Transcript Document

The progress of TOF
Institute of High Energy Physics, Beijing, China
TOF Group
Sun Zhijia ([email protected])
Otc 28, 2006
Outline
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TOF design
Alignment & mech.
PMT tests
Beam tests and prototype tests
Electronics
Main orders and manufacture
Schedule
1.TOF Design
Options of barrel TOF
The option of barrel TOF is determined after many
discussions in June, 2005. Two layers of scintillator will
be used for barrel.
•RICH or Imaging system need
CsI
more space and money.
Calorimeter
•CCT has too few photoelectrons
to get good time reso.
•MRPC is under test.
Barrel
TOF
Drift
Chamber
Endcap
TOF
Analysis of Time reso.
Non TOF ~
ps
60
Item
Barrel time
reso.
Endcap time
reso.
Intrinsic time reso. of one TOF layer
for 1 GeV muon
80~90 ps
80 ps
Uncertainty from electronics
25 ps
25 ps
Uncertainty from bunch length
15 mm，35
ps
15 mm，35
ps
Uncertainty from bunch time
~20 ps
~20 ps
Uncertainty from Z position
5 mm,25 ps
10 mm,50 ps
Resolution of expected time of flight
30 ps
30 ps
Total time reso, one layer of TOF for
1 GeV muon
100~110 ps
110~120 ps
Total time reso, double layer of TOF
for 1 GeV muon
90 ps
Why two layers?
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Time reso. for Kaon and
pion is worse 20% than
muon in experiences.
Time reso. of two layers
totally is from 100ps to
110ps for kaon and pion.
That time reso. can
separate kaon/pion of
0.9GeV in the middle of
barrel.
Contriburion
Time reso.
For 1GeV
Muon
Time reso.
For
Kaon/pion
Non TOF
60ps
One layer of
scin. Intrinsic
80-90ps
One layer of
Scin. Totally
100-110ps
110ps-130ps
Two layers,
Totally
80-90ps
100ps-110ps
Capability of separation
of Kaon and Pion
MRPC option
bakelite as the resis. plate
Structure:
•Resi. Plate: bakelite
•gaps: 6;
•Chamber: 8cm(W)X190cm(L)
•gas：90%Freon, 5%iso-butane,
5%SF6
•Preamp：Star
Signal pulse
•HV: 16kV/1.2mm)
•Readoud pad:3X6cm
•Rise time:~2ns
•Time Reso.:70～110ps
The results for a MRPC sample where the
fish-line is rolled in longitude direction
MRPC’s option is given up at last.
Candidates
Scintillator MRPC of long
strips
Time reso.
80~90ps
May be less
than 80ps
Price
(No elec.)
3M RMB
1M RMB
Schedule
Ok
Too urgent ;
More R&D
Mechanical
Space
Ok
Ok
Complexity
and stability
Ok
??
Because it is too urgent and need
more R&D on the following three
aspects:
1) bakelite Plate
2) long strip readout
3) stability of running
Also the PID capability will not
improve much if MRPC is used,
because the non-TOF contribute
about 60ps.
Anyway the experiments will go on
in our group.
Cerenkov options
 CCT(Correlated Cerenkov Timing) has
been given up too.
 Its principle is to measure the time of the
cerenkov light to separate particles.
 We did experiments and simulations. There are
too few PEs to get good time reso.
Number of photoelectrons in right or left PMT
versus hit position from CCT simulation.
Comparison of K/ sep.

TOF+TOF
Fig. K / separation for Double TOF

TOF+CCT
Fig. K / separation for TOF+CCT
Potential of CCT:
MCP-PMT to give good time reso.
Refer to:
Jochen Schwiening, SLAC
T. Ohshima, Nagoya Univ.
Cerenkov options
 New DIRC:
 Measure the time and
one-dimension position
 It uses APD or multichannel plate PMT to
measure the time and
position of Cerenkov light
from Quartz.
 No big imaging circles and
so no much space is
needed.
 The money is saved
because of smaller
quantity of PMT.
 This option is under
investigation and may be
used as the upgrade for
BESIII TOF.
2.Alignment and mechanical design
Barrel TOF Dimension
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Banded to MDC outer barrel of
Carbon-fiber
R-direction space: 81cm-92.5cm
Scintillator Length: 2320mm
Coverage:~82%
Pieces: 88 /layer
Thickness: 50mm /layer
Barrel TOF alignment
Fig. BTOF side view. To save
space, the base of PMT
housing is 6-sides-shaped and
the inner and outer layer is
across. It has four screws to
connect the scin.
Fig. Assembly of barrel TOF.
Mechanical design
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Connecting design of Barrel TOF
HV cable for
PMT
Preamp is directly
plugged onto the
breeder board of PMT
Fiber cable for
calibration is out of the
Housing.
LV for
preamp
Differential signal
after preamp
The housing of barrel TOF
Five holes at
corners:
• Four screw holes to fix
up the housing and the
scintillator . Copper
inserts are used.
• The last for fiber
connector
PMT housing
Flange of Housing. Its
upper edge is cut to three
lines to avoid the
interference of two layers’
flanges.
