super belle cdc basic design electronics test of pre-amplifier chips wire stringing method schedule...
TRANSCRIPT
Super Belle CDC
Basic design Electronics
Test of pre-amplifier chips
Wire stringing method Schedule
Shoji Uno (KEK)
Dec-12th, 2008
Baseline Design
Belle
sBelle
Main parameters
Present FutureRadius of inner boundary (mm) 77 160Radius of outer boundary (mm) 880 1140Radius of inner most sense wire (mm) 88 172Radius of outer most sense wire (mm) 863 1120Number of layers 50 58Number of total sense wires 8400 15104Effective radius of dE/dx measurement (mm) 752 978Gas He-C2H6 He-C2H6
Diameter of sense wire (m) 30 30
1200 mm
250
mm
250
mm
Present CDC
New CDC
Wire Configuration
Yesterday CDC meeting
One and half hours from 16:00 Main topics
Test results of pre-amplifier chips Wire stringing method
Several new people joined. One new KEK posdoc candidate 3 persons from KEK electronics group 5 foreigners One Japanese person (non current CDC member) 3 current CDC KEK members 13 in total : more than I expected.
We are waiting for more people.
Prototype of readout board by Y. Igarashi
Under 20cm
ASB +Discriminator
ASB +Discriminator
ASB +Discriminator
ASB +Discriminator
FADC
16ch/board BJT-ASB/Comparator part FADC: over 20MHz / 10bit FPGA : Vertex-5 LXT
TDC: 1 nsec counting FADC reading Control
FPGA: Spertan3A SiTCP
RJ-45 for SiTCP RJ-45 for Belle DAQ timing signal
s SFP for Belle DAQ data line LEMO input x 3 LEMO output x1 Shielded substrate
FPGA(CONTROL,
TDC)R
J45
RJ4
5
SF
PO
ptic
al T
rans
ceiv
er
FADC
FPGA(SiTCP)
Test of Amplifier by N. Taniguchi
Three amplifiers Hybrid pre-amplifier (with receiver, gain:10) used in Belle-CDC ASD ( Amp + Shaper + Discriminator ) chip (with receiver, gain:7 ) used in ATLAS-TSC
No production, now.
ASB ( Amp + Shaper + Buffer ) developed by ASIC group of KEK Can be optimized for Super Belle CDC in near future.
Check signal shape using oscilloscope
Gas (Ar 90%+CH4 10%)
Tungsten wire
Fe55 5.9keV X-ray
Small tube chamber
Amp Receiver
Comparison HV=1.7kV
~220mV
~140mV
T-ASD
ATLAS ASD
40ns
HV [kV]
Puls
e h
eig
ht
[mV
] ● Belle AMP■ ATLAS ASD▲ T-ASD
100ns
40ns
Belle AMP
~300mV
~5mV
ATLAS ASD
Comparison
~5mV
Belle AMP
~3mV
T-ASD
HV=1.9kV
~600mV
distorted
HV=1.9kV
~600mV
saturate
T-ASDATLAS ASD
Noise level
Saturation
Results on test of amplifiers
New ASIC chip is usable after some modifications.
We can contact KEK electronics group closely.
Wire stringing
Now, I am thinking a vertical stringing, not horizontal. Once, I thought the horizontal stringing.
Vertical stringing with outer cylinder.Human can stand inside the chamber and can touch
the wire. Inner diameter without the small cell part : ~500mm Inner diameter of present transition cylinder : 580mm
Stringing with tension can be done from outer layer.Two-way method ( Belle-CDC ) is not necessary.
Discussion with technical stuffs
We just started discussion with KEK technical stuffs. Calculation of deformation and stress Support method etc
Need more man power.
My Personal Plan for Construction
Backup Slides
Hit rate
10kHz
Apr.-5th ,2005IHER = 1.24AILER = 1.7ALpeak = 1.5x1034cm-2sec-1
ICDC = 1mA
Main
Inner
Small cell
200kHz×20
Hit rate at layer 35 410I**2 + 1400*I + 80
0
200
400
600
800
1000
1200
1400
1600
0 0.2 0.4 0.6 0.8 1
HER Beam Current(A)
Hit
rat
e(H
z)
740I**2 + 470*I + 80
0
500
1000
1500
2000
2500
3000
0 0.5 1 1.5 2
LER Beam Current(A)H
it R
ate
(Hz)
IHER = 4.1A Hit rate = 13kHzILER = 9.4A Hit rate = 70kHz
Dec., 2003 : ~5kHzNow : ~4kHz
Dec.,2003
In total 83kHz
HER LER
Simulation Study for Higher Beam Background
by K.Senyo.
