The progress of TOF Institute of High Energy Physics, Beijing, China
TOF GroupSun Zhijia (sunzj
@mail.ihep.ac.cn) Otc 28, 2006
Outline 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.
Barrel TOF
Endcap TOF
•RICH or Imaging system need more space and money.•CCT has too few photoelectrons to get good time reso.•MRPC is under test.
CsI Calorimete
r
Drift Chambe
r
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
Analysis of Time reso.
Non T
OF
~60ps
Why two layers?
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 ofScin. Totally
100-110ps 110ps-130ps
Two layers,Totally
80-90ps 100ps-110ps
Capability of separation
of Kaon and Pion
MRPC optionbakelite 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 TOF+CCT
Fig. K / separation for Double TOF 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 multi-channel 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
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
Fig. Assembly of barrel TOF.
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.
Mechanical design Connecting design of Barrel TOF
Preamp is directly plugged onto the
breeder board of PMT
HV cable for PMT
LV for preamp
Differential signal
after preamp
Fiber cable for calibration is out of
the Housing.
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
Scitillator Flange of Housing. Its
upper edge is cut to three lines to avoid the
interference of two layers’ flanges.
The housing of Endcap is similar.
The housing of barrel TOF
Binding tests 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
Dark box for R5924-70
light source system
LD
diffuser
fiber
fiber
Bundle of
...
Laser Pulse
Mass Tests @1T by Tokyo U (2)
Relative gain and relative time reso.
By Hamamatsu By Tokyo U
Mass Tests@1T by Tokyo U (3)
0
500
1000
1500
2000
2500
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
1系列
0. 00
20. 00
40. 00
60. 00
80. 00
100. 00
120. 00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
1系列
HV @ gain of 5e5 @1T
Relative time reso. @1T for 500p.e.
Mass Tests by IHEP (1)
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
Dark box
PMT R5924
HV
Signalhousing
LED
fiber
head
Ref. PMT xp2020HV
Signal
Absolute gain at 2000HV
LEDPMT(xp2020)
PMT(R5924)
……
……
……
……
Get the absolute gain of R5924 by measure the SPE.
shield
SPE
background
Mass Tests by IHEP (2)
Absolute gain at 2000HV
The gain by the SPE method is consistent with the manual.
The absolute gain at 2000V is between 5E6 and 2E8
1E7 1E8
1E7
1E8
Ga
in f
rom
SP
E
Gain from Sp/Sk
Gain at 2000V
C
channelpCchannelPeakGain spe
absolute 1910*6.1
/25.0*)(
Rising time of SPE
Rising time vs HV
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.
Dark box
PMTHV
Signalhousing
LED
fiber
head
oscilloscope
shield
Mass Tests by IHEP (3)
Rising time of SPE
1E7 1E8 1E91.5
2.0
2.5
3.0
3.5
4.0
Ris
ing
tim
e (
ns)
Gain at 2000V
Rising time of SPE
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.80
10
20
30
40
50
60
70
80
Data: Data2_CountModel: Gauss Chi^2/DoF = 70.86103R^2 = 0.89727 y0 4.42907 ±2.41529xc 2.31809 ±0.01564w 0.30591 ±0.03438A 27.11498 ±3.0833
Nu
mb
er
Rising time of SPE (ns)
Rising time of SPE
40 50 60 70 80 90 100 110 1201.5
2.0
2.5
3.0
3.5
4.0R
isin
g tim
e (n
s)
Relative time reso. (ps)
Risimg time
The rising time of SPE is about 2.32 +- 0.15 (ns).
Relative time reso.
Rising time: 5.75ns
LED DriverRising time
~1nsWidth ~10ns
Peak ~4V
PMT signal
Mass Tests by IHEP (4)
Relative time reso.
1000000 1E7 1E8 1E940
50
60
70
80
90
100
110
120
Rel
ativ
e tim
e re
so. (
ps)
Gain at 2000V
Relative time reso. VS Gain at 2000V
20 40 60 80 100 1200
10
20
30
40
50
60
Data: Data2_CountModel: Gauss Chi^2/DoF = 20.57839R^2 = 0.88373 y0 0.64231 ±0.93278xc 59.71212 ±0.50038w 14.56323 ±1.12888A 670.77553 ±53.82595N
um
be
r
Relative time reso. (ps)
Relative time reso. by 2000 Npe
50 60 70 80 90 100 110 12030
40
50
60
70
80
90
100
110
120
time
reso
with
out m
agne
tic fi
eld
(ps)
time reso with magnetic field (ps)
time reso (ps)
The relative time reso. is 59.7 +- 7.3 with about 2000 photon electronics.
4.Beam tests and prototype tests
(a) amplitudes of the bar wrapped with different materials
(b) reflectivity of the materials and transmission spectrum of EJ-200
Pakage Atte. length (cm) ESR 400.35.2 Teflon 365.9 4.9Millipore 317.8 6.1Al film 296 .9 8.6Tyvek 290 .2 8.3
Comparison of wrapping materials (Barrel)
Comparison of wrapping materials (Barrel)
Al film is best for barrel, the time reso. can be less than 90ps.
Fig.1 Mirror reflect material
Fig.2 Diffuse reflect material
Simulation on reflectivity
70~80% give better time reso.; consistent with our experiments.
Time reso. Of different Scintillator (Endcap)
BC404 is better than BC408, and their time resolution can be less than 80ps.
Different scintillators
Tyvek and ESR can give similar time reso. But ESR can give bigger signal. So ESR will be used in Endcap.
Various wrapping
Comparison of wrapping materials (Endcap)
Beam tests on TOF protype
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
Preamp Gain :10; rise time <2ns; Integral non-linearity <1% Differential output , noise<20mV; Low power, 0.3W; less
heat in the housing.
0 200 400 600 800 1000 1200 1400 1600
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
Output Signal (mV)
Ris
e T
ime
of P
reA
mpl
ifier
(ns
)
Rise Time of PreAmplifier
PMTPMT信号信号
输入,放大级输入,放大级 输出级输出级
++
--++
--
RRFF
RRSS
输出差分信号输出差分信号AA11
AA22PMTPMT信号信号
输入,放大级输入,放大级 输出级输出级
++
--++
--
RRFF
RRSS
输出差分信号输出差分信号AA11
AA22
Mass production finihed.
VME board: Charge measurement may be a
problem. 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 Signal from PMT is split to
two same signals and each goes to one channel.
The time reso. of FEE <25ps.
PMTOutput
PMTOutput
Tri gger
Sci nti l l atorPMT 5924 PMT 5924 Sp
litt
er
Spli
tter
PMTOutput
PMTOutput
Beam
Del ayCoi nci dence
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)
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
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 TOFItem 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 connectorOf 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
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