| 1151. |
- Helenius, Ilkka, et al.
(författare)
-
NPDF constraints from the Large Hadron Electron Collider
- 2016
-
Ingår i: Proceedings of Science. - 1824-8039. ; 11-15-April-2016
-
Tidskriftsartikel (refereegranskat)abstract
- An updated analysis regarding the expected nuclear PDF constraints from the future Large Hadron Electron Collider (LHeC) experiment is presented. The new study is based on a more flexible small-x parametrization which provides less biased uncertainty estimates in the region where there are currently no data constraints. The effect of the LHeC is quantified by directly including a sample of pseudodata according to the expected precision of this planned experiment. As a result, a significant reduction of the small-x uncertainties in sea quarks and gluons is observed.
|
|
| 1152. |
- Helgeson, Ulf, 1943-
(författare)
-
Mössbauer studies of electron population in some iron complexes
- 1983
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A Mössbauer effect measuring system has been constructed. With the use of a liquid helium cryostat measurements are performed at room liquid nitrogen and liquid helium temperature. A superconducting magnet with fields up to 5 Tesla has been used in the cryostat. Mossbauer isomer shifts and quadrupole splittings as well as ESCA electron binding energies are reported for a series of iron complexes representing different types of coordination.A method to combine experimental results from Mossbauer, ESCA and IR measurements is used to estimate the electronic population of the valence shell of iron.Occupation numbers for the 3d, 4s and 4p shells are reported for dithiolate complexes, betadiketonates and cyano-, thiocyanato and halogeno-complexes of iron. These valence shell populations are compared to Extended Hückel SCC calculations.
|
|
| 1153. |
- Hellman, Sten, et al.
(författare)
-
A Strategy to Detect and Identify Gluino R-hadrons with the ATLAS Experiment at the LHC
- 2005
-
Ingår i: ATL-COM-PHYS. - Geneva : CERN. ; :065
-
Tidskriftsartikel (refereegranskat)abstract
- The potential of the ATLAS detector at the LHC to detect and quantify the production of gluino R-hadrons is investigated. Using QCD-based models and a full detector simulation, a search strategy is outlined which uses the property that gluino R-hadrons can change the sign of their charge when propagating through matter. By comparing charged tracks in the Inner and Muon tracking systems, it is shown that this observable can be used to both detect and identify gluino R-hadrons of masses up to around 1 TeV in early LHC running
|
|
| 1154. |
- Henningsson, Axel, et al.
(författare)
-
xrd_simulator: 3D X-ray diffraction simulation software supporting 3D polycrystalline microstructure morphology descriptions
- 2023
-
Ingår i: Journal of Applied Crystallography. - 1600-5767. ; 56:1, s. 282-292
-
Tidskriftsartikel (refereegranskat)abstract
- An open source Python package named xrd_simulator, capable of simulating geometrical interactions between a monochromatic X-ray beam and a polycrystalline microstructure, is described and demonstrated. The software can simulate arbitrary intragranular lattice variations of single crystals embedded within a multiphase 3D aggregate by making use of a tetrahedral mesh representation where each element holds an independent lattice. By approximating the X-ray beam as an arbitrary convex polyhedral region in space and letting the sample be moved continuously through arbitrary rigid motions, data from standard and non-standard measurement sequences can be simulated. This implementation is made possible through analytical solutions to a modified, time-dependent version of the Laue equations. The software, which primarily targets three-dimensional X-ray diffraction microscopy (high-energy X-ray diffraction microscopy) type experiments, enables the numerical exploration of which sample quantities can and cannot be reconstructed for a given acquisition scheme. Similarly, xrd_simulator targets investigations of different measurement sequences in relation to optimizing both experimental run times and sampling.
|
|
| 1155. |
- Herdrich, M. O., et al.
(författare)
-
Application of a metallic-magnetic calorimeter for high-resolution x-ray spectroscopy of Fe at an EBIT
- 2024
-
Ingår i: Journal of Physics B. - 0953-4075 .- 1361-6455. ; 57:8
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, we present an experiment conducted at the S-EBIT-I ion trap of GSI. It involved the study of ion-electron collisions of Fe and Ba ions in various charge states with the electron beam. Characteristic x-ray radiation emitted during the continuous interaction was recorded utilizing an energy-dispersive maXs-30 detector based on metallic-magnetic calorimeter (MMC) technology. Optimizations to the applied sensitivity-drift correction and energy calibration procedures significantly improved the achieved energy resolution compared to previous applications of a similar detector. This made it possible to individually resolve and identify overlapping x-ray lines of iron and barium in a wide spectral range. As a demonstration of the outstanding detector performance, we used the recorded spectral data to extract an estimate of the charge state distribution of Fe ions in the trap. This experiment campaign marks an important milestone in the ongoing effort to enable the deployment of MMC detectors for future high-precision measurements in fundamental physics experiments.
|
|
| 1156. |
- Hesami, Sara, 1983, et al.