MC +BGx1 MC+BGx20
Jan24-26, 2008 BNM2008 Atami, Japan 18
BG effect on analysis
Major loss come from low tracking efficiency on slow particles. Efficiency loss on high multiplicity event is serious. Pulse shape information by FADC readout can save efficiency. SVT standalone tracker will be a great help (not included in this study).
B Eff Ratio-1
Nominal 56.8 % 0.0 %
×5 BG 56.0 % -1.5 %
×20 BG 49.0 % -13.8 %
With 40% shorter shaping
×20 BG 51.4 % -9.5 %
)()( SK/J )( 3KD,DDDD s***
B Eff Ratio-1
Nominal 6.48 0.0 %
×5 BG 5.69 -12.2 %
×20 BG 2.28 -64.9 %
With 40% shorter shaping
×20 BG 3.86 -40.5 %
By H.Ozaki Preliminary
Talk by T. Kawasaki
Background effect on tracking
19
)( 3KD,DDDD s***
Many low momentum tracks, the hardest case for tracking
Gain in reconstruction efficiency of BD*D*
H. OzakiBNM2008
Excellent with help of SVDExcellent with help of SVD
Idea for upgrade In order to reduce occupancy,
Smaller cell sizeA new small cell drift chamber was constructed and installed. It has been working, well.
Faster drift velocityOne candidate : 100% CH4
Results show worse spatial resolution due to a large Lorentz angle.
A beam test was carried out under 1.5T magnetic field.So far, no other good candidate.
Small Cell Drift Chamber
Photo of small cell chamber
Installation in 2003 summerJust after wire stringing
XT Curve & Max. Drift Time
Small cell(5.4mm)Normal cell(17.3mm)
Chamber Radius
Inner radius Physics : Vertexing efficiency using Ks SVD determines the boundary. At present, the boundary is 15cm in radius.
Outer radius New barrel PID device determines the outer radius. At present, 115cm is selected, tentatively.
The boundary condition is important to start construction. Basically, CDC can manage any radius.
Wire configuration 1
Super-layer structure 6 layers for each super-layer
at least 5 layers are required for track reconstruction. Even number is preferred for preamp arrangement on
support board to shorten signal cable between feed-through and preamp.
Additional two layers in inner most super-layer and outer super-most layer. Higher hit rate in a few layers near wall. Inner most layer and outer most layer are consider as
active guard wire.
Wire configuration 2
9 super-layers : 5 axial + 4 stereo(2U+2V)A 160*8, U 160*6, A 192*6, V 224*6, A 256*6, U 288*6, A 320*6, V 352*6, A 388*8
Number of layers : 58 Number of total sense wires : 15104 Number of total wires : ~60000
Deformation of endplate
Number of wires increase by factor 2. Larger deformation of endplate is expected. It may cause troubles in a wire stringing process and other occasions.
Number of holes increases, but a chamber radius also enlarges. Cell size is changing as a function of radius to reduce number of wires. The fraction of holes respect to total area is not so different, as comparing
with the present CDC.11.7% for present CDC12.6% for Super-Belle CDC
In order to reduce deformation of endplates, The endplate with a different shape is considered. Wire tension of field wires will be reduced.
Anyway, we can arrange the wire configuration and can make a thin aluminum endplate.
Expected performance
OccupancyHit rate : ~100kHz ~5Hz X 20 Maximum drift time : 80-300nsec Occupancy : 1-3% 100kHz X 80-300nsec = 0.01-0.03
Momemtum resolution(SVD+CDC) Pt/Pt = 0.19Pt 0.30/[%] : Conservative Pt/Pt = 0.11Pt 0.30/[%] : Possible 0.19*(863/1118)2
Energy loss measurement 6.9% : Conservative6.4% : Possible 6.9*(752/869)1/2
About readout electronics
At present, S/QT + multi-hit TDCS/QT : Q to Time conversionFASTBUS TDC was replaced with pipeline COPPER TDC.
