Theoretical studies of in‐situ rock density determinations using underground cosmic‐ray muon intensity measurements with application in mining geophysics

Geophysics ◽  
1979 ◽  
Vol 44 (9) ◽  
pp. 1549-1569 ◽  
Author(s):  
L. Malmqvist ◽  
G. Jönsson ◽  
K. Kristiansson ◽  
L. Jacobsson
Keyword(s):  
Theoretical Calculations ◽  
Scintillation Counter ◽  
Cosmic Ray ◽  
Massive Sulfide ◽  
Rock Density ◽  
Density Anomaly ◽  
Intensity Measurements ◽  
Muon Intensity ◽  
Change In Mean

The feasibility of in‐situ rock density determinations by means of subsurface cosmic‐ray muon intensity measurements is based on theoretical calculations for two hypothetical scintillation counter telescopes: one is intended for registration in a gallery and the other is intended for use in narrow boreholes. It is shown that it is possible to measure the mean density of the rock traversed by the muons by measuring the muon intensity. The sensitivity of the method is favorable—a 1 percent change in mean rock density corresponds to a change of about 3 percent in the counting rate. A possible use of cosmic‐ray muon technique is the localization of an anomalous density distribution in overlying rock. A characteristic minimum registration time to detect a certain density anomaly varies from a few hours to about 10 days, depending on the geologic situation and the depth and design of the detector. The device is found to be most applicable for massive sulfide and iron exploration. This tecnique provides some new possibilities. A certain spatial resolution can be achieved at the expense of the registration time, and the overlying rock can, to some extent, be investigated in different directions from one point of observation. The method seems to be useful down to depths of approximately 600 m for the gallery application and 400 m for the borehole application. However, these limits are a consequence of the size of the detector, the size and density contrast of the target, and the maximum registration time accepted for each observation.

scholarly journals Atmospheric effects of the cosmic-ray mu-meson component

2018 ◽  
Vol 4 (3) ◽  
pp. 76-82 ◽  
Author(s):  
Валерий Янчуковский ◽  
Valery Yanchukovsky ◽  
Василий Кузьменко ◽  
Vasiliy Kuzmenko
Keyword(s):  
Experimental Data ◽  
Factor Analysis ◽  
Cosmic Rays ◽  
Theoretical Calculations ◽  
Cosmic Ray ◽  
Atmospheric Effects ◽  
Atmospheric Component ◽  
Significant Temperature ◽  
Muon Intensity ◽  
Barometric Effect

Variations in the intensity of cosmic rays observed in the depth of the atmosphere include the atmospheric component of the variations. Cosmic-ray muon telescopes, along with the barometric effect, have a significant temperature effect due to the instability of detected particles. To take into account atmospheric effects in muon telescope data, meteorological coefficients of muon intensity are found. The meteorological coefficients of the intensity of muons recorded in the depth of the atmosphere are estimated from experimental data, using various methods of factor analysis. The results obtained from experimental data are compared with the results of theoretical calculations.

scholarly journals Atmospheric effects of the cosmic-ray mu-meson component

2018 ◽  
Vol 4 (3) ◽  
pp. 95-102
Author(s):  
Валерий Янчуковский ◽  
Valery Yanchukovsky ◽  
Василий Кузьменко ◽  
Vasiliy Kuzmenko
Keyword(s):  
Experimental Data ◽  
Factor Analysis ◽  
Theoretical Calculations ◽  
Cosmic Ray ◽  
Atmospheric Effects ◽  
Atmospheric Component ◽  
Coeffi Cients ◽  
Significant Temperature ◽  
Muon Intensity ◽  
Barometric Effect

Variations in the intensity of cosmic rays observed in the depth of the atmosphere include the atmospheric component of the variations. Cosmic-ray muon telescopes, along with the barometric effect, have a significant temperature effect due to the instability of detected particles. To take into account atmospheric effects in muon telescope data, meteorological coeffi-cients of muon intensity are found. The meteorological coefficients of the intensity of muons recorded in the depth of the atmosphere are estimated from experi-mental data, using various methods of factor analysis. The results obtained from experimental data are com-pared with the results of theoretical calculations.

