In-situ growth optimization in focused electron-beam induced deposition

We present the application of an evolutionary genetic algorithm for the in-situ optimization of nanostructures prepared by focused electron-beam-induced deposition. It allows us to tune the properties of the deposits towards highest conductivity by using the time gradient of the measured in-situ rate of change of conductance as fitness parameter for the algorithm. The effectiveness of the procedure is presented for the precursor W(CO)6 as well as for post-treatment of Pt-C deposits obtained by dissociation of MeCpPt(Me)3. For W(CO)6-based structures an increase of conductivity by one order of magnitude can be achieved, whereas the effect for MeCpPt(Me)3 is largely suppressed. The presented technique can be applied to all beam-induced deposition processes and has great potential for further optimization or tuning of parameters for nanostrucures prepared by FEBID or related techniques

A Draft of the Human Septin Interactome

Background: Septins belong to the GTPase superclass of proteins and have been functionally implicated in cytokinesis and the maintenance of cellular morphology. They are found in all eukaryotes, except in plants. In mammals, 14 septins have been described that can be divided into four groups. It has been shown that mammalian septins can engage in homo- and heterooligomeric assemblies, in the form of filaments, which have as a basic unit a hetero-trimeric core. In addition, it has been speculated that the septin filaments may serve as scaffolds for the recruitment of additional proteins. Methodology/Principal Findings: Here, we performed yeast two-hybrid screens with human septins 1-10, which include representatives of all four septin groups. Among the interactors detected, we found predominantly other septins, confirming the tendency of septins to engage in the formation of homo- and heteropolymeric filaments. Conclusions/Significance: If we take as reference the reported arrangement of the septins 2, 6 and 7 within the heterofilament, (7-6-2-2-6-7), we note that the majority of the observed interactions respect the ""group rule"", i.e. members of the same group (e. g. 6, 8, 10 and 11) can replace each other in the specific position along the heterofilament. Septins of the SEPT6 group preferentially interacted with septins of the SEPT2 group (p<0.001), SEPT3 group (p<0.001) and SEPT7 group (p<0.001). SEPT2 type septins preferentially interacted with septins of the SEPT6 group (p<0.001) aside from being the only septin group which interacted with members of its own group. Finally, septins of the SEPT3 group interacted preferentially with septins of the SEPT7 group (p<0.001). Furthermore, we found non-septin interactors which can be functionally attributed to a variety of different cellular activities, including: ubiquitin/sumoylation cycles, microtubular transport and motor activities, cell division and the cell cycle, cell motility, protein phosphorylation/signaling, endocytosis, and apoptosis.Fundao de Amparo a Pesquisa do Estado Sao Paulo (Fapesp)CAPES: Coordenao de Aperfeioamento de Pessoal de Navel SuperiorConselho Nacional de Pesquisa e Desenvolvimento (CNPq)Laboratorio Nacional de Biociencias-Centro Nacional de Pesquisa em Energia e Materais (LNBio-CNPEM

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Level-1 Calorimeter Trigger: From Virtex-7 to UltraScale+

With the restart of the LHC in 2021 the ATLAS experiment has to cope with high-luminosity beams. Therefore, a new Level-1 Calorimeter Trigger system will be introduced exploiting a finer calorimeter readout granularity. The new system consists of three Feature EXtractors (FEXs) - electron FEX (eFEX), jet FEX (jFEX) and global FEX (gFEX) - that use FPGAs to reconstruct different physics objects used for the trigger selection and that gather data from the calorimeters through optical fibres. The Trigger Objects (TOBs) produced by the algorithms running on the FEXs are optically sent to the Level-1 Topological Processor (L1Topo), where interesting physics events are selected by e.g. applying kinematic and angular requirements. This contribution will focus on the new jFEX system and on the upgrade of the L1Topo giving an overview of the hardware as well as the algorithmic firmware

Challenges and performance of the frontier technology applied to an ATLAS Phase-I calorimeter trigger board dedicated to the jet identification

