A charge preamplifier has been developed in a 65-nm CMOS technology for processing the signals from the inner pixel layers of the CMS detector, in view of the experiment upgrade for the High-Luminosity (HL) Large Hadron Collider (LHC). The circuit is part of a readout channel implementing a time-over-threshold method for the analog-to-digital conversion of the input charge signal. Samples of the circuit have been exposed to high doses of ionizing radiation, up to 500 Mrad(SiO2), from a low-energy proton source and from an X-ray tube. The test results show that the performance degradation, in terms of charge sensitivity, signal shape, and noise, is compatible with operation in the harsh environment of the HL-LHC. Measurement data from the characterization of preamplifiers using different kinds of capacitors in the feedback network help to gain some insight into the damage mechanisms in pMOS transistors irradiated with large ionizing doses. The dependence of performance degradation on the kind of radiation source used in the tests is also discussed.

65-nm CMOS Front-End Channel for Pixel Readout in the HL-LHC Radiation Environment

The High Luminosity Large Hadron Collider (HL-LHC) project will extend the discovery reach and the capability for precision measurements in particle physics. Its program is enabled by advances in accelerator and detector technology. The LHC accelerator complex will undergo successive upgrades until 2025. To meet the experimental challenges of the increased instantaneous luminosity of up to a factor 7 with respect to the design value, 1034cm−2 s−1, the ATLAS experiment will undergo a replacement of the tracker system to sustain and improve the performance of the present detector. Due to the reduced material budget and the high charge collection and tracking efficiency, thin n-in-p planar pixel modules are promising candidates to instrument parts of the new pixel system. Pixel modules assembled with 100 μm and 150 μm thick sensors are the focus of this thesis. They are characterised exploiting different methodologies. In particular, the charge collection and hit efficiencies are studied before and after irradiation up to the expected maximum fluence range in the HL-LHC of 1016 neq cm−2. Additionally, the transient current technique is used to investigate charge collection and electric field properties within the sensor depth of 100 μm and 150 μm thick sensors. In the course of this thesis, a study is performed on the effect of different geometries of the biasing structures, necessary to perform IV measurements of the sensors before the interconnection to the readout chip. Given the fact that these structures cause a decrease of the hit efficiency after irradiation, the best technological solutions are investigated with beam test campaigns. To maintain the present level of occupancy also at the high particle multiplicity of the HL-LHC, a new readout chip was developed with a chip cell size of 50×50 μm2, resulting in a higher granularity with respect to the present chip cell size of 50×250 μm2. Sensors compatible with the current readout chip but subdivided into smaller pixel cells of 50x50 μm2 size were designed and are characterised to make first predictions for the performance of small pixel cells in the HL-LHC environment.

Development of pixel detectors for the inner tracker upgrade of the ATLAS experiment

The innermost part of the tracking detector of the ATLAS experiment consists mainly of planar n + -in-n silicon pixel sensors During the phase-0 upgrade, the Insertable B-Layer (IBL) was installed closest to the beam pipe Its pixels are arranged with a pitch of 250  μ m × 50 μ m with a rectangular shaped n + implantation Based on this design modified pixel designs have been developed in Dortmund Six of these new pixel designs are arranged in structures of ten columns and were placed beside structures with the standard design on one sensor Because of a special guard ring design, each structure can be powered and investigated separately Several of these sensors were bump bonded to FE-I4 read-out chips One of these modules was irradiated with reactor neutrons up to a fluence of 5 × 1 0 15 n eq cm − 2  This contribution presents important sensor characteristics, charge collection determined with radioactive sources and hit efficiency measurements, performed in laboratory and test beam, of this irradiated device It is shown that the new modified designs perform similar or better than the IBL standard design in terms of charge collection and tracking efficiency, at the cost of a slightly increased leakage current

/pdf/investigation-of-modified-atlas-pixel-implantations-after-2nf8lcppaj.pdf

Investigation of modified ATLAS pixel implantations after irradiation with neutrons

A front-end channel prototype for pixel detectors has been designed for the upgrades of the HL-LHC experiments. The circuit is based on a Krummenacher feedback network to continuously reset the charge sensitive amplifier and on a fast threshold discriminator to implement a time-over-threshold (ToT) method and perform amplitude measurement. The front-end circuit was developed in a 65 nm CMOS technology and takes an overall area not exceeding 1250 $\mu \text {m}^{2}$ , i.e., half of the overall pixel area. The current consumption per channel is around 4 $\mu \text {A}$ at $VDD=1.2$ V. A very small charge sensitivity dispersion was detected in the set of characterized samples. An equivalent noise charge of 120 e− was found for a detector capacitance of 100 fF. The response of the channel is compatible with the speed requirements of the foreseen application in the innermost layers of the CMS pixel detector.

A Front-End Channel in 65 nm CMOS for Pixel Detectors at the HL-LHC Experiment Upgrades

Research and development laboratory measurements of non-irradiated and irradiated planar n + -in-n pixel sensor structures are systematically investigated to determine the power dissipation of those sensors. Measurements were taken at different operation temperatures, sensor bias voltages, bulk thicknesses, sensor areas, and irradiation fluences. For planar n + -in-n pixel sensors irradiated to HL-LHC fluences of some 10 16 n eq cm − 2 a power dissipation area density of (126±8) mW cm –2 at a temperature of −25 °C and at an operation voltage of 800 V is derived for small sensors with an area of about 0.7 cm 2 . For large sensors as planned for the ATLAS phase-II upgrade a power dissipation of 100 mW cm –2 is expected.

Power dissipation studies on planar n+-in-n pixel sensors

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

D. Bryan

Author Tools

Chat about Author

Papers

Power dissipation studies on planar n+-in-n pixel sensors