Development of an Optimized Quadrupole Resonator at HZB

Abstract Current superconducting cavities are generally made of solid Niobium. A possibility to reduce cost as well as increase the quality factor and or accelerating fields is to use thin film coated cavities. Apart from Niobium thin films, other substances such as Magnesium diboride, Niobium nitride and Niobium tin are promising candidates. Measuring the RF properties of superconducting thin films, specifically the surface resistance, with a high resolution at frequencies, magnetic field levels and operating temperature as realized in RF cavities, is needed to drive forward this development. Presently, only few setups exist capable of measuring the surface resistance of thin films samples with a resolution in the nano ohm range at RF frequencies below 3 GHz. A dedicated test stand consisting of a quadrupole resonator is therefore being constructed at the Helmholtz Zentrum Berlin. Starting with the 400 MHz quadrupole resonator developed by CERN, the design was adapted and optimized to 433 MHz making available the higher harmonic mode at 1.3 GHz for RF characterization of samples in the L band using simulation data obtained with CST Microwave Studio. A number of relevant figures of merit have been improved to provide a higher resolution, a lower peak electric field and less sensitivity to microphonics, enabling measurements with high resolution at high magnetic field level

Creation of model of the photon beam with a treatment planning system PLUNC for ELEKTA Synergy linear accelerator

In the present study, we performed a comparison and selection of the most appropriate treatment plan with an educational treatment planning system PLUNC which was provide recommended absorbed dose of ionizing radiation in tumor volume, and the minimum value of the dose in organs at risk and normal tissues surrounding the tumor. For this reason, was created model of the photon beam for ELEKTA Synergy Linear Accelerator. The treatment plan was developed for patients with rectal cancer. The simulation was performed on the basis of actual dicom - images of the tumor, which was obtained with modern medical equipment (computed tomography Aquilion Toshiba). For checking of the simulated plan quality, reference dose and dose rate measurements were performed. Present study demonstrates the relationship between the dose distributions and selected treatment plan. As result of research, was conducted comparison and analysis of algorithms for dose calculation in tissueequivalent environment with a treatment planning system PLUNC. Was developed methodological guide for work in the PLUNC software. Thereby, educational treatment planning system PLUNC was put into operation

POSITION AND ALIGNMENT OF FLEX ZONES IN RUNNING SHOES

The right position and alignment of forefoot flexibility zones in running shoes represents a precondition to avoid overuse injuries of the foot and leg. The goal of this study was to determine foot anthropometries, in order to set up construction guidelines for the positioning and alignment of the flex zones in running shoes. The foot anthropometries of 471 runners were measured with a 2D scanning system under static conditions. The metatarsal-length-indices (MU) were calculated for each ray. The calculated MUs do not indicate the necessity for a grading pattern regarding different shoe sizes, gender dimorphism and different regions. To consider the anthropometrical variance of the MUs it is suggested to apply flex zones instead of only flex grooves. The results suggest the application of a transversal, a longitudinal and a diagonal flex zone in running shoes

Structural properties and anisotropic electronic transport in SrIrO3 films

Perovskite SrIrO3 (SIO) films epitaxially deposited with a thickness of about 60 nm on various substrate materials display nearly strain-relieved state. Films grown on orthorhombic (110) DyScO3 (DSO) are found to display untwinned bulk-like orthorhombic structure. However, film deposition on cubic (001) SrTiO3 induces a twinned growth of SIO. Resistance measurements on the SIO films reveal only weak temperature dependence, where the resistance R increases with decreasing temperature T. Hall measurements show dominant electron-like transport throughout the temperature range from 2 K to 300 K. At 2 K, the electron concentration and resistivity for SIO on STO amount to ne = 1.4*10^20 cm-3 and 1 mohmcm. Interestingly, the film resistance of untwinned SIO on DSO along the [1-10] and the [001] direction differs by up to 25% indicating pronounced anisotropic electronic transport. The anisotropy of the resistance increases with decreasing T and displays a distinct maximum around 86 K. The specific T-dependence is similar to that of the structural anisotropy sqrt(a2+b2)/c of bulk SIO. Therefore, anisotropic electronic transport in SIO is very likely induced by the orthorhombic distortion. Consequently, for twinned SIO films on STO anisotropy vanishes nearly completely. The experimental results show that structural changes are very likely responsible for the observed anisotropic electronic transport. The strong sensitivity of the electronic transport in SIO films may be explained in terms of the narrow electron-like bands in SIO caused by spin-orbit-coupling and orthorhombic distortion

Commissioning results of the HZB Quadrupole Resonator

Recent cavity results with niobium have demonstrated the necessity of a good understanding of both the BCS and residual resistance. For a complete picture and comparison with theory, it is essential that one can measure the RF properties as a function of field, temperature, frequency and ambient magnetic field. Standard cavity measurements are limited in their ability to change all parameters freely and in a controlled manner. On the other hand, most sample measurement setups operate at fairly high frequency, where the surface resistance is always BCS dominated. The quadrupole resonator, originally developed at CERN, is ideally suited for characterization of samples at typical cavity RF frequencies. We report on a modified version of the QPR with improved RF figures of merit for high field operation. Experimental challenges in the commissioning run and alternate designs for simpler sample changes are shown alongside measurement results of a large grain niobium sampl

