depfet detectors for future colliders . activities at ific, valencia
DESCRIPTION
DEPFET detectors for future colliders . Activities at IFIC, Valencia. Terceras Jornadas sobre la Participación Española en los Futuros Aceleradores Lineales de Partículas Universitat de Barcelona. Carlos Mariñas, IFIC, CSIC-UVEG. Outlook. - PowerPoint PPT PresentationTRANSCRIPT
C. Mariñas, IFIC, CSIC-UVEG
DEPFET detectors for future colliders. Activities at IFIC,
ValenciaTerceras Jornadas sobre la Participación Española en los Futuros
Aceleradores Lineales de PartículasUniversitat de Barcelona
Carlos Mariñas, IFIC, CSIC-UVEG
C. Mariñas, IFIC, CSIC-UVEG
Outlook
DEPFET: Basics
• General requirements for future colliders• DEPFET: Fundamentals
DEPFET activities at IFIC
• Characterization:• Matrices: PXD4/PXD5/PXD6 production• Single Pixel
• Test Beam• Data analysis
• ILC simulation (see M. Vos talk)• Thermal studies ILC/SuperBelle
• DEPFET thermal mock-up• Simulation
Conclusions
• Pixel detectors for future colliders• IFIC in the DEPFET Collaboration
Vertexing in future collidersC. Mariñas, IFIC, CSIC-UVEG
This requirements impose unprecedented constraints on the detector:• High granularity• Fast read-out• Low material budget• Low power consumption
Vertexing in future colliders requires excellent vertex reconstruction and efficient heavy quark flavour tagging using low momentum tracks
DEPFET Measurements made on realistic DEPFET prototypes have demonstrated that the concept is one of the principal candidates to meet these challenging requirements
C. Mariñas, IFIC, CSIC-UVEG
DEPFET principle
Each pixel is a p-channel FET on a completely depleted bulk
A deep n-implant creates a potential minimum for electrons under the gate (internal gate)
Signal electrons accumulate in the internal gate and modulate the transistor current (400pA/e-)
Accumulated charge can be removed by a clear contact
Fully depleted• Large signal• Fast signal collection
Low capacitance, internal amplification• Low noise
Transistor ON only during readout• Low power
Complete clear• No reset noise Fe
ature
s
C. Mariñas, IFIC, CSIC-UVEG
Introducing the Valencia’s set up
Faraday cage PC for data acquisition Stack of power supplies Laser Motorstages XYZ Complete system for air and
liquid cooling◦ Cooling blocks◦ Aluminium coils
Pulse generator
C. Mariñas, IFIC, CSIC-UVEG
Matrix characterization
Full electrical optimization of matrices: This implies scans over a wide range of the operating voltages to achieve the best signal-to-noise ratio.
• Clear High/Low• Gate ON/OFF• Back• Bulk• Cleargate• Source
Calibration of the system using radioactive sources• Gain of the system• ENC
Laser scans: Charge collection uniformity
C. Mariñas, IFIC, CSIC-UVEG
Already tested at IFIC
CLGClocked CleargateNHE38x30μm2
CCGCommon CleargateLE32x24μm2
C3GCapacitive Coupled Cleargate24x24μm2
ILC design
C. Mariñas, IFIC, CSIC-UVEG
DEPFET Single-pixel (under construction)
D1
D2
SG1
G2Cl
Cl
Clg
Blk
Clg
Inner structure Set-up
Better understanding of new structures• Different geometries (L-
gate)• Implants
Direct access to the system’s parameters• Complete clear• Charge collection• Noise
C. Mariñas, IFIC, CSIC-UVEG
Test Beam
