Canadian Journal of Physics

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Applications of Groundwater Helium

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Groundwater age dating with the tritium-helium (3H/3He) method has become a powerful The reproducibility of the 3He/4He ratio and 4He, Ne, Ar, Kr and Xe.

A refrigerator of the described kind is known from the article “Continuous cooling in the millikelvin range”, published in Philips Technical Review 36, , No. The superleak therein forms part of a fountain pump which furthermore comprises a second superleak, a heating element and a capillary. Superfluid 4He is extracted from the vaporization chamber and is supplied to the second mixing chamber by the fountain pump. The superfluid lie – reaches the vaporization chamber again via the first mixing chamber.

Stopping can be simply effected by setting a valve in the e gas supply of the machine which is at room temperature to the closed position. Due to the interruption of the flow of concen-trated e to the mixing chamber, the transport of heat to the mixing ehamber is reduced and the temperature therein deereases. As long as eoneentrated 3He is present in the mixing ehamber, the lower eooling temperature ean be main-tained. A dilution refrigerator comprising two mixing ehambers whieh are arranged at different levels and whieh are intereonneeted via a narrow duct offers the advantage for single-shot experiments that a machine of this kind ean temporarily produee eooling temperatures which are even lower than those produced by the macIline comprising only a single mixing chamber.

As a result, a single-shot experiment can be performed at a lower temperature and usually for a longer period of time in the machine comprising two mixing chambers than in the machine comprising one mixing chamber. The cooling of the upper mixing chamber, how-ever, is a problem in the machine comprising two mixing chambers. A single-shot experiment can be started only after such a long waiting period, if it is to be prevented that part of the cold production available for the single-shot is used for the cooling of the upper mixing chamber.

The latter means a substantial reduction of the time during which the lowest cooling temperature for the single-shot experiment in the upper mixing chamber can be maintained. Moreover, in the case of a comparatively high heat load from the object to be cooled, there is a risk that the desired low value of the cooling temperature is not reached.

Jürgen Sültenfuß

Author s : Stephen W. Parman corresponding author [1, 3]; Mark D. Kurz [2]; Stanley R. Hart [2]; Timothy L.

Accurate determination of the absolute 3He/4He ratio of a synthesized helium standard of helium isotopes, such as tritium-3He dating, surface-exposure.

This summary serves as the basis for the extraction of the alpha particle charge radius from the muonic helium Lamb shift measurements at the Paul Scherrer Institute, Switzerland. Individual theory contributions needed for a charge radius extraction are compared and compiled into a consistent summary. The influence of the alpha particle charge distribution on the elastic two-photon exchange is studied to take into account possible model-dependencies of the energy levels on the electric form factor of the nucleus.

We also discuss the theory uncertainty which enters the extraction of the 3 He— 4 He isotope shift from the muonic measurements. The theory uncertainty of the extraction is much smaller than a present discrepancy between previous isotope shift measurements. We also discuss the theory uncertainty which enters the extraction of the 3He—4He isotope shift from the muonic measurements.

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CA1045841A – 3he-4he dilution refrigerator – Google Patents

This site is using cookies to collect anonymous visitor statistics and enhance the user experience. Science Classification details. Abstract: Ernest Rutherford received the Nobel Prize for the discovery that radioactivity is a product of the spontaneous disintegration of a radioactive element the parent into another element the daughter. He soon realised that if the decay rate is known, this system can be used to determine the age of geological materials.

tion of noble-gas isotopes (3He, 4He, 21Ne, and. 40Ar), where measured concentrations in ground- waters were found to be in excess of solubility equilibrium.

Within a narrow temperature window, the air value in our experimental set up with pure quartz glass can range from about 2. When plotted versus temperature, the narrow 3 He net partial pressure peak reveals at least three sharper embedded peaks that may be quantized vibrational entrance states in quartz glass which are temperature specific. This discovery has implications for relatively low-energy industrial enrichment of scarce 3 He from natural sources on Earth, and for radiogenic and cosmogenic helium dating assumptions in natural glasses.

Helium is known to diffuse through glass as a function of temperature, pressure, and purity of the silica glass matrix 1 — 3. The fractionation of the 3 He isotope of helium in glass relative to its heavier and far more abundant isotope, 4 He, is less well understood. Earlier work by Shelby 5 found that the diffusivity isotope ratio for this pair in vitreous silica was as high as 1.