scholarly journals Cosmic-Ray Driven Outflows to Mpc Scales from L* Galaxies

2020 ◽  
Author(s):  
Philip F Hopkins ◽  
T K Chan ◽  
Suoqing Ji ◽  
Cameron B Hummels ◽  
Dušan Kereš ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Plane Layer ◽  
Equilibrium Density ◽  
Pressure Gradients ◽  
Low Velocity ◽  
Star Forming ◽  
Stellar Feedback ◽  
Massive Halos ◽  
Halo Masses

Abstract We study the effects of cosmic rays (CRs) on outflows from star-forming galaxies in the circum and inter-galactic medium (CGM/IGM), in high-resolution, fully-cosmological FIRE-2 simulations (accounting for mechanical and radiative stellar feedback, magnetic fields, anisotropic conduction/viscosity/CR diffusion and streaming, and CR losses). We showed previously that massive (Mhalo ≳ 1011 M⊙), low-redshift (z ≲ 1 − 2) halos can have CR pressure dominate over thermal CGM pressure and balance gravity, giving rise to a cooler CGM with an equilibrium density profile. This dramatically alters outflows. Absent CRs, high gas thermal pressure in massive halos “traps” galactic outflows near the disk, so they recycle. With CRs injected in supernovae as modeled here, the low-pressure halo allows “escape” and CR pressure gradients continuously accelerate this material well into the IGM in “fast” outflows, while lower-density gas at large radii is accelerated in-situ into “slow” outflows that extend to >Mpc scales. CGM/IGM outflow morphologies are radically altered: they become mostly volume-filling (with inflow in a thin mid-plane layer) and coherently biconical from the disk to >Mpc. The CR-driven outflows are primarily cool (T ∼ 105 K) and low-velocity. All of these effects weaken and eventually vanish at lower halo masses (≲ 1011 M⊙) or higher redshifts (z ≳ 1 − 2), reflecting the ratio of CR to thermal+gravitational pressure in the outer halo. We present a simple analytic model which explains all of the above phenomena. We caution that these predictions may depend on uncertain CR transport physics.

Rock density from borehole gravity surveys

Geophysics ◽  
1983 ◽  
Vol 48 (3) ◽  
pp. 341-356 ◽  
Author(s):  
T. R. LaFehr
Keyword(s):  
Bulk Density ◽  
Apparent Density ◽  
Density Change ◽  
Large Radius ◽  
Rock Density ◽  
Density Anomaly ◽  
Poisson Jump ◽  
The Difference ◽  
Well Data ◽  
Station Location

The borehole gravity meter (BHGM) is recognized as an important logging tool for obtaining formation bulk density. In general, however, the difference between two gravity observations vertically separated in a well leads to an apparent and not the actual bulk density. BHGM‐derived apparent densities are equal to the formation bulk densities when the instrument passes through beds which are horizontal, infinitely extended laterally, uniformly thick, and constant in density. For many applications, departures from these assumed conditions are so slight that their effects can be ignored, and the BHGM essentially yields bulk density with a large radius of investigation. In the presence of anomalous masses, significant distortion in formation bulk density is possible. The apparent density anomaly produced in the well by an elongated, offset density contrast is proportional to the angle subtended by the density‐change interface. For a density‐change boundary having circular symmetry with respect to the well, the apparent density anomaly at the center of the bed is proportional to the sine of the subtended angle. Because the distortion in bulk density is the same above a horizontal boundary as it is just below (in the limit, at the boundary, for a normally incident well), an abrupt change in apparent density is equal to the real density change at the boundary. This change in density, termed “the Poisson jump,” is independent of geometry; our ability to measure it, however, is a function of station location with respect to the geologic bodies. Two methods are suggested for obtaining bulk densities from BHGM apparent densities: (1) by obtaining two stations just outside as well as just within the zone of interest, the Poisson jump can be approximated and added to an independent density source (e.g., the gamma‐gamma log), and (2) the apparent density anomaly within the formation of interest can be derived by modeling (perhaps based on seismic or well data) and added to the BHGM‐determined densities. Thinner beds can be studied with the BHGM than generally believed, even with much greater station spacing.

scholarly journals Phase Formation during Solidification of Mg-Nd-Zn Alloys: An In Situ Synchrotron Radiation Diffraction Study

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1637 ◽  
Author(s):  
Domonkos Tolnai ◽  
Tungky Subroto ◽  
Serge Gavras ◽  
Ricardo Buzolin ◽  
Andreas Stark ◽  
...  
Keyword(s):  
Rare Earth ◽  
Synchrotron Radiation ◽  
Diffraction Study ◽  
Phase Formation ◽  
Theoretical Calculations ◽  
Alloy System ◽  
Zn Addition ◽  
Synchrotron Radiation Diffraction ◽  
Zn Alloys

