Monolithic Pixel Sensors in Deep-Submicron SOI Technology

Monolithic pixel sensors for charged particle detection and imaging applications have been designed and fabricated using commercially available, deep-submicron Silicon-On-Insulator (SOI) processes, which insulate a thin layer of integrated full CMOS electronics from a high-resistivity substrate by means of a buried oxide. The substrate is contacted from the electronics layer through vias etched in the buried oxide, allowing pixel implanting and reverse biasing. This paper summarizes the performances achieved with a first prototype manufactured in the OKI 0.15 micrometer FD-SOI process, featuring analog and digital pixels on a 10 micrometer pitch. The design and preliminary results on the analog section of a second prototype manufactured in the OKI 0.20 micrometer FD-SOI process are briefly discussed.Comment: Proceedings of the PIXEL 2008 International Workshop, FNAL, Batavia, IL, 23-26 September 2008. Submitted to JINST - Journal of Instrumentatio

Neurons Responsive to Global Visual Motion Have Unique Tuning Properties in Hummingbirds

Neurons in animal visual systems that respond to global optic flow exhibit selectivity for motion direction and/or velocity. The avian lentiformis mesencephali (LM), known in mammals as the nucleus of the optic tract (NOT), is a key nucleus for global motion processing [1–4]. In all animals tested, it has been found that the majority of LM and NOT neurons are tuned to temporo-nasal (back-to-front) motion [4–11]. Moreover, the monocular gain of the optokinetic response is higher in this direction, compared to naso-temporal (front-to-back) motion [12, 13]. Hummingbirds are sensitive to small visual perturbations while hovering, and they drift to compensate for optic flow in all directions [14]. Interestingly, the LM, but not other visual nuclei, is hypertrophied in hummingbirds relative to other birds [15], which suggests enhanced perception of global visual motion. Using extracellular recording techniques, we found that there is a uniform distribution of preferred directions in the LM in Anna’s hummingbirds, whereas zebra finch and pigeon LM populations, as in other tetrapods, show a strong bias toward temporo-nasal motion. Furthermore, LM and NOT neurons are generally classified as tuned to ‘‘fast’’ or ‘‘slow’’ motion [10, 16, 17], and we predicted that most neurons would be tuned to slow visual motion as an adaptation for slow hovering. However, we found the opposite result: most hummingbird LM neurons are tuned to fast pattern velocities, compared to zebra finches and pigeons. Collectively, these results suggest a role in rapid responses during hovering, as well as in velocity control and collision avoidance during forward flight of hummingbirds

Pretectal projections to the oculomotor cerebellum in hummingbirds ( Calypte anna ), zebra finches ( Taeniopygia guttata ), and pigeons ( Columba livia )

In birds, optic flow is processed by a retinal‐recipient nucleus in the pretectum, the nucleus lentiformis mesencephali (LM), which then projects to the cerebellum, a key site for sensorimotor integration. Previous studies have shown that the LM is hypertrophied in hummingbirds, and that LM cell response properties differ between hummingbirds and other birds. Given these differences in anatomy and physiology, we ask here if there are also species differences in the connectivity of the LM. The LM is separated into lateral and medial subdivisions, which project to the oculomotor cerebellum and the vestibulocerebellum. In pigeons, the projection to the vestibulocerebellum largely arises from the lateral LM; the projection to the oculomotor cerebellum largely arises from the medial LM. Here, using retrograde tracing, we demonstrate differences in the distribution of projections in these pathways between Anna's hummingbirds (Calypte anna ), zebra finches (Taeniopygia guttata ), and pigeons (Columba livia ). In all three species, the projections to the vestibulocerebellum were largely from lateral LM. In contrast, projections to the oculomotor cerebellum in hummingbirds and zebra finches do not originate in the medial LM (as in pigeons) but instead largely arise from pretectal structures just medial, the nucleus laminaris precommissuralis and nucleus principalis precommissuralis. These species differences in projection patterns provide further evidence that optic flow circuits differ among bird species with distinct modes of fligh

