Charged kaon identification system for the CMD3 detector - - PDF document

Charged kaon identification system

Maxim Nikulin

for the CMD–3 detector

VEPP-2000 e+e− collider at the Budker Institute of Nuclear Physics Novosibirsk, Russia CMD–3 magnetic general purpose detector

• ✁

• ❍

drift chamber magnetic lenses VEPP−2000 SC 25 900 Z−chamber/ BGO calorimeter superconducting solenoid R300 LXe calorimeter CsI calorimeter iron yoke PID

1 June 2004

• M. Nikulin CMD–3 PID

VEPP-2000 Parameters

Maximum beam energy 1.0 GeV Luminosity 1032 cm−2s−1 Bunch dimensions

125 µm × 4 cm length

Particles per bunch 16 × 1010 Bunches per ring 1 e+ and 1 e− Average beam current 300 mA each Circumference 24 m (80 nsec period) Interaction regions 2 (CMD–3 and SND detectors)

Physics program

• Precise measurements of e+e− annihilation cross section into hadrons

(for variety of dispersion calculations, e.g. vacuum polarization and muon anomalous magnetic moment)

• QCD at low energy
• Study of ρ, ω, ϕ excitations, their parameters measurement

2 June 2004

• M. Nikulin CMD–3 PID

PID variant Scintillation time of flight counters

p, MeV/c 200 400 600 800 1000 p, MeV/c 200 400 600 800 1000 TOF, nsec 0.8 1.0 1.2 1.4 1.6 1.8 2.0 p, MeV/c 200 400 600 800 1000 p, MeV/c 200 400 600 800 1000 TOF, nsec 0.8 1.0 1.2 1.4 1.6 1.8 2.0 e µ π K = 75 psec

TOF

σ

TOF for different types of particles if their direction is perpendicular to the beam axis. Geant4 simulation results

Time, ns 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5

Integral 313.5

Time, ns 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5

p.e.

N 1 2 3 4 5 6 7

Integral 313.5

Time, ns 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5

Integral 313.5

Time, ns 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5

p.e.

N 1 2 3 4 5 6 7

Integral 313.5

Distribution of the photons arrival time to the PMT 800 × 40 × 2 mm3 BC-404 scintillator slabs (48 total).

3 June 2004

• M. Nikulin CMD–3 PID

PID variant Aerogel Cherenkov counters with wavelength shifters

ASHIPH type, like in the KEDR detector (M.Yu. Barnykov et al. Nucl. Instrum. Meth. A419: 584-589, 1998) 64 counters (2 along z and 32 ϕ-sectors)

MCP PMT 58 (11,2 ) 2 400 WLS BBQ PTFE 400µ m reflector aerogel n = 1.13

Light collection efficiency simulation results Minimal photoelectron number

c , MeV/ p 300 400 500 600 700 800 900 1000 c , MeV/ p 300 400 500 600 700 800 900 1000

p.e.

N 1 2 3 4 5 1000 MeV =

K

E π K

Probability (W) to pass through a wavelength shifter (identification inefficiency) p, MeV/c θ, ◦ W % 850 90 6,7 400 45 10,0

4 June 2004

• M. Nikulin CMD–3 PID

PID variant Cherenkov correlated timing technique

(K. Honscheid et al. Nucl. Instrum. Meth. A343:306-310, 1994) Principles

∆ l

• ✁

π K particle charged MCP PMT quartz slab θ

Slab thickness 7 mm. Simulation results

t, nsec 2.5 3.0 3.5

π K

p, MeV/c 200 400 600 800 p, MeV/c 200 400 600 800

p.e.

N 5 10 15 20 π K

θ = 60◦

5 June 2004

• M. Nikulin CMD–3 PID

Tests of microchannel plate photomultipliers

Cosmic ray muons produce Cherenkov light in the quartz plates. Pulses form PMT’s start and stop the time to digital converter.

MCP PMTs quartz plates aluminum backed mylar and teflon wrap

• Ch. for 20 mm, CDC counts

500 1000

• Ch. for 20 mm, CDC counts

500 1000 Charge for 10 mm 100 200 300 400 500 600

• Ch. for 20 mm, CDC counts

500 1000

• Ch. for 20 mm, CDC counts

500 1000 Charge for 10 mm 100 200 300 400 500 600 TDC counts (62 ps)

• 5 0

5 10 15 20 25 TDC counts (62 ps)

• 5 0

5 10 15 20 25 Events 20 40 60 80 100 120 140 160 TDC counts (62 ps)

• 5 0

5 10 15 20 25 TDC counts (62 ps)

• 5 0

5 10 15 20 25 Events 20 40 60 80 100 120 140 160 Clbr Raw Corrected = 1.03 σ

Timewalk correction

Charge, CDC channels 200 400 600 800 1000 1200 Charge, CDC channels 200 400 600 800 1000 1200 , ps

2

• t

1

t

• 600
• 400
• 200

200 400

p.e.

N 50 100 150 200 250 < 800

2

) for 550 < c

1

dt(c < 400

1

) for 250 < c

2

dt(c

6 June 2004

• M. Nikulin CMD–3 PID

Conclusion

• 3 PID variants are considered: TOF, ASHIPH (aerogel), CCT (quartz)
• ASHIPH: performed simulation of light collection efficiency
• TOF and CCT: simulation — photon arrival time distributions
• MCP PMT tests: resolution of about 60 psec obtained with quartz plates

having thickness of 3–20 mm and scintillator samples

Plans

Simulation

• Electronic response for TOF and CCT
• δ-electrons contribution for ASHIPH and CCT

Tests

• MCP PMT resolution with Cherenkov light radiating in the PMT window
• TOF prototype
• Electronics developing and optimization

7 June 2004

• M. Nikulin CMD–3 PID