Mg-4Nd base alloys with Zn additions of 3, 5 and 8 wt % were investigated with in situ synchrotron radiation diffraction during solidification. This method enabled the investigation of phase formation and transformation in the alloys. The diffraction results were supported with TEM observations on the as-solidified samples. The results show the effect of increased Zn addition on stabilizing the Mg3RE phase (RE—rare earth). The experimental results agree only partially with the theoretical calculations indicating the need to improve the existing thermodynamic database on the alloy system.

scholarly journals A Novel Lithium Foil Cosmic-Ray Neutron Detector for Measuring Field-Scale Soil Moisture

2021 ◽  
Vol 3 ◽  
Author(s):  
Andres Patrignani ◽  
Tyson E. Ochsner ◽  
Benjamin Montag ◽  
Steven Bellinger
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Atmospheric Pressure ◽  
Lower Cost ◽  
Cosmic Ray ◽  
Absolute Difference ◽  
Atmospheric Conditions ◽  
Volumetric Soil Water Content ◽  
The Mean

During the past decade, cosmic-ray neutron sensing technology has enabled researchers to reveal soil moisture spatial patterns and to estimate landscape-average soil moisture for hydrological and agricultural applications. However, reliance on rare materials such as helium-3 increases the cost of cosmic-ray neutron probes (CRNPs) and limits the adoption of this unique technology beyond the realm of academic research. In this study, we evaluated a novel lower cost CRNP based on moderated ultra-thin lithium-6 foil (Li foil system) technology against a commercially-available CRNP based on BF3 (boron trifluoride, BF-3 system). The study was conducted in a cropped field located in the Konza Prairie Biological Station near Manhattan, Kansas, USA (325 m a.s.l.) from 10 April 2020 to 18 June 2020. During this period the mean atmospheric pressure was 977 kPa, the mean air relative humidity was 70%, and the average volumetric soil water content was 0.277 m3 m−3. Raw fast neutron counts were corrected for atmospheric pressure, atmospheric water vapor, and incoming neutron flux. Calibration of the CRNPs was conducted using four intensive field surveys (n > 120), in combination with continuous observations from an existing array of in situ soil moisture sensors. The time series of uncorrected neutron counts of the Li foil system was highly correlated (r2 = 0.91) to that of the BF-3 system. The Li foil system had an average of 2,250 corrected neutron counts per hour with an uncertainty of 2.25%, values that are specific to the instrument size, detector configuration, and atmospheric conditions. The estimated volumetric water content from the Li foil system had a mean absolute difference of 0.022 m3 m−3 compared to the value from the array of in situ sensors. The new Li foil detector offers a promising lower cost alternative to existing cosmic-ray neutron detection devices used for hectometer-scale soil moisture monitoring.

scholarly journals Dynamically tuned non-classical light emission from atomic defects in hexagonal boron nitride

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Snežana Lazić ◽  
André Espinha ◽  
Sergio Pinilla Yanguas ◽  
Carlos Gibaja ◽  
Félix Zamora ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Information Technologies ◽  
Light Emission ◽  
Hexagonal Boron Nitride ◽  
Theoretical Calculations ◽  
Optical Emission ◽  
Spectral Tuning ◽  
Spectral Detection ◽  
On Chip

Abstract Luminescent defects in hexagonal boron nitride (h-BN) have recently emerged as a promising platform for non-classical light emission. On-chip solutions, however, require techniques for controllable in-situ manipulation of quantum light. Here, we demonstrate the dynamic spectral and temporal tuning of the optical emission from h-BN via moving acousto-mechanical modulation induced by stimulated phonons. When perturbed by the propagating acoustic phonon, the optically probed radiative h-BN defects are periodically strained and their sharp emission lines are modulated by the deformation potential coupling. This results in an acoustically driven spectral tuning within a 2.5-meV bandwidth. Our findings, supported by first-principles theoretical calculations, reveal exceptionally high elasto-optic coupling in h-BN of ~50 meV/%. Temporal control of the emitted photons is achieved by combining the acoustically mediated fine-spectral tuning with spectral detection filtering. This study opens the door to the use of sound for scalable integration of h-BN emitters in nanophotonic and quantum information technologies.

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