Greg P. Smestad, et al, Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses, Atlas/NIST Workshop on PV Materials Durability
December 5-6, 2017
National Institute of Standards and Technology, Gaithersburg, Maryland
https://www.nist.gov/el/mssd/agenda
http://www.surfacetreatments.it/thinfilms
Commissioning of the JLab Surface Impedance Characterization (SIC) System (Charles Reece - 20')
Speaker: Charles Reece - Jefferson Lab, Newport News (VA) USA | Duration: 20 min.
Abstract
Binping Xiao, Larry Phillips, and Charles Reece
A system for making direct calorimetric measurements of the surface resistance at 7.5 GHz of small samples of variously prepared superconducting surfaces has been commissioned at JLab. The flat, 50 mm diameter sample temperature is regulated independently of the balance of the TE011 sapphire-loaded cavity, enabling Rs and Δλ measurements from 2 K to Tc of the sample. Initial operation, limited by available rf power, has extended to Bpk of 18 mT. The calorimeter resolution is better than 10 nΩ, and the sampled surface area is ~ 0.8 cm2. The SIC has been commissioned with a bulk Nb sample, demonstrating excellent agreement with standard BCS characterizations. Initial application to SRF thin films has begun. We are eager to apply it to non-niobium materials. Preparations for a second generation with extended dynamic range have already begun.
Raman Spectroscopy is a non destructive chemical analysis technique which provides detailed information about chemical structure, crystallinity and molecular interactions. The raman effect involves scattering of light by molecules of gases, liquids, or solids. Raman Spectroscopy is sensitive to homo-nuclear molecular bonds. It is able to distinguish between single, double, and triple bonds between carbon atoms.Raman spectroscopy is the study of matter by the inelastic scattering of monochromatic
light. It has become a ubiquitous tool in modern spectroscopy, biophysics, microscopy, geochemistry, and analytical chemistry. In contrast to typical absorption or emission spectroscopy experiments, transitions among quantum levels of atoms or molecules are induced by the absorption or emission of photons (IR, visible, UV). In a typical Raman experiment, a polarized monochromatic light source (usually a laser) is focused into a sample, and the scattered light at 90 degree
to the laser beam is collected and dispersed by a high-resolution monochromator. The incident laser wavelength (chosen such that
the sample does not absorb, in ordinary Raman Spectroscopy) is fixed, and the scattered light is
dispersed and detected to obtain the frequency spectrum of the scattered light. The scattered light is very weak
(<10-7 of the incident power), so that monochromators with excellent straylight rejection and sensitive detectors are required. In a much rarer event (approximately 1 in 10million photons)Raman scattering occurs, which is an inelastic scattering process with a transfer of energy between the molecule and scattered photon. If the molecule gains energy from the photon during the scattering (excited to a higher
vibrational level) then the scattered photon loses energy and its wavelength increases which is called Stokes Raman scattering . Inversely, if the molecule loses energy by relaxing to alower vibrational level the scattered photon gains thecorresponding energy and its wavelength decreases;
which is called Anti-Stokes Raman scattering. • Quantum mechanically Stokes and Anti-Stokes areequally likely processes. However, with an ensemble of molecules, the majority of molecules will be in the ground vibrational level (Boltzmann distribution) and Stokes scatter is the statistically more probable process. As a result, the Stokes Raman scatter is always more intense than the anti-Stokes and for this
reason, it is nearly always the Stokes Raman scatter that is measured in Raman spectroscopy. Raman spectroscopy is used in chemistry to identify molecules and study chemical bonding and intramolecular bonds.In solid-state physics, Raman spectroscopy is used to characterize materials, measure temperature, and find the crystallographic orientation of a sample . In nanotechnology, a Raman microscope can be used to analyze nanowires to better understand their structures, and the radial breathing mode of carbon nanotubes is commonly used to evaluate their diameter.
Greg P. Smestad, et al, Optical Characterization of PV Glass Coupons and PV Modules Related to Soiling Losses, Atlas/NIST Workshop on PV Materials Durability
December 5-6, 2017
National Institute of Standards and Technology, Gaithersburg, Maryland
https://www.nist.gov/el/mssd/agenda
http://www.surfacetreatments.it/thinfilms
Commissioning of the JLab Surface Impedance Characterization (SIC) System (Charles Reece - 20')
Speaker: Charles Reece - Jefferson Lab, Newport News (VA) USA | Duration: 20 min.
Abstract
Binping Xiao, Larry Phillips, and Charles Reece
A system for making direct calorimetric measurements of the surface resistance at 7.5 GHz of small samples of variously prepared superconducting surfaces has been commissioned at JLab. The flat, 50 mm diameter sample temperature is regulated independently of the balance of the TE011 sapphire-loaded cavity, enabling Rs and Δλ measurements from 2 K to Tc of the sample. Initial operation, limited by available rf power, has extended to Bpk of 18 mT. The calorimeter resolution is better than 10 nΩ, and the sampled surface area is ~ 0.8 cm2. The SIC has been commissioned with a bulk Nb sample, demonstrating excellent agreement with standard BCS characterizations. Initial application to SRF thin films has begun. We are eager to apply it to non-niobium materials. Preparations for a second generation with extended dynamic range have already begun.
