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Book ChapterDOI

Integrated CMOS sensor technologies for the CLIC tracker

27 Jun 2017-Vol. 213, pp 361-365

TL;DR: CMOS circuitry on a high resistivity epitaxial layer has been studied using the ALICE Investigator test-chip and a Technology Computer Aided Design based simulation chain has been developed to further explore the sensor technology.
Abstract: Integrated technologies are attractive candidates for an all silicon tracker at the proposed future multi-TeV linear \(\mathrm {e^{+} e^{-}}\) collider CLIC. In this context CMOS circuitry on a high resistivity epitaxial layer has been studied using the ALICE Investigator test-chip. Test-beam campaigns have been performed to study the Investigator performance and a Technology Computer Aided Design based simulation chain has been developed to further explore the sensor technology.
Topics: CMOS sensor (53%)

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CLICdp-Conf-2017-011
27 June 2017
Integrated CMOS sensor technologies for the CLIC tracker
M. Munker
1)
On behalf of the CLICdp collaboration
CERN, Switzerland,
University of Bonn, Germany
Abstract
Integrated technologies are attractive candidates for an all silicon tracker at the proposed
future multi-TeV linear e
+
e
collider CLIC. In this context CMOS circuitry on a high res-
istivity epitaxial layer has been studied using the ALICE Investigator test-chip. Test-beam
campaigns have been performed to study the Investigator performance and a Technology
Computer Aided Design based simulation chain has been developed to further explore the
sensor technology.
Talk presented at International Conference on Technology and Instrumentation in Particle Physics 2017
(TIPP2017), Beijing, China, 22-26 May 2017
c
2017 CERN for the benefit of the CLICdp Collaboration.
Reproduction of this article or parts of it is allowed as specified in the CC-BY-4.0 license.
1
magdalena.munker@cern.ch

INTEGRATED CMOS SENSOR
TECHNOLOGIES FOR THE CLIC TRACKER
Magdalena Munker on behalf of the CLICdp collaboration
1
CERN magdalena.munker@cern.ch
2
University of Bonn
Abstract. Integrated technologies are attractive candidates for an all
silicon tracker at the proposed future multi-TeV linear e
+
e
collider
CLIC. In t h is context CMOS circuitry on a high resistivity epitaxial
layer has been studied using the ALICE Investigator test-chip. Test-beam
campaigns have been performed to stu d y the Investigator pe rform a n c e
and a Technology Computer Aided Design based simulation chain has
been developed to further explore the sensor technology.
1 Introduction
The Compact Linear Colli de r (CLIC) is an option for a future linear e
+
e
col-
lider at CERN in the post LHC era, reaching a centre of mass energy up to 3 TeV
[1, 2, 3, 4]. To perform highly precise physics measurements, a single point reso-
lution of 7 µm and a material budget of 1 2%X
0
per layer n ee d to be reached
in the large ar ea tracker detector. To suppress be am induced background par t i -
cles, a time stamping accuracy of 10 ns is required for the main tracker [2, 5].
A large surface ( 100 m
2
) all-silicon tracker is planned to address these require-
ments. Integrated technologies are promising candidates in view of large-scale
production and low material budget. Test beam campaigns to study the Investi-
gator High Resistivity (HR) CMOS test chip have been performed at the CERN
SPS with a 120 GeV pion beam. As a reference system, the CLICdp Timepix3
telescope has been used, providing an excellent tracking and timing resolution
on the Device Under Test (DUT) plane of 2 µm and 1 ns, respectively [6].
2 The Investigator chip
Within the ALICE ITS upgrade project, a fully monolithic chip, the ALPIDE
[7], has been developed in a 180 nm High Resistivity (HR) CMOS process (see
Figure 1). Using the same process, the Investigator test-chip has been developed
[8, 9]. Various pixel layouts are implemented in dierent mini-matrices with
8 8 pixels, to study the impact of the pixel layout on the performance. The
standard p r ocess h as been modified, inserting an additional n-layer (see Figure
2) to create a deep planar pn-ju nc ti on and achieve full lateral depletion of the
sensor. The output of the source foll ower of each individual pixel is connected
to a dedicated output buer with a rise time of 10 ns.