Characterization of polar organosulfates in secondary organic aerosol from the unsaturated aldehydes 2-E-pentenal, 2-E-hexenal, and 3-Z-hexenal

We show in the present study that the unsaturated aldehydes 2-E-pentenal, 2-E-hexenal, and 3-Z-hexenal are biogenic volatile organic compound (BVOC) precursors for polar organosulfates with molecular weights (MWs) 230 and 214, which are also present in ambient fine aerosol from a forested site, i.e., K-puszta, Hungary. These results complement those obtained in a previous study showing that the green leaf aldehyde 3-Z-hexenal serves as a precursor for MW 226 organosulfates. Thus, in addition to isoprene, the green leaf volatiles (GLVs) 2-E-hexenal and 3-Z-hexenal, emitted due to plant stress (mechanical wounding or insect attack), and 2-E-pentenal, a photolysis product of 3-Z-hexenal, should be taken into account for secondary organic aerosol and organosulfate formation. Polar organosulfates are of climatic relevance because of their hydrophilic properties and cloud effects. Extensive use was made of organic mass spectrometry (MS) and detailed interpretation of MS data (i.e., ion trap MS and accurate mass measurements) to elucidate the chemical structures of the MW 230, 214 and 170 organosulfates formed from 2-E-pentenal and indirectly from 2-E-hexenal and 3-Z-hexenal. In addition, quantum chemical calculations were performed to explain the different mass spectral behavior of 2,3-dihydroxypentanoic acid sulfate derivatives, where only the isomer with the sulfate group at C-3 results in the loss of SO3. The MW 214 organosulfates formed from 2-E-pentenal are explained by epoxidation of the double bond in the gas phase and sulfation of the epoxy group with sulfuric acid in the particle phase through the same pathway as that proposed for 3-sulfooxy-2-hydroxy-2-methylpropanoic acid from the isoprene-related alpha,beta-unsaturated aldehyde methacrolein in previous work (Lin et al., 2013). The MW 230 organosulfates formed from 2-E-pentenal are tentatively explained by a novel pathway, which bears features of the latter pathway but introduces an additional hydroxyl group at the C-4 position. Evidence is also presented that the MW 214 positional isomer, 2-sulfooxy-3-hydroxypentanoic acid, is unstable and decarboxylates, giving rise to 1-sulfooxy-2-hydroxybutane, a MW 170 organosulfate. Furthermore, evidence is obtained that lactic acid sulfate is generated from 2-E-pentenal. This chemistry could be important on a regional and local scale where GLV emissions such as from grasses and cereal crops are substantial

Strange semimetal dynamics in SrIrO3

The interplay of electronic correlations, multi-orbital excitations, and spin-orbit coupling is afertile ground for new states of matter in quantum materials. Here, we report on a polarizedRaman scattering study of semimetallic SrIrO3. The momentum-space selectivity of Ramanscattering allows to circumvent the challenge to resolve the dynamics of charges with verydifferent mobilities. The Raman responses of both holes and electrons display an electroniccontinuum extending far beyond the energies allowed in a regular Fermi liquid. Analyzing thisresponse within a memory function formalism, we extract their frequency dependent scat-tering rate and mass enhancement, from which we determine their DC-mobilities andelectrical resistivities that agree well with transport measurement. We demonstrate that itscharge dynamics is well described by a marginal Fermi liquid phenomenology, with a scat-tering rate close to the Planckian limit. This demonstrates the potential of this approach toinvestigate the charge dynamics in multi-band systems

RIM-Binding Protein 2 organizes Ca2+channel topography and regulates release probability and vesicle replenishment at a fast central synapse

RIM-Binding Protein 2 (RIM-BP2) is a multi-domain protein of the presynaptic active zone (AZ). By binding to Rab-interacting protein (RIM), bassoon and voltage-gated Ca²⁺channels (CaV), it is considered to be a central organizer of the topography of CaVand release sites of synaptic vesicles (SVs) at the AZ. Here, we investigated the role of RIM-BP2 at the endbulb of Held synapse of auditory nerve fibers with bushy cells of the cochlear nucleus, a fast relay of the auditory pathway with high release probability. Disruption of RIM-BP2 lowered release probability altering short-term plasticity and reduced evoked excitatory postsynaptic currents (EPSCs). Analysis of SV pool dynamics during high frequency train stimulation indicated a reduction of SVs with high release probability but an overall normal size of the readily releasable SV pool (RRP). The Ca2+-dependent fast component of SV replenishment after RRP depletion was slowed. Ultrastructural analysis by super-resolution light and electron microscopy revealed an impaired topography of presynaptic CaVand a reduction of docked and membrane-proximal SVs at the AZ. We conclude that RIM-BP2 organizes the topography of CaV, and promotes SV tethering and docking. This way RIM-BP2 is critical for establishing a high initial release probability as required to reliably signal sound onset information that we found to be degraded in bushy cells of RIM-BP2-deficient mice in vivo