Profiles at CKOV1 (dated) UM/UCL

Acceptedmuons

Acceptedmuons

r=23cm

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 1.33 1.0 2.0 120 159 22

C6 F14 1.24 1.6 2.7 140 186 18

LN2 1.21 0.81 1.5 158 208 15

LH 1.13 0.071 0,29 202 267 10

Low Index Radiators UM/UCL

240-300 MeV/c•About ~100 pe x 2/3 light collection efficiency ~ 65 pes.•Light Collection Uniformity issues !! •About 4 - 7 degrees of angular separation. Not Used (Ghislain, RICH )

Photo-Electrons Cerenkov Angle

LN2 Radiator for High Momentum UM/UCL

Benchmarck Design for TDR UM

4-MIRROR/PMT DESIGN

• r = 23 cm active aperature

•FC72 Radiator 150-200 MeV/c Z = 5cm

•LN2 Radiator 240-300 MeV/c Z = 10cm

•Light Collection Uniformity needed to be studied.

66 98

pions

muons

280 MeV/c10 cm LN2

240 MeV/c10 cm LN2

38 82

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=scanx=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 <--> 2.2w (x,y)

250MeV/c

y=scanx=0cm

y-cm y-cm

300MeV/c

y=scanx=0cm

~3.2

~2.2

10cm LN210cm LN2Npe

InnerTrack

OuterTrack

OuterTrack

InnerTrack

OuterTrack

OuterTrack

Light Collection Scan 12 Mirror/PMT UM

Npe

~3.2

250MeV/c

y=scanx=0cm

y-cm

10cm LN2

~2.3

y-cm

300MeV/c

y=scanx=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.

InnerTrack

OuterTrack

OuterTrack

InnerTrack

OuterTrack

OuterTrack

LN2 Summary UM

• LN2 + 4- 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 240-300 MeV/c.

Trigger cnt

Light box

Radiator

mu 26o -> 0.450rd --> 4.5 cm/bounce --> 4-5 bounces = 0.94.5 = 62%

pi 18o -> 0.310rd --> 3.1 cm/bounce --> 7-8 bounces = 0.97.5 = 45%

Top view

23cm

50cm --> (2.0 +- 0.2) ns+- 0.2ns slewing

75cm --> (3.0+-0.2)ns +-0.2ns slewing

muonpion

PM

TPM

T

10cm

LN218o 26o

burst

450ps

Timimg off leading 1-2 pe??

TOFC Concept UM

240MeV/c 260MeV/c

280MeV/c 300MeV/c

Timing&Pulse Height Simulation UM

1

1.5

2

2.5

3

3.5

4

230 240 250 260 270 280 290 300 310

PMT First Arrival TIme vs Momentum

P - MeV/c

muons

pions

•Pion signals arrive later and straggle in. •Simulations suggest that witht~ 250ps resolution one mightresolve the mu-pi . •2” pmts needed to collect light. Photonis XP2020 Hamamatsu 5320

0 25ns 0 25ns

X=0. Y=0. cm X=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

12

00

m

mX

Y

Pixel size = 2 x 2 mm2

20-mm thick radiator

( Colors correspond to different particle species )

Sample size:50 k pions

50 k muons

50 k electronsDiam. 250 mm

5

RICH Option - G. Gregoire UCL

Y=0

0.0

200.0

400.0

600.0

800.0

1000.0

1200.0

400 450 500 550X (mm)

Radiator 5 mm

Radiator 20 mm

(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

Rcurv=-1500 mm = -1

= 0

Spheroidal mirror

Rcurv= -600 mm along X

Rcurv=-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

8

12

00

mm

1200 mm

Focusing - G. Gregoire UCL

700 mm

700 mm

Muons only

700 mm

700 mm

Pixel size 1 mm x 1 mm

Losses < 5 10-

4

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 radiator135 < 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 3.5 106 12 stages bialkali 300 < < 600 nm

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100

Nr detected photons

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

-200

-150

-100

-50

0

50

100

150

200

-200 -150 -100 -50 0 50 100 150 200

x (cm)

z (cm)

Muons

Pions

• Origin = barycenter of the hits• Average distances to the center

Average (mm) Sigma (mm)

muon 146.0 12.2

pion 102.2 9.6

Elementary PID algorithm

… without any optimization of the optics !

Separation at 3- level

10

Rings - G. Gregoire UCL

X

YX =-89.88 mm ; y = 35.42 mm

Px = 45.29 MeV/c

Py = 80.42 MeV/c

Pz = 166.08 MeV/c

LH n=1.112 (100cm)

LH Option Revisited - D. Summers UM

Liquid Nitrogen Cerenkov at Brookhaven UM

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 = 1.2053 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

50cm50cm

50cm

vacuumJacket/super insulation

pmt

LH20oK

liner

filltank

Quartz vacuum Window+ N2 flush

Concerns• H poisoning• H Scintillation

Test Beam PSI/CERN/FNAL/KEK UM/UCL

Pmt(s)

LN277oK

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 (3.5-4.0) 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