Radiation hardness of small-pitch 3D pixel sensors up to HL-LHC fluences

A new generation of 3D silicon pixel detectors with a small pixel size of 50$\times$50 and 25$\times$100 $\mu$m$^{2}$ is being developed for the HL-LHC tracker upgrades. The radiation hardness of such detectors was studied in beam tests after irradiation to HL-LHC fluences up to $1.4\times10^{16}$ n$_{\mathrm{eq}}$/cm$^2$. At this fluence, an operation voltage of only 100 V is needed to achieve 97% hit efficiency, with a power dissipation of 13 mW/cm$^2$ at -25$^{\circ}$C, considerably lower than for previous 3D sensor generations and planar sensors.Comment: 5 pages, 2 figures, Proceedings of TIPP 2017, Beijing (International Conference on The Technology and Instrumentation in Particle Physics 2017

Test beam Characterizations of 3D Silicon Pixel detectors

3D silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrating into the bulk material in contrast to standard Si detectors with planar electrodes on its top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as for example the radiation environment expected in an LHC upgrade. For the first time, several 3D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here we report results on unirradiated devices with three 3D electrodes per 50 x 400 um2 pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9% +- 0.1 % for tracks parallel to the electrodes and of 99.9% +- 0.1 % at 15 degrees are measured. The homogeneity of the efficiency over the pixel area and charge sharing are characterized.Comment: 5 pages, 7 figure

Electrical Properties of Carbon Fiber Support Systems

Carbon fiber support structures have become common elements of detector designs for high energy physics experiments. Carbon fiber has many mechanical advantages but it is also characterized by high conductivity, particularly at high frequency, with associated design issues. This paper discusses the elements required for sound electrical performance of silicon detectors employing carbon fiber support elements. Tests on carbon fiber structures are presented indicating that carbon fiber must be regarded as a conductor for the frequency region of 10 to 100 MHz. The general principles of grounding configurations involving carbon fiber structures will be discussed. To illustrate the design requirements, measurements performed with a silicon detector on a carbon fiber support structure at small radius are presented. A grounding scheme employing copper-kapton mesh circuits is described and shown to provide adequate and robust detector performance.Comment: 20 pages, 11 figures, submitted to NI

LArPix: Demonstration of low-power 3D pixelated charge readout for liquid argon time projection chambers

We report the demonstration of a low-power pixelated readout system designed for three-dimensional ionization charge detection and digital readout of liquid argon time projection chambers (LArTPCs). Unambiguous 3D charge readout was achieved using a custom-designed system-on-a-chip ASIC (LArPix) to uniquely instrument each pad in a pixelated array of charge-collection pads. The LArPix ASIC, manufactured in 180 nm bulk CMOS, provides 32 channels of charge-sensitive amplification with self-triggered digitization and multiplexed readout at temperatures from 80 K to 300 K. Using an 832-channel LArPix-based readout system with 3 mm spacing between pads, we demonstrated low-noise ($<$500 e$^-$ RMS equivalent noise charge) and very low-power ($<$100 $\mu$W/channel) ionization signal detection and readout. The readout was used to successfully measure the three-dimensional ionization distributions of cosmic rays passing through a LArTPC, free from the ambiguities of existing projective techniques. The system design relies on standard printed circuit board manufacturing techniques, enabling scalable and low-cost production of large-area readout systems using common commercial facilities. This demonstration overcomes a critical technical obstacle for operation of LArTPCs in high-occupancy environments, such as the near detector site of the Deep Underground Neutrino Experiment (DUNE).Comment: 19 pages, 10 figures, 1 ancillary animation. V3 includes minor revisions based on referee comment

Recent progress of the ATLAS Planar Pixel Sensor R&D Project

The foreseen luminosity upgrade for the LHC (a factor of 5-10 more in peak luminosity by 2021) poses serious constraints on the technology for the ATLAS tracker in this High Luminosity era (HL-LHC). In fact, such luminosity increase leads to increased occupancy and radiation damage of the tracking detectors. To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Planar Pixel Sensor R&D Project was established comprising 17 institutes and more than 80 scientists. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edge designs to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. In the following I will present results from the group, concerning mainly irradiated-devices performance, together with studies for new sensors, including detailed simulations.Comment: 9 pages,12 figure

Integrated Circuit Design in US High-Energy Physics

This whitepaper summarizes the status, plans, and challenges in the area of integrated circuit design in the United States for future High Energy Physics (HEP) experiments. It has been submitted to CPAD (Coordinating Panel for Advanced Detectors) and the HEP Community Summer Study 2013(Snowmass on the Mississippi) held in Minnesota July 29 to August 6, 2013. A workshop titled: US Workshop on IC Design for High Energy Physics, HEPIC2013 was held May 30 to June 1, 2013 at Lawrence Berkeley National Laboratory (LBNL). A draft of the whitepaper was distributed to the attendees before the workshop, the content was discussed at the meeting, and this document is the resulting final product. The scope of the whitepaper includes the following topics: Needs for IC technologies to enable future experiments in the three HEP frontiers Energy, Cosmic and Intensity Frontiers; Challenges in the different technology and circuit design areas and the related R&D needs; Motivation for using different fabrication technologies; Outlook of future technologies including 2.5D and 3D; Survey of ICs used in current experiments and ICs targeted for approved or proposed experiments; IC design at US institutes and recommendations for collaboration in the future

3D electronics for hybrid pixel detectors – TWEPP-09

Future hybrid pixel detectors are asking for smaller pixels in order to improve spatial resolution and to deal with an increasing counting rate. Facing these requirements is foreseen to be done by microelectronics technology shrinking. However, this straightforward approach presents some disadvantages in term of performances and cost. New 3D technologies offer an alternative way with the advantage of technology mixing. For the upgrade of ATLAS pixel detector, a 3D conception of the read-out chip appeared as an interesting solution. Splitting the pixel functionalities into two separate levels will reduce pixel size and open the opportunity to take benefit of technology's mixing. Based on a previous prototype of the read-out chip FE-I4 (IBM 130nm), this paper presents the design of a hybrid pixel read-out chip using threedimensional Tezzaron-Chartered technology. In order to disentangle effects due to Chartered 130nm technology from effects involved by 3D architecture, a first translation of FEI4 prototype had been designed at the beginning of this year in Chartered 2D technology, and first test results will be presented in the last part of this paper

Compact, directional neutron detectors capable of high-resolution nuclear recoil imaging

We report on the design, production, and performance of compact 40-cm3 Time Projection Chambers (TPCs) that detect fast neutrons by measuring the three-dimensional (3D) ionization distribution of nuclear recoils in 4He:CO2 gas at atmospheric pressure. We use these detectors to characterize the fast-neutron flux inside the Belle II detector at the SuperKEKB electron–positron collider in Tsukuba, Japan, where the primary design constraint is a small form factor. We find that the TPCs meet or exceed all design specifications, and are capable of measuring the 3D surface shape and charge density profile of ionization clouds from nuclear recoils and charged tracks in exquisite detail. Scaled-up detectors based on the detection principle demonstrated here may be suitable for directional dark matter searches, measurements of coherent neutrino–nucleus scattering, and other experiments requiring precise detection of neutrons or nuclear recoils