(författare)
-
Amplitude Varying Phased Array Linearization
- 2021
-
Ingår i: 2020 50th European Microwave Conference, EuMC 2020. ; , s. 348-351
-
Konferensbidrag (refereegranskat)abstract
- A new optimization technique for amplitude-varying phased array digital predistortion (DPD) is presented. The new technique improves the linearization compared to the conventional phased array DPD techniques as the amplitude variation increases across the array. The measurement results indicate that linearization can change the adjacent channel power (ACP) pattern leading to increased ACP in the sidelobes. This sheds light on the trade-off between the main beam and side-lobes levels in the ACP pattern under different DPD techniques. We evaluate total radiated ACP or integrated ACP (IACP) and peak of ACP (PACP). We show that slight amplitude variation improves the IACP and PACP. However, as the amplitude variation increases, IACP of phased array with DPD is worsened compared to phased array without DPD.
|
|
| 1157. |
- Heyl, C. M., et al.
(författare)
-
A nozzle for high-density supersonic gas jets at elevated temperatures
- 2018
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 89:11
-
Tidskriftsartikel (refereegranskat)abstract
- We present the development of a gas nozzle providing high-density gas at elevated temperatures inside a vacuum environment. Fused silica is used as the nozzle material to allow the placement of the nozzle tip in close proximity to an intense, high-power laser beam, while minimizing the risk of sputtering nozzle tip material into the vacuum chamber. Elevating the gas temperature increases the gas-jet forward velocity, allowing us to replenish the gas volume in the laser-gas interaction region between consecutive laser shots. The nozzle accommodates a 50 μm opening hole from which a supersonic gas jet emerges. Heater wires are used to bring the nozzle temperature up to 730 °C, while a cooling unit ensures that the nozzle mount and the glued nozzle-to-mount connection is kept at a temperature below 50 °C. The presented nozzle design is used for high-order harmonic generation in hot gases using gas backing pressures of up to 124 bars.
|
|
| 1158. |
- Hidvegi, Attila, et al.
(författare)
-
An Advanced FPGA Based Phase-Lock-Loop System as an Alternative Solution for the XFEL Timing System
- 2009
-
Ingår i: Nuclear Science Symposium Conference Record (NSS/MIC), 2009 IEEE. - 9781424439614 ; , s. 1871-1872
-
Konferensbidrag (refereegranskat)abstract
- The European XFEL project requires a high-speed, very precise clock and timing distribution over large distances. A prototype system which fulfils current requirements that uses high-end components has just been completed and is being tested. However, the system is quite complicated and the boards are very complex, being designed using the small micro-TCA form factor. A way to simplify the system, and perhaps reduce cost, would be to implement an Advanced PLL in the programmable logic of an FPGA, which then would control an external VCO. By doing so several major issues could be resolved at the same time, while making more use of the advanced features of modern FPGAs. Such a system could be an alternative solution to the complex part of the Timing and Triggering System for XFEL.
|
|
| 1159. |
- Hidvegi, Attila, et al.
(författare)
-
Timing and Triggering System Prototype for the XFEL Project
- 2010
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 58:4, s. 1852-1856
-
Tidskriftsartikel (refereegranskat)abstract
- The European X-ray Free Electron Laser (XFEL) [1] at DESY in Hamburg will begin operating in the next few years, enabling new, ground-breaking research opportunities. The entire system requires very precise clock and trigger distribution, synchronous with the 1.3 GHz system RF-frequency, over distances of more than 3.4 km. The new experiment demanded features that other commercial solutions could not yet provide. Researchers at Stockholm University and DESY have developed a prototype for the timing system of XFEL. It has been decided that XFEL will use modern ATCA and Micro-TCA systems because of their advanced features and reliability. The timing system has been adapted to the Micro-TCA bus standard and also follows the new upcoming xTCA for physics standard. The prototype is fully functional and complete. It will serve as a platform for future development of the whole timing system. This paper describes the hardware design and some test results using the prototype board.
|
|
| 1160. |
- Hill, Victoria C R, et al.
(författare)
-
Particle-in-cell simulation of the third harmonic cavity F-Tube klystron
- 2016
-
Ingår i: 2016 IEEE International Vacuum Electronics Conference, IVEC 2016. - 9781467392167
-
Konferensbidrag (refereegranskat)abstract
- Use of a second harmonic and third harmonic cavity within a klystron to increase efficiency has been studied using particle-in-cell (PIC) code, MAGIC 2D. The six cavity device has a drive frequency of 1GHz, a predicted efficiency of 88%, 39 dB gain and an output power of 833 kW. The preliminary simulation results have revealed indications of bunching with bunch core oscillations. The initial results and analysis of the F-Tube PIC study are presented.
|
|