Three options, High speed FADC(>200MHz) Pipeline TDC + Slow FADC(~20MHz) ASD chip + TMC(or new TDC using FPGA) + slow FADC near det
ector. ASIC group of KEK Detector Technology Project is developing new AS
D chip. New TDC using FPGA is one candidate for TDC near detector.
Summary
When Belle group decides the upgrade plan, we can start construction of the new chamber soon. It takes three years to construct the chamber.
Outer radius( and inner radius) should be fixed as soon as possible.Barrel PID determines the schedule. Inner radius should be determined by SVD.Supporting structure should be discussed.
One big worry is man power. I hope many people join us when the upgrade plan starts.
Radiation Damage Test
a: ’93 Plastic tube d: ’94 SUS tubeb: ’93 Plastic tube + O2 filter e: ’94 SUS tube + O2 filterc: ’94 Plastic tube f: ’94 Plastic tube
Total accumulated charge on sense wire(C/cm)
Gai
n de
grad
atio
n
Test chamber and beam test
A test chamber with new cell structure was constructed.Part of inner most 20 layer( 8 layers with small cell + 12 layers with
normal cell)
A beam test was carried out in the beginning of June at 2 beam line of 12GeV PS.We confirmed the simulation for pure CH4 is correct. Velocity under
1.5T is not faster than the present gas and the drift line is largely distorted due to larger Lorentz angle.
Similar performance could be obtained using new S/QT module with less dead time.
Many data were taken using 500MHz FADC, which was developed by KEK electronics group. Now, a student is analyzing data. We hope to get information about minimum necessary sampling speed for timing and dE/dx measurement.
xt curve for new gas(7mm cell)
Distance from wire (cm)
Pure CH4
100nsec
Distance from wire (cm)
Dri
ft ti
me
(se
c)
Dri
ft ti
me
(se
c )
He/C2H6 = 50/50
100nsec
Drift Velocity
Two candidate gases were tested. CH4 and He-CF4
In case of He-CF4, higher electric field is necessary to get fast drift velocity.
In case of CH4, faster drift
velocity by factor two or more can be obtained, even in rather lower electric field.
dE/dx Resolution
The pulse heights for electron tracks from 90Sr were measured for various gases.
The resolutions for CH4
and He(50%)-C2H6(50%) are same.
The resolution for He-CF
4 is worse than Ar-based
gas(P-10).
Wire chamber
Wire chamber is a good device for the central tracker. Less material Good momentum resolution. Cheap It is easy to cover a large region. Established technology Relatively easier construction. Many layers Provide trigger signals and particle
ID information.
Wire chamber can survive at Super-KEKB. Our answer does not change after the last WS in
2004. The beam background became smaller even for higher beam
current and higher luminosity. We recognize the luminosity term is small, clearly.
CDC Total Current Maximum current is
still below 1.2mA, even for higher stored current and higher luminosity.
Vacuum condition is still improving. Thanks KEKB people for
hard work. I hope there is still room
to improve vacuum condition further.
Luminosity Dependences
CDC BG did not change!
Feb, 2004
Inner most
Middle
Outer
Occupancy
Luminosity
1034cm-2sec-1
No. of channel
NTotal
Readout time
(sec)
Q>0 Q>50
NHit
Belle 1.5 8464 6 - 300
Babar 0.8 7104 2 ~700 ~350
Occ. = NHit/NTotal
(%)
Occ./Time
(%/sec)
Max. drift time
(sec)
Occ./Time x Max. Drift time (%)
Normalized by Lum.(%)
Belle 3.5 0.58 0.4 0.23 0.15
Babar 4.9 2.45 ~0.6 1.47 1.84
x20 Bkgd in Belle CDC ~ x3 Bkgd in Babar DCH
Random trigger
at HL6 in KEK
Curved Endplate
Deformation of endplate due to wire tension was calculated at design stage of present Belle CDC (Total tension: 3.5 Ton).
