This meeting abstract was removed due to the OA licensing requirements of this journal. The full abstract is listed here
:
https://www.svin.org/files/SVIN_2021_Abstracts_for_Web.pdf
Anodic aluminum oxide templates with pore diameter of 40nm and inter pore separation of 100nm are prepared by two step anodization in 0.3M oxalic acid solution. These templates are used to fabricate ...dc-deposited Co nanowires at different pH values of acidic bath. Continuous and densely packed nanowires having length ~8µm are observed. The hcp configuration appeared at moderate and high pH whereas both fcc and hcp phases are observed at low pH. However the crystallinity distorted at high pH due to formation of polycrystalline structure of cobalt nanowires. Alignment of easy-axis of nanowires can be tailored by varying pH of solution.
•Variation in the structure of dc deposited cobalt nanowires can be obtained by varying pH of acidic bath.•The hcp structure is stable at room temperature with low voltage deposition for electrodeposited Co nanowires. Co with fcc structure, is stable at temperatures above 422°C or at pH<3 with high potential.•The hcp (100) plane is obtained with pH~3.5 and (101) is stable at pH~5.5 due to variation in temperature inside the pores with respect to the pH.•Alignment of easy-axis of nanowires can be tailored by varying pH of solution.
The temperature dependence of the critical resolved shear stress (CRSS), τ
,
of ultra-pure tantalum single crystals (RRR ≥ 14000) observed below 250 K for a range of shear-strain rates
was analyzed ...within the framework of a kink-pair nucleation model of flow stress. The CRSS/strain-rate data follow the model formulation
, where
C
and
D
are positive constants, for each deformation temperature
T
in the range 78–250 K. Evaluation of the various slip-parameters of flow stress points to (211)
slip system responsible for the yielding of ultra-pure tantalum single crystals in the so-called stress/temperature regime III (
T
< 250 K). The value of the pre-exponential factor
in the Arrhenius-type equation for the shear-strain rate
is found to be of the order of 10
5
s
−1
, which is substantially lower than that
determined in the stress/temperature regime II (250–400 K) and contradicts the assumption invariably made in most of the theoretical models of flow stress that
is a constant over a wide temperature range.
LUX-ZEPLIN (LZ) is a second-generation direct dark matter experiment with spin-independent WIMP-nucleon scattering sensitivity above
1.4
×
10
-
48
cm
2
for a WIMP mass of
40
GeV
/
c
2
and a
1000
days
...exposure. LZ achieves this sensitivity through a combination of a large
5.6
t
fiducial volume, active inner and outer veto systems, and radio-pure construction using materials with inherently low radioactivity content. The LZ collaboration performed an extensive radioassay campaign over a period of six years to inform material selection for construction and provide an input to the experimental background model against which any possible signal excess may be evaluated. The campaign and its results are described in this paper. We present assays of dust and radon daughters depositing on the surface of components as well as cleanliness controls necessary to maintain background expectations through detector construction and assembly. Finally, examples from the campaign to highlight fixed contaminant radioassays for the LZ photomultiplier tubes, quality control and quality assurance procedures through fabrication, radon emanation measurements of major sub-systems, and bespoke detector systems to assay scintillator are presented.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Giant magnetoresistance (GMR) behavior in electrodeposited NFe/Cu/Ni multilayered (ML) structures is investigated as a function of non-magnetic (Cu) and ferromagnetic (Fe and Ni) layers' thicknesses. ...Detailed structural and magnetic analyses of the ML structures are studied before looking into the GMR behavior. Structural analyses reveal that all peaks are well matched with Ni (face-centered cubic) being the top most layer during ML deposition. Shifting of preferred orientation, between (220) and (111) planes, is observed with the thickest layer of copper spacer. Refined structural parameters are calculated and details of fittings are discussed with reference to layer thicknesses. Crystallite size, dislocation density, stacking fault probability, and strain all show oscillatory behavior with variation in thicknesses. Magnetic behavior shows strong dependence of magnetization on thickness of each layer. Saturation magnetization (<inline-formula> <tex-math notation="LaTeX">M_{s}) </tex-math></inline-formula> increases up to a value of 10.12 emu/cm 3 with increasing Fe and Ni layer thicknesses. Whereas, oscillatory behavior of magnetization is observed with variation in Cu layer thickness. Magnetoresistance (MR) measurements show oscillatory GMR behavior as a function of intervening layer thickness. Highest value of GMR ~12% is observed at a Cu layer thickness of 9.6 nm. Structural, magnetic, and MR properties of NFe/Cu/Fe are observed on the basis of variation of thicknesses of non-magnetic (Cu) and ferromagnetic (Fe and Ni) layers. It is observed that layer thicknesses play a dominant effect on the nature (i.e., oscillatory) and on the value of GMR.
•One DLC and three multilayer DLC:Mo thin films were deposited on Si substrate.•Surface roughness and Urbach energy increase linearly as Mo content increases.•Refractive index and optical band gap ...decrease exponentially with Mo addition.•Electrical resistivity decreases exponentially as Mo content increases.•Crystallite size of Mo particles increases exponentially with Mo concentration.