2
P
-
P
++
backside
Deep.P-well
N-well
P-MOS
N-MOS
Fig. 1. Investiga to r standard
process schematic cross section.
N
-
P
Deep'P-well
N-well
P-MOS
N-MOS
Fig. 2. Investigator modified
process schematic cross section.
The outpu t buers are read out by external ADCs, sampling the individual
pixel response with a f r eq ue nc y of 65 MHz [9]. The presented studies have been
performed for a mini -m at ri x with a pixel pitch of 28 µm and a bias voltage of
6 V, using chips with an epitaxial layer thickness of 18 µm for the standard, and
25 µm for the modified process.
3 Test beam data taking and reconstruction
If at least one pixel crosses a seed threshold, the ful l analogue waveform of all
8 8 pix el s is read out. In Figure 3, a typical waveform of a pixel with a particle
hit, as well as the fit function to reconstruct the waveform, are p r ese nted.
Fig. 3. Single pixel waveform reconstructed by a fit of the function f(t).
During the analysis, a threshold is applied on s in gl e pixel level. Since this t h re sh -
old is lower than the seed threshold during data taking, it is referred to as the
neighbour threshold. Adjacent pixe ls with a signal larger than the neighbour
threshold are combined to a clu st e r; and the position is reconstructed by linear
charge interpolati on and -correction. The distan ce be tween the predicted track
position on the Investigator and the reconstructed hit position is require d to be
within 100 µm. Moreove r, tracks passing through the outer half of the edge pixels
are discarded to avoid e.g. eects from the finite track prediction resolution .

3
4 Test-beam results
To explore the charge collection of the modified proc es s in detail, results are
projected onto the predic ted track position within individual pixel cells (in-pixel
presentation). A uniform eciency distribution c an be observed within the pixel
cell (see Figure 4). Fi gur e 5 shows the mean cluster size, defined as the number of
pixels i n a cluster above threshold. As expected from geometrical considerations,
the lowest cluster size is obser ved in the pixel centre. The charge is shared most
likely to one n ei ghb ou r at the pixel edges, and to more than one neighbour at
the pixel corners. As shown in Figure 6, the impact of charge s hari n g is al so
reflected in the distribution of the high es t pixel signal (seed signal) in a cluster:
the more charge is share d between the pixels, the lower the se ed signal.
Fig. 4. Eciency within
the pixel cell.
Fig. 5. Mean cluster size
within the pixel cell.
Fig. 6. Mean seed signal
within the pixel cell.
A global eciency higher than 99 % and a spatial and timing resolution w it h
respect to the reference tracks of 6 µm and 5 ns, respectively, have been
measured. Even though the measur ed timing resolution is limited by the ADC
sampling frequency and the rise time of the output buer, the results are well
within the requirements for the CLIC tracker. In a next phase of R&D the results
on the Investigator test chip will be used to optimise the pixel layout for a fully
integrated chip for the CLIC tracker.
5 Simulation
A simulation chain using GEANT4 [11] to model the energy deposit in the sensor,
a 2-dimen si onal Technology Computer Aided Design (TCAD) [12] simulation to
model the devic e and perform a transient simulation of the charge collection,
and a parametric model to simulate energy fluctuations and to perfor m the
position reconstruction has been developed [13]. The elect r ost at i c potential from
the TCAD simulation is shown in Fi gur e 7 and 8, respectively for the standard
and modified process. As indicated by the white lines, the depletion for the
standard process does extend over the full lateral size of the pixel, whereas the
expected full lateral depletion can be observed for the modified process. Results
are compared between simulation and data in Figure 9 - 11.

