R&D program in JFY2002 for JLC vertex detector N.Tamura ; Niigata University Y.Sugimoto, A.Miyamoto...
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Transcript of R&D program in JFY2002 for JLC vertex detector N.Tamura ; Niigata University Y.Sugimoto, A.Miyamoto...
R&D program in JFY2002 for R&D program in JFY2002 for JLC vertex detectorJLC vertex detector
N.Tamura ; Niigata University
Y.Sugimoto, A.Miyamoto ; KEK
T. Aso ; Toyama National College of Maritime Technology
K.Abe ; Tohoku Gakuin Univ.
G.Iwai, K.Fujiwara, H.Takayama ; Niigata University
ContentsContentsI) Design concepts and Requirements
– Accelerator Design– VTX detector design– IR design and backgrounds
II) Present results and Activities– Radiation hardness– Spatial resolution– Fast readout electronics
Summary
AcceleratorAccelerator DesignDesign
6mrad crab crossing
Beam time Structure
Bunch-train Structure
Train = One pulse192 bunches
1.4ns N~1E+10 particles
1/150Hz=6.7ms
Beam profile at IP
243nm
3.0nm dz=110um
I )
VTX DesignVTX Design VTX
– Precise Secondary vertex reconstruction Reconstruct decay vertices of B and D meson decays with excellent b/c
jet separation
– Improvement of momentum resolution Requirements
– Unambiguous 2D reconstruction at high hit density Pixel devices
Expected occupancy in a 20m x 5cm strip detector ~ 100% ! , for hit background rate of about 1hit/mm2/train.
– Less materials (Especially for low momentum tracks) Thin devices Operation at room temperature ~ 0 C -> Simple structure/Easy operation
-> Less thermal distortion of wafers
o
Room temperature operationRoom temperature operation CCDs
– Features Thin/Low-density material Low power consumption But Needs cooling ?
– w/o Cooling system Avoid multiple scattering by
cooling system Avoid thermal distortion of s
ensors ( fabrication – operation temperature discrepancy)
Desirable to operate in room temperature ~ 0 C )
Back-illumination CCD : HPK S7170
Thickness ~20m
CCD Flatness
o
VTX detector designVTX detector design
Baseline design – |cos | < 0.90– Pixel size 25 um– 1.25cm x 5cm x330um– 4Layers with 10deg tilt
( r=24,36,48,60 mm)( Ladder 16/24/32/40)(Sensor 2/3/4/5)
– Intrinsic resolution 4 m(Just for a Simulation input )
1.1824
60
IR Design and BackgroundIR Design and Background
Model d) 3T with SC-QC1
QC1 : Super Conducting magnet L* = 4.3 m To reduce back scattering background produced by the interaction at QC1
R=8~16.5cm
Background estimationBackground estimation Beam-Beam Interaction
– e+e- pair production– Beamstrahlung
Secondary produced backgrounds
R(mm)
TRC(X) 3T *
Preliminary
R(mm)
JLC-A **
JLC-Y**Model b)
VTX1 24 0.77 25 0.36 0.97VTX2 36 0.13VTX3 48 0.10 50 0.42 0.25VTX4 60 0.04 75 0.14 0.11
*Geant4 ( SR/PhotoNuclear )Include solenoid ( uniform 3T ) +QC1 ( Ideal gradient )
Electron backgrounds ( /mm2/train) **Geant3
95bunchesLow Lum.