Scitillator
The housing of
Endcap is similar.
Binding tests
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Two layers of barrel TOF will be bound to the MDC carbon
fiber cylinder. Before Al strip was used and it affects the
energy of electron and photon. To decrease the material, the
tape of 3M 898 is planed to be used.
Test is done. Bricks is as the scintillator and the gasolene
bucket is as the MDC cylinder. After 17 days, it is still firm
and stable and no much variation occurs.
brick
The tape
of 3M 898
Gasolene
bucket
Endcap TOF structure
3.Tests on PMT
Mass Tests @1T by Tokyo U (1)
 The magnetic test of each PMT is done by Tokyo Univ.
 Put on and off mag. field 5 times, to see if the PMT can
endure the mag. field up and down.
 Measure the HV at the gain of 5X105 and 1Tesla.
 Measure the relative time resolution of each PMT under 1
Tesla.
Ushikawa
Magnet
Bundle of
diffuser
LD
Laser
Pulse
light source system
fiber
fiber
.
..
Dark box for R5924-70
Mass Tests @1T by Tokyo U (2)
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Relative gain and relative time reso.
By Hamamatsu
By Tokyo U
Mass Tests
@1T by
Tokyo U (3)
2500
2000
1500
系列1
1000
500
HV @ gain of
5e5 @1T
0
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
120.00
100.00
80.00
60.00
Relative time reso.
@1T for 500p.e.
系列1
40.00
20.00
0.00
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21
Mass Tests by IHEP (1)
Dark box
LED
 Each PMT is required to be
checked at IHEP also.
 LED is for the light source
 Four parameters need to be
checked here:
 Relative Gain vs HV
 Absolute gain at 2000HV
 Rising time for single PE
 Relative time reso
head
fiber
Ref. PMT xp2020
HV
HV
PMT
R5924
Signal
housing
Signal
Mass Tests by IHEP (2)
Absolute gain at 2000HV
PMT(xp2020）
LED
PMT(R5924）
shield
…………
…………
SPE
background
Get the absolute
gain of R5924 by
measure the SPE.
Absolute gain at 2000HV
Gain at 2000V
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Gain from SPE
1E8
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1E7
1E7
1E8
Gain from Sp/Sk
Gain
absolute

Peak
spe
( channel ) * 0 . 25 pC / channel
1 . 6 * 10
19
C
The gain by the SPE
method is consistent
with the manual.
The absolute gain at
2000V is between 5E6
and 2E8
Mass Tests by IHEP (3)
Rising time of SPE
Using 1GHz digital oscilloscopes, we get
rising time of SPE of PMTs. It takes about
two hours to test Four PMTs, so we can
measure all the PMTs in about one month.
Rising time vs HV
Dark box
LED
head
shield
fiber
HV
PMT
Signal
housing
oscilloscope
Rising time of SPE
4.0
Rising time of SPE
80
Rising time of SPE
3.5
70
Data: Data2_Count
Model: Gauss
Rising time (ns)
60
Chi^2/DoF
= 70.86103
R^2
= 0.89727
Number
50
y0
xc
w
A
40
4.42907
2.31809
0.30591
27.11498
±2.41529
±0.01564
±0.03438
±3.0833
3.0
2.5
30
2.0
20
1.5
4.0
10
1E7
1E8
1E9
Risimg
time
Gain
at 2000V
0
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.5
3.8
Rising time (ns)
Rising time of SPE (ns)
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The rising time of SPE is about
2.32 +- 0.15 (ns).
3.0
2.5
2.0
1.5
40
50
60
70
80
90
Relative time reso. (ps)
100
110
120
Mass Tests by IHEP (4)
Relative time reso.
Rising time: 5.75ns
PMT signal
LED Driver
Rising time ~1ns
Width ~10ns
Peak ~4V
Relative time reso.
120
Relative time reso. VS Gain at 2000V
110
60
Relative time reso. by 2000 Npe
50
Data: Data2_Count
Model: Gauss
Number
40
30
Relative time reso. (ps)
100
90
80
70
60
Chi^2/DoF
= 20.57839
R^2
= 0.88373
50
y0
xc
w
A
40
0.64231
59.71212
14.56323
670.77553
±0.93278
±0.50038
±1.12888
±53.82595
1000000
1E7
1E8
1E9
Gain at 2000V
120
time reso (ps)
110
10
0
20
40
60
80
Relative time reso. (ps)
100
120
time reso without magnetic field (ps)
20
100
90
80
70
60
50
40
30
50
60
70
80
90
100
time reso with magnetic field (ps)
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The relative time reso. is 59.7 +- 7.3 with about 2000 photon electronics.
110
120
4.Beam tests and prototype tests
Comparison of wrapping
materials (Barrel)
Pakage
ESR
Teflon
Millipore
Al film
Tyvek
Atte. length (cm)
400.35.2
365.9 4.9
317.8 6.1
296 .9 8.6
290 .2 8.3
(a) amplitudes of the bar wrapped
with different materials
(b) reflectivity of the materials and
transmission spectrum of EJ-200
Comparison of wrapping
materials (Barrel)
Fig.1 Mirror reflect material
Fig.2 Diffuse reflect material
Al film is best for barrel, the time reso. can be less
than 90ps.