The 'Phase-I' upgrade of the Large Hadron Collider (LHC), scheduled to be completed in 2021, will lead to an enhanced collision luminosity of 2.5x10e34cm-2s-1. To cope with the new and challenging accelerator conditions, all the CERN experiments have planned a major detector upgrade to be installed during the associated experimental shutdown period. One of the physics goals of the ATLAS experiment is to maintain sensitivity to electroweak processes despite the increased number of interactions per LHC bunch crossing. To this end, the component of the first level hardware trigger based on calorimeter data will be upgraded to exploit fine-granularity readout using a new system of Feature EXtractors (FEXs), which each uses different physics objects for trigger selection. There will be three FEX systems in total, with this contribution focusing on the first prototype of the jet FEX (jFEX). This system identifies jets and large area tau candidates while also calculating global variables such as transverse energy sums and missing transverse energy. The jFEX prototype is characterised by four large Xilinx Ultrascale Field Programmable Gate Arrays (FPGAs), XCVU190FLGA2577, so far the largest available on the market, capable of handling a data volume of more than 3 TB/s of input bandwidth. The choice of such large devices was driven by the requirement for large input bandwidth and processing power. This comes from the need to exploit high granularity calorimeter information and also run several jet identification algorithms within the few hundred nanoseconds latency budget (~350 ns). This presentation will report on the hardware design challenges and adopted solutions to preserve signal integrity within a densely populated high signal speed ATCA board. The parallel simulation activity that supported and validated the board design will also be presented. Particular emphasis will be given to the large FPGA power consumption effects on the boards. This was assessed via dedicated thermal simulation and cross-checked with a campaign of measurements. Preliminary results will also be presented from tests both at CERN and Mainz, based on the first jFEX prototype from December 2016

Latest Frontier Technology and Design of the ATLAS Calorimeter Trigger Board Dedicated to Jet Identification for the LHC Run 3

To cope with the enhanced luminosity of the beam delivered by the Large Hadron Collider (LHC) in 2020, the A Thoroidal LHC ApparatuS (ATLAS) experiment has planned a major upgrade. As part of this, the trigger at Level-I based on calorimeter data, will be upgraded to exploit fine-granularity readout using a new system of Feature Extractors, which differ in the physics objects for the trigger selection. The presentation is focused on the jet Feature EXtractor (jFEX) prototype, one of the three Feature Extractors. In few hundreds nanoseconds latency budget, up to 2 TB/s have to be processed to provide jet identification (even large area jets) and measurements of global variables. This requires the use of large Field Programmable Gate Array (FPGA) with the largest Multi Giga Transceiver available on the market. The jFEX board prototype hosts four large FPGAs from the Xilinx Ultrascale family with 120 Multi Giga Transceivers each, connected to 24 opto-electrical devices, resulting in a densely populated high speed signals board. For the 24 layers jFEX board stack-up, the MEGTRON6 material was chosen for its property of low transmission loss with high frequency signals (GHz range) and to further preserve the signal integrity, special care has been put into the design accompanied by simulation to optimise the voltage drop and minimise the current density over the power planes. An integrated test has been installed at the ATLAS test facility to perform numerous tests and measurements with the JFEX prototype

Development of the jet Feature EXtractor (jFEX) for the ATLAS Level 1 calorimeter trigger upgrade at the LHC

To cope with the enhanced luminosity delivered by the Large Hadron Collider from 2021 onwards, the ATLAS experiment has planned several upgrades. The first level trigger based on calorimeter data will be upgraded to exploit fine-granularity readout using a new system of Feature EXtractors (FEXs, FPGA-based trigger boards), each optimized to trigger on different physics objects. This contribution is focused on the jet FEX. The main challenges of such a board are the input bandwidth of up to 3.1 Tbps, dense routing of high-speed signals and power consumption. The design, PCB simulations and results of integrated tests of a prototype are shown in this document