Similar toTRC(X)
NLC - JLC
Neutrons Previous Study 1E+9/cm2/Yr (Beamstrahlung)
1Yr operation e+e- pair ~1hit/mm2/train1.5E+11/cm2/Yr
Present results and ActivitiesPresent results and ActivitiesRadiation hardnessSpatial resolutionFast readout electronics
II)
Radiation Radiation hardnesshardness
HPK10 HPK10
notch
EEV
Type S5466 CCD02-06
Pixel size [m] 24 22
R/O clock 2-phase 3-pahse
Epitaxial layer[m]
10 20
Notch none 3m none
MPP Operation
Inverted by holes
Si02 – Si Interface
Small packet
Notch CCD 2-Phase CCD 3-Phase CCD
Low density
CCD Structure CCD Structure [cont’d][cont’d]
Result > 1.5E+11e/cm2
JLC: 1.5E+11/cm2/yr @2.4cm
Result > 1.5E+10 n/cm2
JLC: 1E+9/cm2/Yr (Preliminary)
Radiation hardness
Vee (V) Vee (V)
Dark
curr
ent
(ele
ctro
ns/
pix
)
Electrons from 90Sr Neutrons from 252Cf
HPK10
Radiation hardness Radiation hardness [cont’d][cont’d]
Methods VCTI
improvement
3-phase to
2-phase
~2.5 times
Std to
notch structure
~3 or 4 times
CTI properties
3Phase 2Phase
Std
CTI
Notch
VC
TI (
Irr
ad
iati
on
)C
TI (
Irr
adia
tion)
Electron
Neutron
HPK10
CTI~Nt/Ns
Concentration Nt : Defect
Ns : Signal
Radiation test Radiation test -1--1- Our tests showed “Lifetime of CCD > 1Year !
Why additional test of radiation damage, then ?
Non
-Ion
izin
g E
ner g
y L
oss
Radiation damageis thought to be proportional to NIEL
The radiation damageat JLC estimated to be10 times bigger thanour study using 90Sr.
Radiation damage by high energy (>10MeV)electrons should be studied.
Radiation test -1- Radiation test -1- [cont’d][cont’d]
Non
-Ion
izin
g E
ner g
y L
os s
Radiation damage by high energy (>10MeV) electrons
should be studied.
Radiation test (First trial Radiation test (First trial 2002/12/9)2002/12/9)Experimental setup
ElectronBeam150 MeV
Pt 0.1X0
0.5X0
Bending Magnet
Choice of Settings1) Primary Beam Energy
150MeV electrons2) Target radiation length
0.1/0.5 X0
3) B field High/Low Tesla mode
Tohoku-Univ. Lab. of Nuclear Science
Radiation test Radiation test [cont’d][cont’d]
Plan “Trial Run” -> Real Run in May?, 2003
1. Study of Background @LNS CsI(pure) calorimeter2. Irradiation @LNS Energy of electrons On target ; 150 MeV On CCD ; 100 MeV Irradiation: 5x1010/cm2 Dosimetry; RadFET
Radiation test Radiation test [cont’d][cont’d]
Energy distribution of the scattered electrons
Incident electrons: 125 MeV/c
Radiation test Radiation test [cont’d][cont’d]
3. Cryogenic measuring system for CCD - almost same as the one which Stefanov-san used in Japan
Cryostat
Temperature Controller CCD Board inside the cryostat
Spatial resolutionSpatial resolution-Test beam--Test beam-
S/N > 10 @278K
Dark current is suppressed by the successfulOperation of Inverted mode. Noises in a pixel (R/O cycle ~ 3sec. )
HPK10(23e)/ HPK50(58e) / EEV(37e)
HPK50 : HPK with epitaxial layer of 50m
4-Layers CCD Tracker
Spatial resolutionSpatial resolutionTemp.( C)
Method HPK10 HPK50 EEV
-15 C AC 3.56+-0.02 2.67+-0.09 3.71+-0.08
RLM 2.76+-0.03 2.79+-0.09 2.94+-0.10
+5C AC 3.68+-0.03 3.34+-0.10 3.84+-0.08
RLM 3.46+-0.04 3.67+-0.12 2.59+-0.16
RLM : RLM functionAC : Analog centered
PmaxPR =
Pix
el
AP
ixe
l B
Sig
nal
of
Pix
el A
Sig
nal
of
Pix
el B
o
Spatial resolution Spatial resolution [cont’d][cont’d]
Intrinsic ResolutionIs better than 3 m.
Intrinsic ResolutionIs better than 3 m. Thermal diffusion of signal charge improves resolution.
