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