Deformation(mm) 35.2 2.03 1.31
Present New
Weight
Endplate Al, Thickness : 10mm (12mm) 110kgx2 = 220kg (264kg)
Outer Cylinder CRRP, Thickness : 5mm 210kg
Electronics Board G10, 48ch/board 0.3kgx315 = 95kg
Present support
Calculation of deformation and etc
Deformation of Aluminum endplateThickness of endplate 10mm 12mm
Deformation 1/t3 1 0.58Tension of field wire 120g 80g
Gravitational sag, Sense : 120m(80g), Field:300m(80g)Total tension 4.8ton
Stress calculation Thickness of outer cylinder CFRP : mm Transition structure between endplate and outer cylinder
Support structure Structure for wiring jig
Simpler one as compared with Belle-CDC
Etc.
Installation Removing and installation
can be done using similar small bar in horizontal direction.
Cathode installation in vertical direction CDC installation in horizontal direction
Signal Shape
Each signal shapes are not same.
Rise time : ~10sec Pulse width : ~200nsec. Maximum drift time :
~300nsec
Timing resolution
Good timing resolution for the drift time measurement is key item.
250MHz sampling is not good enough.Present leading edge
measurement shows 130m resolution.
1nsec resolution is required.
0100200300
400500600700
0 10 20 30 40
Sampling width (nsec)
Spat
ial r
esol
utio
n (
m)
Before correction
After correction
FADC test
Sampling rate for energy loss measurement
Slow sampling rate is good enough for energy loss measurement.
20MHz is OK. ns0
2
4
6
8
10
12
0 100 200 300
1/ Tサンプリングレート( )
%分解
能()
Sampling width (nsec)
dE/d
x R
esol
utio
n m
easu
rem
ent (
%)
Purposes of the Readout board Prototype
A study of the CDC readout schemeCharge measurements by FADCDrift time measurements by FPGA base TDC
A evaluation of ASB for CDC readout A study of the noise diffusion from the
readout board to CDC We hope to study about CDAQ/Front-end
data transport.
ASB part diagram
ASB Amp. Shaper Buffer 4ch/chip Gain :
-360mV/pC ~ -1400mV/pC (4 step variable)
Power consumption : ~18mA
LOGIC part diagram
FADCTi
ADS5287
ASBDiscriminator
SFP(Optical connector)
RJ-45
LVDS8 pairs
CONTROL 3x4
Vertex-5 LXT(XC5VLX50T, IO:360pin)
LVDS 2 pairs
LVDS 4 pairs
RJ-4515
TIMING LVDS 4x4 pairs
LEMO
LEMO
LEMO
LEMO
RocketIOGFP
100basePHY
Spertan3ASiTCP
TDC(with FIFO)
3
FIFO
4 LEDDIP-SW8
16
16
TEST PIN16
CONTROL
CLK125MHz
Sampling CLK20~40 MHz
CLK42.33MHz
ASBDiscriminator
FADCTi
ADS5287
ASBDiscriminator
ASBDiscriminator
De-
seria
lizer5
LVDS8 pairs
5
48
DIP-SW
TEST PIN8
32
CLK50MHz
LVDSCLKs
LVDSCLKs
PUSHSW
DAC(Vth)
8
RocketIOGFP
SFP(Optical connector)
LVDS 2 pairs
CLKFor GFP
Schedule plan
2008/11 Specification design
2008/11,12design and drawing the circuit
ASD part (T.Taniguchi-san)Digital part (M.Saito-san)
2008/12 end order the substrate
2009/2 Check the mask patternM.Ikeno-san etc…
2009/3 Start the practical study
Introduction
ATLAS-ASD Pre gain 0.8 V/pC , main x 7
Fe55
Fe55
T-ASD (Taniguchi-san, ASIC group) ~ 7V/pC
ASD buffer
Conclusion
Gain : T-ASD is smaller (0.6 x ATLAS ASD, half of Belle AMP)
Noise level: T-ASD is smaller Resolution : T-ASD seems to
be better than ATLAS ASD Rise time is ~ 20 ns for ATLAS
ASD and T-ASD Saturation : ~ 1.9kV
Beam test using test chamber and new ASIC chip ~ Apr, 2009
ATLAS ASD
HV=1.6kV HV=1.7kV
HV=1.8kV
~80mV
40ns
~220mV
~500mV
HV=1.9kV
~600mV
distorted
T-ASD
HV=1.6kV HV=1.7kV
HV=1.8kV HV=1.9kV
~50mV ~140mV
~300mV
~600mV
40ns
saturate
Belle AMP (HV=1.8kV)