Comparison with simulationComparison with simulation- by T. Aso- by T. Aso
En
ergy
dep
osit
(keV
)
Thickness of active layer(m)
Geant4:Energy Deposit 2GeV,π‐HPK50 12.0keV 7×7clsHPK10
2.2keV 2×2cls
Energy Deposit in Silicon
Estimated Active layer•11m for HPK10•51m for HPK50
Active Active LayerLayer
51.1m
11.0m
HPK10 HPK50
Charge sharing simulation - by T. AsoCharge sharing simulation - by T. Aso
+: d/A=50%×: d/A=30%*: d/A=20%△: d/A=10%□: d/A=5%
Depletion (d)Field Free (f)
Active Active (A=d+f)(A=d+f)
X X
Log(R) Log(R)
d ~ sqrt(2Dt)
f ~ G.R.HopkinsonNIM A216(1983)432 E
ner
gy(k
eV)
N×N Clustering
HPK50
HPK10
Open : Exp
Close : Sim
Drift coff. *Drift Time
Electronics fabricationElectronics fabrication Readout operation
– All pixels must be readout every train crossing interval of 6.7 ms, in the real experiment at JLC.
– 10MHz readout can transfer about 250x250pix in the interval.
5cm
1.25cm
250x250pix/chip16chips/sensor
Total 424 sensors
6784chips needed.
Fast R/O System -1-Fast R/O System -1-Features Fast Not expensive Low power Flexible design
Optical linkLVDS link
1st
2ndFinal
Fast R/O System -2-Fast R/O System -2-Evaluation board of ADC
– CCD Signal processor chip for Digital Camera 9x9mm2 chip size ~ $6/chip
– AD9844A(Analog Devices Co.) 12bit 20MSPS ADC 20MSPS Correlated Double Sampler
6bit variable CDS Gain Amp. Low power consumption(65mW/2.7V)
SHP SHP
SHD
FADC
Fast R/O System -3-Fast R/O System -3-
LVDS Inputs for clocks etc
XC2V404CS144C(FPGA)
AD9844A[FADC]
Backside Interface to Digital board (12 bit DBUS]
Linearity was confirmed.LSB resolution 0.2mV.
Dynamic range 0~800mV
SummarySummary Design and status of JLC VTX detector is presented. Goal --- CCD operation at room temperature
Radiation hardness : No problem, so far.– But, further investigation is necessary.
Electrons => Higher energy must be confirmed experimentally. ( Additional experiments are going. )Neutrons => Yield of neutron is ambiguous ( beam dump ) ( Reliable simulation with precise geometry, JUPITER)
Spatial resolution : < 3m at -15 C.– More investigation of charge sharing property improve resolution?
( Laser scanner test at Niigata Univ. with 2x2m spot.)
Readout Electronics: Evaluating– Study the effect of Fast readout for irradiated samples
Evaluation of thinned device– Partially thinned CCD ..(Distortion measurement system: ready)
o
CCM CCD (1)CCM CCD (1)CCM (Charge carrier multiplier)
– Multiply generated charge using Impact ionization
•Multiplying generated charge directly in the charge domain before conversion into a voltage•High-field region between the two neighboring gates•Gained energy is dissipated through Impact Ionization [II]•Small variance in the II
CCM CCD(2)CCM CCD(2)Difficult to reduce the noise floor of
existing charge detection amplifiers particularly at high clocking freq.
CCM CCD(3) –IMPACTRON-CCM CCD(3) –IMPACTRON- IMPACTRON
– Texas Instruments– TC253SPD– 658(H)x496(V)A
pix. In Image Sensing Area
– 7.4m Square Pixels
– Charge multiplication gain 1~30– Charge conversion
gain w/o CCM 10V/e– Epitaxtial Layer
depth?
690
496
4
500
CCM (400pix)
Charge Multiplication!!!
CCM CCD (4) –CCM CCD (4) –IMPACTRON-IMPACTRON-
Gamma ray spectrum55Fe0 oC
Driver for Impactron is now being developed. ↓
↓ Will be compared withHPK S5466