C. Mariñas, IFIC, CSIC-UVEG
Test Beam: Our role
Full electrical characterization of one DUTParticipate in the assembly and allignment of the
telescopeParallel set-up in control roomAnalysis of dataTest Beam Coordinators 2008 and 2009 (M.Vos)
BEAM120 GeV ∏
x
y
z
C. Mariñas, IFIC, CSIC-UVEG
Test Beam: Measurements
Voltage scans: Cross-check optimal settings◦ VBias to the wafer 150-220V◦ VEdge
◦ VClearHigh
Angular scan: Resolution vs. Cluster size◦ -5, -4, -3, -2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 9, 12,
18, 36Beam energy scan: Separation “multi-scattering-
intrinsic resolution”◦ 20, 40, 60, 80, 120 GeV
Large statistics◦ Charge collection uniformity◦ 3 Mevents in nominal conditions
3.5 TB of data20 Million events
C. Mariñas, IFIC, CSIC-UVEG
0 20 40 60 80 100 120 14002468
1012
T.B. Data analysis
d0 (32x24)
d1 (32x24) d2 (24x24) d3* (32x24)
d4 (32x24) d5 (32x24)
Sig3x3(ADU) 1339 1497 1704 1757 1508 1654Noise (ADU) 12,7 13,4 12,7 13,4 12,8 13,2
SNR 105 112 134 131 118 125SeedSignal(A
DU)69% 56% 59% 61% 63% 64%
ENC (e-) 345 326 286 277 309 290gq (pA/e-) 283 316 360 372 319 350
Preliminary
Seed signa
l
Preliminary
Preliminary
Resid
ual (s M
SÅs T
elÅs I
nt, m
m)
Beam Energy (GeV)Distance (mm)
Entri
es
stotal=2,5mm
C. Mariñas, IFIC, CSIC-UVEG
Thermal studies: Simulation and measurements
First DEPFET thermal mock-up
Thermal simulation
C. Mariñas, IFIC, CSIC-UVEG
Thermal measurements Influence of conduction
T of cooling blocks Bump bonding
Influence of convection Air speed Air temperature
Study of new materials
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.252025303540455055606570 Conduction
Liquid 5ºCLiquid 10ºCLiquid 15ºCLiquid 20ºCLiquid 25ºC
Power (W)
Tem
pera
ture
(ºC)
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 727282930313233343536
Convection
Chip's T. Liquid at 15ºC and Air at 22ºCChip's T. NO liquid. Air at 23.5ºC
Air speed (m/s)
Tem
pera
ture
(ºC)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.51
1.52
2.53
3.54
4.5
f(x) = 0.233598089035393 x + 0.0810714543456788
f(x) = 4.24932494364119 x + 0.492739776470649f(x) = NaN x + NaN
Cu. 500 microns.Linear (Cu. 500 microns.)
TPG: k a a-1=4,3 W·mm2/K
Cu: k a a-1=1,1 W·mm2/K
Al: k a a-1=0,2W·mm2/K
DT no
rmal
ized (
K/m
m2 )
Power (W)
New materials
C. Mariñas, IFIC, CSIC-UVEG
Thermal simulation Model implemented in
SolidWorks for future mechanical studies
ANSYS studies calibrated with real data
C. Mariñas, IFIC, CSIC-UVEG
A couple of movies…
Switching mechanism is introduced
Influence of air and liquid cooling studies
C. Mariñas, IFIC, CSIC-UVEG
Conclusions
Vertexing in Future Colliders◦ Very hard conditions
Radiation (10MRad for SuperBelle) Background Reduced material budget Unprecedented granularity Power consumption and heat dissipation
◦ Improvement of the detector’s performance is needed
New generation of pixel detectors try to cope with this requirements
DEPFET: One of the most promising technologies for vertexing and tracking
C. Mariñas, IFIC, CSIC-UVEG
Conclusions: DEPFET in Valencia
Matrix characterization◦ 2 different generations characterized◦ Full electrical optimization◦ Calibration◦ Charge collection uniformity◦ Working on Single Pixel set-up