4
Fig. 7. Electrostatic potential from
TCAD for the standard process.
Fig. 8. Electrostatic potential from
TCAD for the mo d i ed process.
A comparison of the mean cluster size in the X-direction within the pixel cell is
presented for t he standard process in Figure 9, showing a trend of larger cluster
sizes at the borders of the pixel at 0 and 1 in data, which is well de sc ri bed by
the simulation. For the modified process, an excellent agreement can be observed
between simulation and d at a in the residual distribution in Figur e 10, as well
as in the resolution, defined as the Root Mean Square (RMS) of the residual
distribution, for dierent neighbour thresholds in Figure 11.
Fig. 9. Xclustersizewithin-
pixel cell standard process.
Fig. 10. Spatial residual
modified process.
Fig. 11. Spatial resid-
ual modified process.
6 Summary
The ALICE HR CMOS Investigator test chip has been explored in detail by
in-pixel t es t beam studies and a simulation based on GEANT4 and TCAD.
The simulation results reproduce the te st beam measurements, showing a good
understanding of the technology. An eciency of > 99 % and a spatial and
timing resolution of 6 µm and 5 ns, respectively, have been measured, using a
mini-matrix with a pitch of 28 µm and a bias voltage of 6 V. The measured
performance indic at es the suitability of the technology for the CLIC tracker and
the presented studies are used in a next R&D phase as input for the design of a
fully integrated chip for the CLIC tracker.

Citations
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Book ChapterDOI
Andreas Nürnberg1Institutions (1)
28 Jun 2017
TL;DR: A detector concept meeting the requirements of the proposed future CLIC high-energy linear Open image in new window collider has been developed and an integrated R&D program addressing the challenges is progressing in the areas of ultra-thin sensors and readout ASICs, interconnect technology, mechanical integration and cooling.
Abstract: The physics aims at the proposed future CLIC high-energy linear Open image in new window collider pose challenging demands on the performance of the detector system. In particular the vertex and tracking detectors have to combine precision measurements with robustness against the expected high rates of beam-induced backgrounds. The requirements include ultra-low mass, facilitated by power pulsing and air cooling in the vertex-detector region, small cell sizes and precision hit timing at the few-ns level. A detector concept meeting these requirements has been developed and an integrated R&D program addressing the challenges is progressing in the areas of ultra-thin sensors and readout ASICs, interconnect technology, mechanical integration and cooling.

References
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Journal ArticleDOI
S. Agostinelli1, John Allison2, K. Amako3, J. Apostolakis4  +123 moreInstitutions (34)
Abstract: G eant 4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics.

16,046 citations


Journal Article

6,559 citations


"Integrated CMOS sensor technologies..." refers methods in this paper

  • ...The ALICE HR CMOS Investigator test chip has been explored in detail by in-pixel test beam studies and a simulation based on GEANT4 and TCAD....

    [...]

  • ...A simulation chain using GEANT4 [11] to model the energy deposit in the sensor, a 2-dimensional Technology Computer Aided Design (TCAD) [12] simulation to model the device and perform a transient simulation of the charge collection, and a parametric model to simulate energy fluctuations and to perform the position reconstruction has been developed [13]....

    [...]


DOI
01 Jan 2012
Abstract: This report describes the accelerator studies for a future multi-TeV e+e- collider based on the Compact Linear Collider (CLIC) technology. The CLIC concept as described in the report is based on high gradient normal-conducting accelerating structures where the RF power for the acceleration of the colliding beams is extracted from a high-current Drive Beam that runs parallel with the main linac. The focus of CLIC R&D over the last years has been on addressing a set of key feasibility issues that are essential for proving the fundamental validity of the CLIC concept. The status of these feasibility studies are described and summarized. The report also includes a technical description of the accelerator components and R&D to develop the most important parts and methods, as well as a description of the civil engineering and technical services associated with the installation. Several larger system tests have been performed to validate the two-beam scheme, and of particular importance are the results from the CLIC test facility at CERN (CTF3). Both the machine and detector/physics studies for CLIC have primarily focused on the 3 TeV implementation of CLIC as a benchmark for the CLIC feasibility. This report also includes specific studies for an initial 500 GeV machine, and some discussion of possible intermediate energy stages. The performance and operation issues related to operation at reduced energy compared to the nominal, and considerations of a staged construction program are included in the final part of the report. The CLIC accelerator study is organized as an international collaboration with 43 partners in 22 countries. An associated report describes the physics potential and experiments at CLIC and a shorter report in preparation will focus on the CLIC implementation strategy, together with a plan for the CLIC R&D studies 2012–2016. Critical and important implementation issues such as cost, power and schedule will be addressed there.

