E' F' Eikenberry

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PILATUS A 2-D Pixel DetectorFor Protein
Crystallography
E. F. Eikenberry1, Ch. Brönnimann1, S.
Kohout1, B. Schmitt1, G. Huelsen1, H. Toyokawa2,
R. Baur3 and R. Horisberger3 1 Swiss Light
Source, Paul Scherrer Institut, CH-5232
Villigen-PSI 2 SPring8, Japan 3 CMS-Project, Paul
Scherrer Institut, CH-5232 Villigen-PSI
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SLS Layout
Green first phase beamlines Red proposed
beamlines
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X-Ray Diffraction From A ?X-174 Virus Crystal
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Macromolecular Crystallography
Determine the structure of highly complex
molecules to atomic resolution
Molecular Weight gt 1 MDa (gt 50,000 atoms)
Applications
Enzymes Viruses Catalytic mechanisms Electron
transport Energy transduction Motility Drug
Design Structural genomics
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Braggs Law
Diffracted rays
Incident rays
?
?
d
Condition for constructive interference 2d
sin(?) n?
Experimental Setup
Diffracted rays
X-ray beam
Detector plane
2?
Rotating crystal
E. F. Eikenberry
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Using X-ray Diffraction to Determine Molecular
Structure
Structure factors, F(hkl), are given by
where x, y, z coordinates in unit cell,
?(xyz) electron density distribution, h, k,
l coordinates in reciprocal space, and the
integral extends over 1 unit cell
The electron density distribution in the unit
cell, which represents the desired structure, is
obtained by
The observed intensities in the diffraction
pattern are given by
I(hkl) F(hkl)2
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Interpretation
Convolution makes a crystal
X-rays take the Fourier transform of the crystal
The Phase Problem
The pattern is actually x-ray intensity, not the
complex amplitude required to calculate the
desired unit cell structure. Many methods are
used to overcome this.
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• SLS Pixel Detector Goals
• Protein crystallography
• Small Crystals
• Large unit cells
• Energy range 5 - 17.5 keV
• Intensity 1013 x-ray/s on sample
• Spot 15 ?m x 25 ?m
• Divergence 150 ?rad x 30 ?rad
• Rapid tunability
• Fine slicing data collection

• Detector Requirements
• Resolve gt 500 orders
• Large detector area
• Good PSF
• Large dynamic range
• High accuracy
• Fast readout
• Radiation tolerant

E. F. Eikenberry
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The Perfect X-Ray Detector

• Quantum efficiency (at given energy)
• Event rate
• Signal-to-noise
• Linearity
• Saturation
• Dynamic Range
• Detector size
• Spatial resolution
• Energy resolution
• Stability of calibration
• Radiation damage susceptibility
• Ease of use
• Speed Throughput
• Cost

It all depends on the experiment!
E. F. Eikenberry
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Paul Scherrer Institut
The SLS Pixel Detector

• Size 40 x 40 cm2 (0.16m2)
• 2000 x 2000 pixels
• Pixel size 200 x 200 mm2
• Modular detector -gt dead area 6
• High frame rate gt10Hz
• High duty cycle gt94 (Tro6ms)

Base plate (water cooled)
Bank with 5 modules
Tilt angle variable
Modules with 16 chips
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Paul Scherrer Institut
SLS Pixel Module
Ch. Brönnimann, SLS
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Paul Scherrer Institut
Pixel Preamp-Shaper
Ch. Brönnimann, SLS
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Paul Scherrer Institut
Pixel Comparator and trimming

• AC-coupled comparator with diode feedback
• simple inverter as comparator
• comparator biasing done via pn-junction of the
  diode -gt
• expect lower threshold variations on the chip
• radiation insensitive
• low power consumption

Ch. Brönnimann, SLS
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Bump-bonded module See landscape supplement
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SLS Pixel Chip
217 x 217 ?m2 pixels 44 x 78 3432
pixels/chip Chip 10 x 20 mm2 Fabricated in
DMILL 0.8 ?m process 6 wafer yields 64 chips
First batch of wafers had processing defects gt
we dont have to pay gt thats all we have to
work with 0 goodchips 10 to 50 interesting
chips/wafer Left half of wafer is dead in most
cases 2 bad pixels
Second batch of wafers is in hand and being
preprocessed
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Bump-Bonded Module
Indium bump-bonded 8 x 2 chips per sensor Sensor
366 x 157 57,462 pixels Sensor is 8 x 3.6
cm2 Double-size pixels between readout chips
give the sensor continuous coverage
90Sr test - shows almost all pixels good 55Fe
test - shows a range of defects 0 defects (1
chip) 4 defects (1 chip) many defects (most
chips)
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366 x 157 Pixel Module
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Protein Diffraction Pattern See landscape
supplement
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Trimming a Single Chip See landscape supplement
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Trimming A Module With A Global Vcmp
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Threshold vs. Vcmp
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Retrimming A Module
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SLS Detector Architecture See landscape supplement
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SLS 2k ? 2k Pixel Detector
PIXEL 217 ? 217 ?m2 Preamplifier and
shaper Threshold discriminator with 4-bit
trim 15-bit counter gt1 MBq x-ray
rate CHIP CMOS 0.8 ?m DMILL rad-hard Designed
at PSI 44 ? 78 pixels, 9.9 ? 18.3 mm2 Read out
at 10 MHz MODULE Fully depleted diode array 81
? 36.6 mm2 ? 300 ?m, 57,462 pixels Indium
bump-bonded to 16 chips Chips read out in
parallel (5 ms) Module control board BANK 5
modules Bank control board caches
data DETECTOR 12 banks Adjustable
V-shape With fine-slicing, a 180? rotation may
produce 2000 8 MB images (16 GB) in 3 min.
E. F. Eikenberry