Off-axis pulsed laser deposition technique was used to deposit a diamond-like carbon (DLC) thin film and three multilayer DLC:Mo thin films of various compositions on p-type Si (111) substrate at room temperature keeping the DLC content constant. Excimer laser was used to ablate graphite and Mo targets in a vacuum of ∼10−5mbar, whereas the p-type Si (111) substrate was placed downside the target at a distance of 1cm in off-axis PLD geometry. Morphological, structural, optical, and electrical characteristics of the deposited thin films were then investigated. SEM images of the thin films show that surface roughness increases as Mo content in the film increases. XRD patterns of DLC:Mo thin films rule out any carbide formation. Both crystallite size of Mo particles and film thickness increase whereas microstrain decreases with the increase in Mo content. Moreover, both refractive index and indirect optical band gap decrease exponentially while Urbach energy increases linearly with the increase in Mo content. Electrical resistivity of the thin films has been found to follow an exponential decay with the increase in Mo content in multilayer DLC:Mo thin films.
We report the use of pulsed laser deposition (PLD) to grow manganese oxide thin films at a fixed low oxygen pressure at different temperatures on silicon (1 0 0) substrates. Structural properties of ...the thin films were examined using x-ray diffraction and Fourier transform infrared spectroscopy. Surface morphology and topography of the films was determined using atomic force microscopy and optical microscopy, while optical properties of the thin films were studied using spectroscopic ellipsometry. It was found that PLD is a convenient technique to deposit different phases of manganese oxide by tuning the deposition temperature. All measured physical properties such as morphology, topography, crystallite size, and optical band gap were clearly dependent on the substrate temperature chosen.
KrF⁎ excimer laser (248nm wavelength) is tightly focused on strontium hexa ferrite (SrFe12O19) to deposit its thin films on glass. Thin films were deposited at room temperature (25°C) and at 350°C in ...the absence and presence of the externally applied (0.5T) magnetic field in transverse direction. The experiments were performed under vacuum ∼10−6Torr. All deposited films were characterized for crystallographic structure, surface morphology, magnetic properties, and optical properties using X-Ray Diffractometer (XRD), Scanning electron microscopy (SEM), Vibrating sample magnetometer (VSM) and Spectroscopic ellipsometry (SE). The results thus obtained show that magneto-optical properties of deposited thin films have been enhanced in the presence of magnetic field.
► Thin films of strontium hexa ferrite (SrFe12O19)were deposited on glass. ► The external magnetic field was applied at different temperatures. ► The experiments were performed under vacuum ∼10−6Torr. ► Structuctural, morphological, magnetic and optical properties are investigated. ► Magneto-optical properties of thin films are enhanced in the presence of magnetic field.
The effect of laser-irradiance on the surface morphology and laser induced breakdown spectroscopy of zinc has been investigated by employing Nd:YAG laser (wavelength λ = 1064 nm, pulse duration ...t ~ 10 ns, and repetition rate = 10 Hz) under ambient environment of argon at a pressure of 20 Torr. For this purpose, zinc targets were exposed to various laser irradiances ranging from 13 GW/cm2 to 100 GW/cm2. Scanning electron microscope analysis has been performed to analyze the surface modification of irradiated zinc targets. Scanning electron microscope analysis revealed the formation of various kinds of structures such as ripples, cones, cavities, and wave like ridges at the center and peripheral regions of ablated zinc. In the central ablated region with increasing laser irradiance, the growth of distinct and well defined ripples is observed. Further increase in irradiance makes the appearance of these ripples diffusive and narrow. In order to correlate the plasma parameters with the surface modification, laser induced breakdown spectroscopy analysis has also been performed. The electron temperature and number density of zinc plasma have been evaluated at various laser irradiances. For both plasma parameters, an increasing trend up to a certain value of laser irradiance is observed which is due to enhanced energy deposition. Afterword a decreasing trend is achieved which is attributed to the shielding effect. With further increase in irradiance a saturation stage comes and almost no change in plasma parameters is observed. This saturation is explainable on the basis of the formation of a self-regulating regime near the target surface. A strong correlation between surface modification and plasma parameters is established.
The power range channels of nuclear reactors are linear, which cover only one decade, so they do not show any response during the startup and intermediate range of the reactor operation. So, there is ...no prior indication of the channels during startup and intermediate operating ranges in case of failure of the detectors or any other electronic fault in the channel. A new reliable nuclear channel has been developed for reactor power measurement, which can be programmed to work in the logarithmic mode during startup and intermediate range of operation, and as the reactor enters into the power range, the channel automatically switches to the linear mode of operation. The log-linear mode operation of the channel provides wide-range monitoring, which improves the self-monitoring capabilities and the availability of the reactor. The channel can be programmed for logarithmic, linear, or log-linear mode of operation. In the log-linear mode, the channel operates partially in log mode and automatically switches to linear mode at any preset point. The channel was tested at Pakistan Research Reactor-1 (PARR-1), and the results were found in very good agreement with the designed specifications. This paper presents design and construction of the channel and field test results.
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