Test Beam◦ Optimization of DUT◦ Instalation and alignment of the telescope◦ Data analysis
Thermal studies◦ DEPFET thermal mock-up◦ Study of new materials for better cooling◦ Influence of air/liquid cooling◦ Simulation
C. Mariñas, IFIC, CSIC-UVEG
Backup slides
C. Mariñas, IFIC, CSIC-UVEG
Mechanics
1. Support structures:
◦ FEA models of mechanical properties
Natural frequencies Rigidity Stability Deformations
◦ Validation with mock-up
2. Module:
◦ Simulations using FEA: (Finite Element Analysis)
Mechanical effects: Strenght of module Thermal effects: Cooling
◦ Validation with prototypes
C. Mariñas, IFIC, CSIC-UVEG
Competitors for SuperBelle
Strip detecto
rs (DSSD)
•Shorter strips•Fast readout (higher noise)•Cannot be thinnedHybrid
pixel detectors (ATLAS type)
•Good readout speed and granularity•Too much materialPixel
detectors with
frame readout
•High granularity•Low mass (50 microns)•Slow frame readout (rolling shutter)
DEPFET
Discarded
• Material
• Granularity
C. Mariñas, IFIC, CSIC-UVEG
Competitors for ILC
CCD•Small signal•Cryogenic operation•Radiation damage (trapping)
CMOS sensors: MAPS/CAPS•Only small chips possible•Dead material in periphery
Silicon On Insulator (3D integration)•Thick depleted sensor (large signal, fast charge collection)•Only small chips possible•Back-gate effect (depletion voltage couples to FET gate)
C. Mariñas, IFIC, CSIC-UVEG
Double pixel structure
C. Mariñas, IFIC, CSIC-UVEG
Gain and noise
•Ba-133 (30keV g-ray) → 310.4 ADC Units•Cd-109 (22keV g-ray) → 209.9 ADC Units
E (keV)
ADU
22 30
310.4
209.9
FITy=a+bx
Slope=Gainb=12.5 ADC/keV
--
-
ekeVhe
ADCkeVADC 330
106.31
5.12115 3
Noise Gain Energy to
create e-h
C. Mariñas, IFIC, CSIC-UVEG
S/N for a MIP
keVpaireVpairs 80
162.322300
keVm
keVm 12728580450
mm
25.4)133(30)(127
-BakeVMIPkeV
1.- ATLAS supposition: 1 MIP→22300 pairs e-h in 285μm of Si
2.- Our DEPFET has 450μm of Si
3.- The scale factor between Ba-133 30keV g and a MIP is:
)(8625.433.20)133(33.20 MIPNSBaNS ==-=
4.- The S/N of 30keV Ba-133 g ray scaled to a MIP:
C. Mariñas, IFIC, CSIC-UVEG
Noise in current
ADCcountmVVLSB /12.01638412 =
ADCcountnAuA /1.6163841100
nA100~
1.- ADC dynamic range: 2 V – 14 bits ->
2.- trans-impedance amplifier gain = 1 V / 50 mA
3.- 15 ADC counts of noise
C. Mariñas, IFIC, CSIC-UVEG
Introducing the device
Switchers A (Gate) and B (Clear) for CLG
A-GATE B-CLEAR
CURO
C. Mariñas, IFIC, CSIC-UVEG
CLG vs CCG
VCleargate-Low
VCleargate-High
Amp/mV
Time/ms
VClear-High
VClear-Low
Clocked
-
Clearga
te
VCommon-Cleargate
VClear-High
VClear-Low
Common
-
Clearga
te
C. Mariñas, IFIC, CSIC-UVEG
Effect on spectrum
#Ent
ries
ADU
Signal peak
Incomplete
clear
Noise peak
Leackage Current
Background
C. Mariñas, IFIC, CSIC-UVEG
Amplifiers
OUTIN
-5V
1.8V 1.3V-3.2V
-8.2VVsubstr
39kΩ
Iin
AD8015
AD8129
5V 14V
+IN
-IN
REF
FB
>2V
2kΩ 18kΩ
6mV
R10
R10
R50
R5015
0pF
7V
-7V
C. Mariñas, IFIC, CSIC-UVEG
10V
C. Mariñas, IFIC, CSIC-UVEG
drainq Ig
C. Mariñas, IFIC, CSIC-UVEG
Double pixel structure
Actual size of two pixels
Double pixel cell 33 x 47 µm2
C. Mariñas, IFIC, CSIC-UVEG
VDRAIN
VGATE
GND
55Fe
Light
Pulsers Sequencer
Shaper ADC
PC
C. Mariñas, IFIC, CSIC-UVEG
CDS
Correlated Double Sampling Scheme