S. Friedrich
A5077194546- Superconducting and THz Device Technology
- Physics of Superconductivity and Magnetism
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Advanced Semiconductor Detectors and Materials
- Nuclear physics research studies
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- Superconductivity in MgB2 and Alloys
- High-pressure geophysics and materials
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Dark Matter and Cosmic Phenomena
- Calibration and Measurement Techniques
- Quantum, superfluid, helium dynamics
- Ion-surface interactions and analysis
- Medical Imaging Techniques and Applications
Lawrence Livermore National Laboratory
2016-2025
RWTH Aachen University
2023
Justus-Liebig-Universität Gießen
2011-2020
University of Bonn
2020
Los Alamos National Laboratory
2012-2020
Lawrence Livermore National Security
2018
Washington State University
2017
Austrian Academy of Sciences
2014
Kyoto University
2014
GSI Helmholtz Centre for Heavy Ion Research
2014
Despite their high relative abundance in our Universe, neutrinos are the least understood fundamental particles of nature. They also provide a unique system to study quantum coherence and wavelike nature systems due extremely weak interaction probabilities. In fact, properties emitted experimentally relevant sources virtually unknown spatial extent neutrino wavepacket is only loosely constrained by reactor oscillation data with spread 13 orders magnitude. Here, we present first direct limits...
DT neutron yield (Y(n)), ion temperature (T(i)), and down-scatter ratio (dsr) determined from measured spectra are essential metrics for diagnosing the performance of inertial confinement fusion (ICF) implosions at National Ignition Facility (NIF). A suite neutron-time-of-flight (nTOF) spectrometers a magnetic recoil spectrometer (MRS) have been implemented in different locations around NIF target chamber, providing good implosion coverage complementarity required reliable measurements Y(n),...
ZnO is a wide band gap, naturally n-type semiconductor with great promise for optoelectronic applications; the main obstacle yet to be overcome p-type doping. Nitrogen, most promising candidate currently being pursued as dopant, has been predicted preferentially incorporate into lattice in form of N-2 molecule at an O site when plasma source used, leading compensation rather than We demonstrate this incorrect by using N K-edge x-ray absorption spectra and comparing them first-principles...
The standard system architecture of PV installations exposes solar modules to bias voltages several hundred volts. Recently it became apparent that high can have negative effects on the long-term performance screen-printed crystalline silicon cells. This paper focuses study this potential induced degradation effect (PID) under laboratory conditions. A corona-discharge assembly was used polarize mini as well a setup expose 60-cell wet Different encapsulation setups and cell process variations...
The first inertial confinement fusion implosion experiments with equimolar deuterium-tritium thermonuclear fuel have been performed on the National Ignition Facility. These use 0.17 mg of potential for ignition and significant yield conditions. has fielded as a cryogenic layer inside spherical plastic capsule that is mounted in center cylindrical gold hohlraum. Heating hohlraum 192 laser beams total energy 1.6 MJ produces soft x-ray field 300 eV temperature. ablation pressure produced by...
The neutron spectrum from a cryogenically layered deuterium–tritium (dt) implosion at the National Ignition Facility (NIF) provides essential information about performance. From measured primary-neutron (13–15 MeV), yield (Yn) and hot-spot ion temperature (Ti) are determined. scattered (10–12 MeV) relative to Yn, down-scatter ratio, fuel areal density (ρR) These parameters have been diagnosed an unprecedented accuracy with suite of neutron-time-of-flight spectrometers magnetic recoil...
The diffusion of molecules through and between organic layers is a serious stability concern in electronic devices. In this work, the temperature-dependent molecular dopants small molecule hole transport observed. Specifically we investigate bilayer stacks used for (MeO-TPD) p-type (F4TCNQ C60F36) injection light emitting diodes collection electrodes photovoltaics. With use absorbance spectroscopy, photoluminescence neutron reflectometry, near-edge X-ray absorption fine structure are able to...
Abstract Organic bulk‐heterojunction solar cells are being developed as a low‐cost alternative to inorganic photovoltaics. A key step producing high‐efficiency devices is film curing using either heat or solvent atmosphere. All of the literature examining process have assumed that improvement morphology reason for increased filling factor, short‐circuit current density, and efficiency following treatment. We show in this article treatment causes donor polymer (P3HT) electrode (PEDOT:PSS) mix...