Theoretical study of dark resonances in micro-metric thin cells

We investigate theoretically dark resonance spectroscopy for a dilute atomic vapor confined in a thin (micro-metric) cell. We identify the physical parameters characterizing the spectra and study their influence. We focus on a Hanle-type situation, with an optical irradiation under normal incidence and resonant with the atomic transition. The dark resonance spectrum is predicted to combine broad wings with a sharp maximum at line-center, that can be singled out when detecting a derivative of the dark resonance spectrum. This narrow signal derivative, shown to broaden only sub-linearly with the cell length, is a signature of the contribution of atoms slow enough to fly between the cell windows in a time as long as the characteristic ground state optical pumping time. We suggest that this dark resonance spectroscopy in micro-metric thin cells could be a suitable tool for probing the effective velocity distribution in the thin cell arising from the atomic desorption processes, and notably to identify the limiting factors affecting desorption under a grazing incidence.Comment: 12 pages, 11 figures theoretical articl

Les temps de la consultation du comité d’entreprise

The DD4HEP detector description toolkit offers a flexible and easy-to-use solution for the consistent and complete description of particle physics detectors in a single system. The sub-component DDREC provides a dedicated interface to the detector geometry as needed for event reconstruction. With DDREC there is no need to define an additional, separate reconstruction geometry as is often done in HEP, but one can transparently extend the existing detailed simulation model to be also used for the reconstruction. Based on the extension mechanism of DD4HEP, DDREC allows one to attach user defined data structures to detector elements at all levels of the geometry hierarchy. These data structures define a high level view onto the detectors describing their physical properties, such as measurement layers, point resolutions, and cell sizes. For the purpose of charged particle track reconstruction, dedicated surface objects can be attached to every volume in the detector geometry. These surfaces provide the measurement directions, local-to-global coordinate transformations, and material properties. The material properties, essential for the correct treatment of multiple scattering and energy loss effects in charged particle reconstruction, are automatically averaged from the detailed geometry model along the normal of the surface. Additionally, a generic interface allows the user to query material properties at any given point or between any two points in the detector's world volume. In this paper we will present DDREC and how it is used together with the linear collider tracking software and the particle-flow package PANDORAPFA for full event reconstruction of the ILC detector concepts ILD and SiD, and of CLICdp. This flexible tool chain is also well suited for other future accelerator projects such as FCC and CEPC

Calomplification — the power of generative calorimeter models

Motivated by the high computational costs of classical simulations, machine-learned generative models can be extremely useful in particle physics and elsewhere. They become especially attractive when surrogate models can efficiently learn the underlying distribution, such that a generated sample outperforms a training sample of limited size. This kind of GANplification has been observed for simple Gaussian models. We show the same effect for a physics simulation, specifically photon showers in an electromagnetic calorimeter

Testing the Higgs Mechanism in the Lepton Sector with multi-TeV e+e- Collisions

Multi-TeV e+e- collisions provide with a large enough sample of Higgs bosons to enable measurements of its suppressed decays. Results of a detailed study of the determination of the muon Yukawa coupling at 3 TeV, based on full detector simulation and event reconstruction, are presented. The muon Yukawa coupling can be determined with a relative accuracy of 0.04 to 0.08 for Higgs bosons masses from 120 GeV to 150 GeV, with an integrated luminosity of 5 inverse-ab. The result is not affected by overlapping two-photon background.Comment: 6 pages, 2 figures, submitted to J Phys G.: Nucl. Phy

Cost-Effectiveness of Intensified Versus Conventional Multifactorial Intervention in Type 2 Diabetes: Results and projections from the Steno-2 study

OBJECTIVE—To assess the cost-effectiveness of intensive versus conventional therapy for 8 years as applied in the Steno-2 study in patients with type 2 diabetes and microalbuminuria