Simulation on reflectivity
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70~80% give better time reso.;
consistent with our experiments.
Time reso.
Of different Scintillator (Endcap)
Different scintillators
BC404 is better than
BC408, and their time
resolution can be less
than 80ps.
Comparison of wrapping
materials (Endcap)
Various wrapping
Tyvek and ESR can give similar time reso.
But ESR can give bigger signal. So ESR
will be used in Endcap.
Beam tests on TOF protype
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TOF protype includes:
Scin., PMT, Preamp,
18m cable, VME readout
board of FEE
Other systems are
working
The particles are
electron, pion and
proton.
Pion:104±11ps proton:70±2ps
Electron:94±3ps
5.Electronics
Rise Time of PreAmplifier
2.6
2.4
Mass production finihed.
Rise Time of PreAmplifier (ns)
2.2
Preamp
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Gain :10;
rise time <2ns;
Integral non-linearity <1%
Differential output ,
noise<20mV;
Low power, 0.3W; less heat
in the housing.
RF
RS
PMT信号
PMT信号
+
A1
输入，放大级
+
-
A2
输出级
输出差分信号
2
1.8
1.6
1.4
1.2
1
0.8
0
200
400
600
800
1000
Output Signal (mV)
1200
1400
1600
VME board:
Charge measurement may be a problem.
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HPTDC and online
Compensation:
<25ps
Charge-to-Time
Converter: pulse
height measured
by HPTDC
synchronous with
the beam with
jitter lower than
20ps
3Versions:
TOT->VT->QT. The 3rd
Version is under tests.
Time resolution of
Electronics
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Signal from PMT is split to
two same signals and each
goes to one channel.
The time reso. of FEE <25ps.
PMT
Output
PMT
Output
PMT 5924
PMT 5924
Splitter
Scintillator
B
aem
Splitter
PMT
Output
PMT
Output
D
lea
y
Coincidence
Trigger
6. Main orders and manufacture
Main orders and manufacture (1)
 PMT:
 Hamamatsu R5924-70/assy,
525, 17% abundance
 Before March 10, 2006, deliver
 Scintillator:
 Saint-Gobain: BC408 for barrel and BC404 for endcap
 before May 15, 2006 deliver, Now Saint-Gobain says it will be
delayed to August.!!
 Connectors: Having arrived.
 Differential Signal connectors: LEMO
 HV connectors: LEMO 05, special for thin HV cables.
 Preamp input connectors: special made by Suzhou Huaye co. in
China.
 Cables: Having arrived.
 Differential Signal cable: special made by Tianjin Cable co. in
China
 HV cable: Germany Draka cable, type # HTC-50-1-1, specially
made for CERN and DESY.
3. Main orders and manufacture (2)
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Housing of PMT
Special support metal ring needed when
binding TOF onto MDC
Assembly cable and their connectors of HV
and LV
3M tape of 898
Padding material between the two layers of
scintillators
Laser monitor system: fiber, LD, dark box
7. Schedule
Schedule of BESIII
Milestone of BESIII
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2003.3, BEPCII project agreed by Government.
2005.12, MC finished assembly
2006.7~2006.12, Elec., trigger and DAQ
assembly and commissioning
2006.9~2006.11, Joint magnetic field mapping
2006.12~2006.2, EMC barrel installation
2007.2, DC and TOF installation
2007.6~2007.9, Joint commissioning
Schedule of TOF
Item
Time
Remark
PMT Check
06.3.1~06.5.30
At IHEP without magnetic field
LD calibration design and test
06.3.1~06.7.31
By Hawaii Univ.
HV control software development
06.4.1~06.8.31
With Slow Control people
Assembly of cable and connector
Of HV and signal
06.5.1~06.6.30
Scintillator Check
06.6.1~06.8.31(??)
1/e length and relative light output
Manufacture of LD calibration:
06.8.1~07.2.7
Fiber bundle; LD; dark box;
Software etc. by Hawaii Univ.
Check of each channel
(Scintillator+PMT+preamp)
06.9.1~06.11.30
Firstly Match each pair of scintillator and
PMT and preamp; then test its gain and HV.
Prepare for assembly
06.12.1~07.1.7
PMT housing onto scintillator;
Banding Barrel TOF to DC
7.1.8~07.2.8
Assembly of PMT, calbes and LD
calibration
07.2.9~07.3.16
DC is doing similar thing. Need to partition
time or space.
Assembly of Endcap TOF
07.2.15~07.4.15
Together with EMC endcap
Adjusting
07.2.15~07.4.15
Set HV and threshold; noise and PMT
current; LD calibration; electronics and DAQ
Cosmic ray test
07.4.16~07.5.16
8. Summary
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TOF option is determined and the upgrade
to new Cherenkov is under consideration.
Main orders and manufacture have been
finished.
PMT and scintillator meet our requirements.
Prototype test is OK.
Preamp is good and 3rd FEE is under tests !
schedule is OK.
The End