Sterile neutrinos are natural extensions to the standard model of particle physics and provide a possible portal dark sector. We report new search for existence sub-MeV sterile using decay-momentum reconstruction technique in decay $^{7}\mathrm{Be}$. The experiment measures total energy $^{7}\mathrm{Li}$ daughter atom from electron capture $^{7}\mathrm{Be}$ implanted into sensitive superconducting tunnel junction (STJ) quantum sensors. This first presents data single STJ operated at low...
Ga(1-x)In(x)N(y)As(1-y) is a promising material system for the fabrication of inexpensive "last-mile" optoelectronic components. However, details its atomic arrangement and relationship to observed optical properties not fully known. Particularly, blueshift emission wavelength after annealing. In this work, we use x-ray absorption fine structure study chemical environment around N atoms in before We find that as-grown molecular beam epitaxy consists nearly random distribution atoms, while...
First results from the analysis of neutron image data collected on implosions cryogenically layered deuterium-tritium capsules during 2011-2012 National Ignition Campaign are reported. The span a variety experimental designs aimed at increasing stagnation pressure central hotspot and areal density surrounding fuel assembly. Images neutrons produced by deuterium–tritium fusion reactions in presented, as well images that scatter dense compared with 1D 2D model predictions, consistency checked...
The National Ignition Facility has been used to compress deuterium-tritium an average areal density of ~1.0±0.1 g cm(-2), which is 67% the ignition requirement. These conditions were obtained using 192 laser beams with total energy 1-1.6 MJ and peak power up 420 TW create a hohlraum drive shaped profile, peaking at soft x-ray radiation temperature 275-300 eV. This pulse delivered series shocks that compressed capsule containing cryogenic radius 25-35 μm. Neutron images implosion estimate...
The Beryllium Electron capture in Superconducting Tunnel junctions (BeEST) experiment searches for evidence of heavy neutrino mass eigenstates the nuclear electron decay $^7$Be by precisely measuring recoil energy $^7$Li daughter. In Phase-III, BeEST has been scaled from a single superconducting tunnel junction (STJ) sensor to 36-pixel array increase sensitivity and mitigate gamma-induced backgrounds. Phase-III also uses new continuous data acquisition system that greatly increases...
Abstract The composition of polymer‐fullerene blends is a critical parameter for achieving high efficiencies in bulk‐heterojunction (BHJ) organic photovoltaics. Achieving the “right” materials distribution crucial device optimization as it greatly influences charge‐carrier mobility. effect vertical concentration profile spin‐coated BHJs on properties has stirred particularly vigorous debate. Despite available literature this subject, results are often contradictory and inconsistent, likely...
Neutron time-of-flight spectra from inertial confinement fusion experiments with tritium-filled targets have been measured at the National Ignition Facility. These represent a significant improvement in energy resolution and statistics over previous measurements, afford first definitive observation of peak resulting sequential decay through ground state (5)He low reaction energies E(c.m.) 100 </~ keV. To describe spectrum, we developed an R-matrix model that accounts for interferences...
Trivalent cerium ions form the luminescence centers in several important families of scintillation materials including rare earth oxyorthosilicates, pyrosilicates, and aluminates. When comparing experimentally determined properties cerium-doped scintillators to theoretical models mechanisms, there is often speculation regarding fraction total that exists radiative trivalent charge state (Ce/sup 3+/) rather than nonradiative tetravalent 4+/). Until now, however, no technique has been...
The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a Campaign diagnostic. WRF measures spectrum of protons from D-(3)He reactions in tuning-campaign implosions containing D (3)He gas; this work we report on first spectroscopy measurement NIF using WRFs. energy downshift 14.7-MeV is directly related total ρR through plasma stopping power. Additionally, shock yield measured, which metric final merged strength.
We present an experimental study of the time scales for various quasiparticle processes in a superconducting single photon spectrometer. Processes studied include recombination, diffusion, trapping, tunneling, and energy redistribution. Experiments were performed with double junction, imaging x-ray detector whose charge output provides measure energy. Time are extracted simple model values several parameters, including diffusion constant recombination time, found to differ from theoretical...