The proposed Circular Electron Positron Collider (CEPC) imposes new challenges for the vertex detector in terms of high resolution, low material, fast readout and low power. The Monolithic Active ...Pixel Sensor (MAPS) technology has been chosen as one of the most promising candidates to satisfy these requirements. A MAPS prototype, called TaichuPix1, based on a data-driven structure, together with a column drain readout architecture, benefiting from the ALPIDE and FE-I3 approaches, has been implemented to achieve fast readout. This paper presents the overall architecture of TaichuPix1, the experimental characterization of the FE-I3-like matrix, the threshold dispersion, the noise distribution of the pixels and verifies the charge collection mechanism using a radioactive source. These results prove that the digital periphery and serializer are able to transmit the collected charge to the data interface correctly. Moreover, the individual self-tests of the serializer verify that it can work up to about 3 Gbps, while they also indicate that the analog front-end features a fast-rising signal with a short time walk and that the FE-I3-like in-pixel digital logic is properly operating at the 40 MHz system clock.
The performances of Low Gain Avalanche Diode (LGAD) sensors from a neutron irradiation campaign with fluences of 0.8 נ1015, 1.5 נ1015 and 2.5 נ1015 n eq/cm2 are reported in this article. These LGAD ...sensors are developed by the Institute of High Energy Physics, Chinese Academy of Sciences and the Novel Device Laboratory for the High Granularity Timing Detector of the High Luminosity Large Hadron Collider. The timing resolution and collected charge of the LGAD sensors were measured with electrons from a beta source. After irradiation with a fluence of 2.5 נ1015 n eq/cm2, the collected charge decreases from 40 fC to 7 fC, the signal-to-noise ratio deteriorates from 48 to 12, and the timing resolution increases from 29 ps to 39 ps.
CMOS Pixel Sensors (CPS) are attractive for CEPC vertex detector construction due to its high granularity, high speed, low material budgets, low power and potential high radiation tolerance. The ...characteristics of the sensing diode and the readout architecture were studied using several chips with small-scaled pixel array for CEPC vertex detector. This paper will study the design of a high data-rate readout logic design of a 512×1024 pixel array. For the innermost layer of CEPC vertex detector, the hit pixel frequency is near 120 MHz, which is several times higher than the design requirements of ALPIDE for ALICE vertex detector. Based on the hit-driven readout scheme in the pixel array of ALPIDE and FEI3, we propose a new peripheral readout logic design. All the double columns of pixels are read out in parallel and a fast readout architecrue of 512 double columns is realized. Meanwhile, a real-time data compression and a trigger-mode operation are supported to reduce the data output. The simulation results indicate the pixel hit frequency in average of 120 MHz can be processed with readout time of 50 ns per pixel and of less than 500 ns per double column of pixels. The layout area is 25.68×1.13 mm2. The power density in trigger mode and in triggerless mode are estimated as 25∼30 mW/cm2 and 35∼45 mW/cm2 respectively.
Abstract
The High Granularity Timing Detector (HGTD) will be installed in the ATLAS experiment to
mitigate pile-up effects during the High Luminosity (HL) phase of the Large Hadron Collider (LHC)
at ...CERN. Low Gain Avalanche Detectors (LGADs) will provide high-precision measurements of the time
of arrival of particles at the HGTD, improving the particle-vertex assignment. To cope with the
high-radiation environment, LGADs have been optimized by adding carbon in the gain layer, thus
reducing the acceptor removal rate after irradiation. Performances of several carbon-enriched
LGAD sensors from different vendors, and irradiated with high fluences of
1.5 and 2.5 × 10
15
n
eq
/cm
2
, have been measured in beam test campaigns during the
years 2021 and 2022 at CERN SPS and DESY. This paper presents the results obtained with data
recorded by an oscilloscope synchronized with a beam telescope which provides particle position
information within a resolution of a few μm. Collected charge, time resolution and hit
efficiency measurements are presented. In addition, the efficiency uniformity is also studied as a
function of the position of the incident particle inside the sensor pad.