Raman Spectroscopy is a non destructive chemical analysis technique which provides detailed information about chemical structure, crystallinity and molecular interactions. The raman effect involves scattering of light by molecules of gases, liquids, or solids. Raman Spectroscopy is sensitive to homo-nuclear molecular bonds. It is able to distinguish between single, double, and triple bonds between carbon atoms.Raman spectroscopy is the study of matter by the inelastic scattering of monochromatic
light. It has become a ubiquitous tool in modern spectroscopy, biophysics, microscopy, geochemistry, and analytical chemistry. In contrast to typical absorption or emission spectroscopy experiments, transitions among quantum levels of atoms or molecules are induced by the absorption or emission of photons (IR, visible, UV). In a typical Raman experiment, a polarized monochromatic light source (usually a laser) is focused into a sample, and the scattered light at 90 degree
to the laser beam is collected and dispersed by a high-resolution monochromator. The incident laser wavelength (chosen such that
the sample does not absorb, in ordinary Raman Spectroscopy) is fixed, and the scattered light is
dispersed and detected to obtain the frequency spectrum of the scattered light. The scattered light is very weak
(<10-7 of the incident power), so that monochromators with excellent straylight rejection and sensitive detectors are required. In a much rarer event (approximately 1 in 10million photons)Raman scattering occurs, which is an inelastic scattering process with a transfer of energy between the molecule and scattered photon. If the molecule gains energy from the photon during the scattering (excited to a higher
vibrational level) then the scattered photon loses energy and its wavelength increases which is called Stokes Raman scattering . Inversely, if the molecule loses energy by relaxing to alower vibrational level the scattered photon gains thecorresponding energy and its wavelength decreases;
which is called Anti-Stokes Raman scattering. • Quantum mechanically Stokes and Anti-Stokes areequally likely processes. However, with an ensemble of molecules, the majority of molecules will be in the ground vibrational level (Boltzmann distribution) and Stokes scatter is the statistically more probable process. As a result, the Stokes Raman scatter is always more intense than the anti-Stokes and for this
reason, it is nearly always the Stokes Raman scatter that is measured in Raman spectroscopy. Raman spectroscopy is used in chemistry to identify molecules and study chemical bonding and intramolecular bonds.In solid-state physics, Raman spectroscopy is used to characterize materials, measure temperature, and find the crystallographic orientation of a sample . In nanotechnology, a Raman microscope can be used to analyze nanowires to better understand their structures, and the radial breathing mode of carbon nanotubes is commonly used to evaluate their diameter.
Research paper 1. UV dominant optical emission newly detected from radioisoto...home
IN A SINGLE RESEARCH PAPER all Six Fundamental Physics Discoveries in Nuclear Physics, X-ray physics, Atomic spectroscopy were reported in 2010 :
M.A.Padmanabha Rao,
UV dominant optical emission newly detected from radioisotopes and XRF sources,
Braz. J. Phy., 40, no 1, 38-46,2010.
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332010000100007
1. Radiation Trapping in O-RAFS
Ben Quinby Space Vehicles Scholar RVBY Dr. Nathan Lemke
Radiation Trapping
420 nm fluorescence radiation is resonant with the
background Rubidium vapor
Higher cell temperature makes a more efficient clock
Higher temperature leads to more capture events
Captured fluorescence is rarely released back as
420 nm light, leading to diminished fluorescence
readings
AF Relevance
Quantifying radiation trapping in O-RAFS will provide a
better understanding of how this may affect the quality of
the atomic clock. A higher stability clock will improve the
performance and resiliency of satellite-based navigation
systems.
Optical Rubidium Atomic Frequency Standard
(O-RAFS)
A simple optical clock built from off-the-shelf components
Short-term stability exceeds that of current clocks by 10x
No laser cooling
Minimal magnetic shielding
Small size, weight, and power
Summary
We can conclusively say that we have seen radiation
trapping in O-RAFS. With this data we should be able to
calculate the optimal temperature and size of the
rubidium vapor cell to maximize the clock stability per unit
of laser power.
The detection of red fluoresce for the servo feedback will
will be pursued further, as it does not suffer from the
effects of radiation trapping, allowing the vapor cell to be
operated at higher temperatures.
Figure 2: The error signal arises from modulating the
laser frequency across the atomic spectrum. The plots
are all scaled to match their ending values in order to
make meaningful comparisons.
Figure 3: Red and blue fluorescence plotted and scaled to
match values at 80°C. We can clearly see radiation
trapping of the blue fluoresce really start to dominate the
signal at around 100°C and above.
Figure 1: Energy levels and important transitions of
Rubidium in the O-RAFS experiment. The dotted line is
the virtual state which allows for the two photon
absorption. The blue 420 nm transition is the
fluorescence we typically detect. The 776 nm transition
is the red fluorescence investigated here.
Figure 4: O-RAFS experimental schematic. Retro-
reflecting the laser light yields a Doppler free spectrum.
Figure 5: O-RAFS experimental setup. The outer box is a
magnetic shield
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