Transcript ECFA-Durham, 03 September 2004 CsI(Tl) Calorimeter and status of the E166 experiment E166 experiment CsI(Tl) calorimeter construction. Test beam results vs.

ECFA-Durham, 03 September 2004
CsI(Tl) Calorimeter and status of the
E166 experiment
E166 experiment
CsI(Tl) calorimeter construction.
Test beam results vs. Geant4 simulation
Schedules
conclusion
e+
K. Laihem
Cist) Calorimeter for E166
Overview of E166
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
Experimental Demonstration for production of polarized e+
Final focus test beam (FFTB) at SLAC with 50 GeV electrons
1 m long helical undulator produces circular polarized photons
Undulator radiation 0-10 MeV (Balakin & Mikhailichenko 1979)
Conversion of photons to positrons in 0.5 X0 Ti or W-target
Measurement of polarization of photons and positrons by Compton
transmission method
ECFA-Durham, 03 September 2004
Need for demonstration

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
The production of polarized positrons, depends mainly on the
polarization transfer from polarized photons in the conversion
process (pair production). Fronsdal & Ueberall (1958); Olsen &
Maximon (1959)
In order to understand the experimental difficulties in undulator
based production of polarized positrons we need the
experiment
The design of a linear collider (with or without polarized
positron) may depend on this knowledge
That it sufficient to demonstrate that undulator based
production of polarized positrons works.
ECFA-Durham, 03 September 2004
Photon Transmission Polarimetry

Compton scattering depends on polarization of photon and e-

Either measurement of scattered photons or of
unscattered photons: simpler setup
Trasmission: T L  e  nL phot pair  comp0  e  nLP Pe pol

 


T

T
 Asymmetry:  ( L) 
 nLPe P  Pol


T T

By knowing Pe => P can be calculated:
P 



nL pol Pe A Pe
ECFA-Durham, 03 September 2004
The helical undulator


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
Rotating magnetic field
Wire wound helically
Inner diameter 0.89 mm
(E166)
Magnetic field: 0.76 T (E166)
Pulsed current: 2300 A
Rate 30 Hz (E166)

Parameter
TESLA
E166
Length
~200 m
1m
Beam
~200 GeV
50 GeV
Period
14 mm
2.4 mm
Strength K
1
0.17
Cutoff
~10 MeV
9.6 MeV
Positrons/
bunch
3 x 1010
2 x 107
ECFA-Durham, 03 September 2004
The helical undulator
Cooling system
Pulse Generator
ECFA-Durham, 03 September 2004
Production and Diagnostics of polarized positrons
Two Diagnostic lines
Gamma line
Positron line
Conversion target
Polarized Photons
Polarized Photons
e-
Undulator
50 GeV
Vacuum chamber
SiW Calorimeter
Analyzing magnet
e+
Analyzing magnet
e+
ReConversion
target
e+
e+
ECFA-Durham, 03 September 2004
e+
CsI
Production of Polarized photons
Conversion target
Polarized Photons
Polarized Photons
e-
Undulator
50 GeV
SiW Calorimeter
Analyzing magnet
Polarization
+1
Vacuum chamber
Energy spectrum
e+
Analyzing magnet
e+
ReConversion
target
e+
e+
-1
ECFA-Durham, 03 September 2004
e+
CsI
Production of Polarized positron and Spectrometer
Conversion target
Polarized Photons
Polarized Photons
e-
Undulator
50 GeV
SiW Calorimeter
Analyzing magnet
Vacuum chamber
Polarization / dN/dE
e+
Analyzing magnet
e+
5 MeV 70 %
ReConversion
target
e+
e+
Positron energy (MeV)
ECFA-Durham, 03 September 2004
e+
CsI
Polarization Diagnostics
Conversion target
10 MeV positron on 0.5 X0 W
Polarized Photons
e-
Polarization and counts
Polarized Photons
Undulator
Vacuum chamber
50 GeV
e+
Pol 
5 MeV
Photon energy (MeV)
Analyzing magnet
e+
ReConversion
target
e+
e+
ECFA-Durham, 03 September 2004
SiW Calorimeter
Analyzing magnet
e+
CsI
Polarized Photons
Conversion target
Polarized Photons
e-
Undulator
Vacuum chamber
50 GeV
e+
e+
ReConversion
target
e+
e+
ECFA-Durham, 03 September 2004
e+
CsI
Experimental setup
4x
109
photons
5x106 phE
5 x 104 phE
4 x 109 photons
2 x 107 e+
4 x 107 photons ~ 500 TeV
4 x 105 e+
1.6 x 103 photons of total ~ 6 GeV
ECFA-Durham, 03 September 2004
G1 +
Preamp
Photodiodes
G32 -
G1 +
G1 -
G32 +
Chan 1
Diff Amplifier
G32 +
U-Mass receiver Board
G1 -
Amplifier
Readout electronics
G32 -
60 m
G1 +
Gain 1
ADC
Diode A
G1 G32 +
G32 Diff
Amplifier
Gain 32
G1 +
ADC
Diode B
G1 G32 +
G32 -
CsI Calorimeter Construction
Quality checking
Wrapping the
crystals
Test box and
setup for QC
ECFA-Durham, 03 September 2004
CsI Calorimeter Construction
Quality checking
60 Co
Lead collimator
Diodes
Cist) crystal
6000
6000
5800
5800
Mean at 4746
UC03
5600
5600
5400
5400
5200
5200
3%
4800
4600
3%
4400
Mean at 4898
4%
5000
Yield [Ph/MeV]
Yield [Ph/MeV]
5000
UC08
4200
4000
4800
4600
4400
4000
3800
3800
3600
3600
3400
4%
4200
3400
3200
3200
3000
0
2
4
6
8
10
12
14
16
18
20
22
24
26
Position [cm]
Light yield with respect different position
of the 60 Co source along the Crystal UC03.
ECFA-Durham, 03 September 2004
28
30
3000
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Position [cm]
Light yield with respect different position
of the 60 Co source along the Crystal UC08.
30
CsI calorimeter Construction
Quality checking
Average light yield
at 4600 Ph/MeV
24
7000
UC01
UC02
UC03
UC04
UC05
UC06
UC07
UC08
UC09
22
20
6000
18
Model: Gauss
y=y0 + (A/(w*sqrt(PI/2)))*exp(-2*((x-xc)/w)^2)
±1.63502
0.17776
y0
±38.67729
4672.18296
xc
±116.68723
818.93687
w
19520.17893 ±3700.78059
A
14
Counts
Yield [Ph/MeV]
16
5000
4000
12
10
8
6
3000
4
2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
Position [cm]
28
30
0
2000
2500
3000
3500
4000
4500
5000
Light Yield
Light yield with respect different position
of the 60 Co source all Crystals.
ECFA-Durham, 03 September 2004
Light yield statistics for all 9 Crystals
using 60 Co source.
5500
6000
Cooper foil wrapping and stacking
the 9 crystals inside the brass
housing
Assembling the CsI Calorimeter
ECFA-Durham, 03 September 2004
Test beam in DESZ Hamburg
Calibration/Cobalt source 60 Co
( x )
( x 1.1366  )