Quantum tunneling e. Experiments were conducted on a compact, elongate vacuum apparatus described in the Methods Fig. The results presented herein were recorded throughout a typical heating cycle, e. The trends of a typical, repeatable static lab air heat ramp are shown in Fig.

Ultra-low temperature installation

Measured He ages ranged from 8 to 61 Ma, and were reproducible to better than a few percent despite very large variations in [U] and [Th]. In all samples with internal stratigraphy or independent age constraints, the He ages honored the expected relationships. These data demonstrate that internally consistent He ages can be obtained on goethite, but do not prove quantitative 4He retention.

To assess possible diffusive He loss, stepped-heating experiments were performed on two goethite samples that were subjected to proton irradiation to produce a homogeneous distribution of spallogenic 3He. The 3He release pattern indicates the presence of at least two diffusion domains, one with high helium retentivity and the other with very low retentivity at Earth surface conditions.

Diffusive loss of 3He from the high retentivity domain is independent of the macroscopic dimensions of the analyzed polycrystalline aggregate, so probably represents diffusion from individual micrometer-size goethite crystals.

3He/4He ratios in well gases and CO2 springs range from to RA and Marty, ) and dating natural gas and groundwater resources (Zhou and.

NSF MRI Award Abstract: This project will establish a laboratory with state-of-the-art instruments for measuring noble gases in rock, mineral, and water samples, for geochronologic and geochemical studies in Earth, planetary, and environmental science. The facility will enable a wide variety of scientific studies by researchers and students at the University of Arizona and collaborating institutions. Some of the primary goals of these studies will be: 1 to investigate the timing and rates of geologic events and processes using radioisotopic dating, including faulting, magmatism, and erosion, 2 to characterize the behavior of noble gases in minerals to understand the material properties of natural crystals, and 3 to trace the movement and evolution of groundwater and other fluids in the Earth’s subsurface.

This project will also enable hands-on research training for students who will use the instruments and laboratory, helping them develop the quantitative and technical skills and experience for Earth, planetary, and environmental science. The centerpiece of the laboratory will be a new multi-collector gas-source sector mass spectrometer and sample introduction equipment including devices for extracting gases using resistance furnace and laser heating, crushing of fluid-inclusions, and exsolution from fluids.

State of the art high-resolution, high-sensitivity, and multi-collection capabilities of the mass spectrometer will enable simultaneous measurement of all isotopes of argon and neon, and helium will be measured by peak-hopping. In addition to serving researchers and students at the University of Arizona, Utah State University, and University of Texas El Paso, the facility will also provide analytical services and research experience opportunities for collaborators at a variety of institutions, including universities and liberal arts colleges, through analyses and workshops for diverse cohorts of students.

4He/3He laser microprobe analysis: a disruptive new technology for in-situ U-Th-He thermochronology

The stereomicroscopes have both transmitted polarized and reflected light capabilities. These morphometric values are subsequently imported into a LabView routine to calculate the alpha-ejection correction. Laser continuous-mode Nd-YAG lasers for total fusion He laser extraction, ideal for single-crystal work see House et al. The UT extraction line components and valves are fully interfaced with a central computer and are fully automated using LabView software. The 3He spiking, cryogenic trap temperature cycling, and mass spectrometric analysis of samples, gas standards, and blanks are fully computer controlled.

On extraction line 1, the laser heating of samples is controlled through a feedback loop using a video capture card allowing for continuous computerized adjustment of the laser output power for even heating.

While the ratio of 3He and 4He of the HESJ was prev. such as tritium-3He dating, surface-exposure age determination based on cosmogenic.

Handbook of Environmental Isotope Geochemistry pp Cite as. Helium abundance and isotope variations have widespread application in groundwater-related studies. This stems from the inert nature of this noble gas and the fact that its two isotopes — helium-3 and helium-4 — have distinct origins and vary widely in different terrestrial reservoirs.

In this review, we present a guide to how groundwater He is collected from aquifer systems and quantitatively measured in the laboratory. We then illustrate the approach of resolving the measured He characteristics into its component structures using assumptions of endmember compositions. This is followed by a discussion of the application of groundwater He to the types of topics mentioned above using case studies from aquifers in California and Australia. Finally, we present possible future research directions involving dissolved He in groundwater.

We thank Mark Baskaran for the invitation to contribute this review chapter.

AlbaNova/Nordita Colloquium 2011-11-10. Eunseong Kim “Supersolidity in Helium”