470 citations


"Integrated CMOS sensor technologies..." refers background in this paper

  • ...1 Introduction The Compact Linear Collider (CLIC) is an option for a future linear e+e collider at CERN in the post LHC era, reaching a centre of mass energy up to 3TeV [1, 2, 3, 4]....

    [...]


Posted ContentDOI
Abstract: This report describes the physics potential and experiments at a future multi- TeV e+e collider based on the Compact Linear Collider (CLIC) technology The physics scenarios considered include precision measurements of known quantities as well as the discovery potential of physics beyond the Standard Model The report describes the detector performance required at CLIC, taking into account the interaction point environment and especially beaminduced backgrounds Two detector concepts, designed around highly granular calorimeters and based on concepts studied for the International Linear Collider (ILC), are described and used to study the physics reach and potential of such a collider Detector subsystems and the principal engineering challenges are illustrated The overall performance of these CLIC detector concepts is demonstrated by studies of the performance of individual subdetector systems as well as complete simulation studies of six benchmark physics processes These full detector simulation and reconstruction studies include beaminduced backgrounds and physics background processes After optimisation of the detector concepts and adopting the reconstruction algorithms the results show very efficient background rejection and clearly demonstrate the physics potential at CLIC in terms of precision mass and cross section measurements Finally, an overview of future plans of the CLIC detector and physics study is given and a list of key detector R&D topics needed for detectors at CLIC is presented

321 citations


"Integrated CMOS sensor technologies..." refers background or methods in this paper

  • ...1 Introduction The Compact Linear Collider (CLIC) is an option for a future linear e+e collider at CERN in the post LHC era, reaching a centre of mass energy up to 3TeV [1, 2, 3, 4]....

    [...]

  • ...To suppress beam induced background particles, a time stamping accuracy of ⇠ 10 ns is required for the main tracker [2, 5]....

    [...]


DOI
12 Aug 2016
Abstract: The Compact Linear Collider (CLIC) is a multi-TeV high-luminosity linear e+e- collider under development. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in a staged approach with three centre-of-mass energy stages ranging from a few hundred GeV up to 3 TeV. The first stage will focus on precision Standard Model physics, in particular Higgs and top-quark measurements. Subsequent stages will focus on measurements of rare Higgs processes, as well as searches for new physics processes and precision measurements of new states, e.g. states previously discovered at LHC or at CLIC itself. In the 2012 CLIC Conceptual Design Report, a fully optimised 3 TeV collider was presented, while the proposed lower energy stages were not studied to the same level of detail. This report presents an updated baseline staging scenario for CLIC. The scenario is the result of a comprehensive study addressing the performance, cost and power of the CLIC accelerator complex as a function of centre-of-mass energy and it targets optimal physics output based on the current physics landscape. The optimised staging scenario foresees three main centre-of-mass energy stages at 380 GeV, 1.5 TeV and 3 TeV for a full CLIC programme spanning 22 years. For the first stage, an alternative to the CLIC drive beam scheme is presented in which the main linac power is produced using X-band klystrons.

156 citations


"Integrated CMOS sensor technologies..." refers background in this paper

  • ...1 Introduction The Compact Linear Collider (CLIC) is an option for a future linear e+e collider at CERN in the post LHC era, reaching a centre of mass energy up to 3TeV [1, 2, 3, 4]....

    [...]


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