2
2
Tall 03 F ( x)  [ax2  bx  c].e dx  A 0.9985.e 2  e 2


2
2




Tall 05
Calibration and Energy Deposition
in the central crystal
Test beam HH July 2004
Central crystal
ECFA-Durham, 03 September 2004
Geant4 one Crystal
Energy deposition
Expo_Gauss Function
1  t   x  x 

0
2 2

 N.e
f (x)  
2
 x x0 
1
  2  
 N.e
x  x0  t
x  x0  t
Transition point (x0+t)
The function and its derivative
are continus at the transition point
Edep In one crystal calorimeter
Correlation between the HG and LG
Xtal08
LG
LG
Xtal03
HG
HG
HG
ECFA-Durham, 03 September 2004
LG
Xtal02
Xtal05
LG
Xtal04
HG
HG
HG
Xtal01
LG
LG
HG
HG
Correlation between the HG and LG
LG
ECFA-Durham, 03 September 2004
LG
Energy Resolution (testbeamHH/MC simulation)
Prototype
testbeam HH
December 2003
0,11
Prototype
CsI Calorimter
Geant4 simulation
0,10
0,09
0,08
TestbeamHH
July 2004
e/Ebeam
0,07
0,06
0,05
0,04
Geant4 simulation
0,03
0,02
0,01
1
2
3
4
Beam Energy (GeV)
ECFA-Durham, 03 September 2004
5
6
Comparison (testbeamHH/MC simulation)
8
1 Crystal (Geant4)
Full Calorimeter (9 Crystals)(Geant4)
Testbeam Hamburg 1 Crystal
Testbeam Hamburg Full Calorimeter
7
6
Edep (GeV)
5
4
3
2
1
0
0
1
2
3
4
5
6
7
Beam
Enegery
(GeV)
Beam
Energy
(GeV)
Edep with respect the beam energy
ECFA-Durham, 03 September 2004
8
Status of
Subcomponents
Component
Helical undulator
Positron transport system
Status
Institution
2x 1 m Ready (Tested)
(soon at SLAC)
In construction
„Cornell University“
„Princeton University“
Analyzer magnets
Ready (Tested)
(In installation at SLAC)
„DESY Hamburg“
CsI calorimeter
Ready (Tested)
(In installation at SLAC)
„DESY Zeuthen/ Humboldt
University Berlin
Si-W calorimeter
Ready (Tested)
(In installation at SLAC)
„University of Tennessee“
Aerogel counters
Ready (Tested)
(soon SLAC)
DAQ and Readout
Ready (Tested)
(In installation at SLAC)
ECFA-Durham, 03 September 2004
„Princeton University“
„SLAC“
Conclusions.
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E166 is a demonstration of production of
polarized positrons for future linear colliders
Uses the 50 GeV FFTB at SLAC
All prototypes work properly
Installation of total experiment in FFTB tunnel in
September 2004
First data taking run in October 2004
Second data taking in January 2005
Geant4 simulation of the full E166 spectrometer
Implementation of the linear polarization and polarization transfer in Geant4
Data analysis starting with the E166 experiment October 04 April 05
First published results by the end of next year
ECFA-Durham, 03 September 2004