Abstract
The proposed Circular Electron Positron Collider (CEPC)
imposes unique requirements on the vertex detector. In response, the
MOST1 and MOST2 projects were launched with the aim of developing ...a
fully functional pixel sensor and implementing the prototype of the
inner tracking detector. To efficiently manage the data flow from
multiple sensors, specialized readout electronics are required. In
order to evaluate the MOST2 project indicators set for the vertex
detector prototype, a beam telescope was constructed using six
TaichuPix-3 sensor chips and applied in different experiments. The
experimental results demonstrate that the telescope functions
effectively and that the detector prototype meets the design
objectives of the MOST2 project. This project encompasses the design
of the readout electronics, the functionality of the readout system,
the architecture of the telescope, and the specifics of the
telescope experiments.
Abstract
AC-Coupled Low Gain Avalanche Diodes (AC-LGADs) are a new type of silicon sensors which conceived for experiments at future colliders. As an evolution of the standard Low Gain Avalanche ...Diodes (LGADs), AC-LGADs have similar fast timing performance. The innovation is that AC-LGADs are available to provide fine temporal and spatial resolution simultaneously, thanks to two key features: AC-coupled readout through the dielectric layer and a continuous resistive n+ implant. The Institute of High Energy Physics (IHEP) High-Granularity Timing Detector group is developing its first version of AC-LGAD sensors. This paper present the impact of following parameters on AC-LGAD sensor performance: n+ dose, dielectric material and thickness, pad/pitch ratio and the distance between pad and cathode. All data are obtained from 2D Technology Computer-Aided Design (TCAD) simulations. The simulations will benefit future design and optimization.
Abstract
The High Granularity Timing Detector (HGTD) will be
installed in the ATLAS detector to mitigate pile-up effects during
the High Luminosity (HL) upgrade of the Large Hadron Collider (LHC)
at ...CERN. The design of the HGTD is based on the use of Low Gain
Avalanche Detectors (LGADs), with an active thickness of
50 μm, that allow to measure with high-precision the time of
arrival of particles. The HGTD will improve the particle-vertex
assignment by measuring the track time with a resolution ranging
from approximately 30 ps at the beginning of the HL-LHC operations
to 50 ps at the end. Performances of several unirradiated, as well
as neutron- and proton-irradiated, LGAD sensors from different
vendors have been measured in beam test campaigns during the years
2018 and 2019 at CERN SPS and DESY. This paper presents the results
obtained with data recorded by an oscilloscope synchronized with a
beam telescope which provides particle position information within a
resolution of a few μm. Collected charge, time resolution and
hit efficiency are presented. In addition to these properties, the
charge uniformity is also studied as a function of the position of
the incident particle inside the sensor pad.
Down-core changes in sedimentary facies, elemental geochemistry, pollen, spore, δ13C, δ15N and radiocarbon records from a filled lake, named R4, of the Serra Sul dos Carajás were used to study the ...relationship between the paleomorphological and paleoecological processes and their significance for Holocene paleoclimatology of the southeast Amazonia. The sediment deposition of the R4 lake started around 9500 cal yr BP. Increase of detrital components from 9500 to 7000 cal yr BP suggests high weathering of surrounding catchment rocks and soils, and deposition into the lake basin under mudflows. At that time, montane savanna and forest formation were already established suggesting predominance of wet climate. However, from 7000 to 3000 cal yr BP, a decline of detrital input occurred. Also, forest formation and pteridophytes were declined, while palms and macrophytes were remained relatively stable, indicating that water levels of the lake is likely dropped allowing the development of plants adapted to subaerial condition under drier climate conditions. After 3000 cal yr BP, eutrophication and low accommodation space lead to high lake productivity and the final stage of the lake filling respectively, and forest formation may has acquired its current structure, which suggests return of wetter climate conditions.
Interconnection limits seem to be a potential problem to the evolution of the semiconductor industry, especially in the nanoscale. In this work, the electrical performance of basic cells is studied ...with the help of a simple interconnection model, whose parameters can be changed. Our goal, with this study, is to determine the interconnection's influence upon the circuit behavior and to establish interconnection-related limits for its functionality. An extrapolation to more complex circuit topologies is also discussed. Finally, the implementation possibilities using new interconnection technologies, like carbon nanotubes, are presented.
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