Status and new developments in field portable geochemical techniques and on-site technologies for mineral exploration

International audienceThere is an ongoing need to be innovative with the way we undertake mineral exploration. Recent technological advances that have enabled successful mineral exploration include on-site or portable instruments, on-site laboratory technologies, various core scanners, and technologies for fluid analysis. Portable or field technologies such as pXRF, pXRD, pNIR-SWIR, µRaman, and LIBS, aid in obtaining chemical and mineralogical information. Spectral gamma tools, a well-known technology, recently took advantage of improved ground and airborne (drone) instruments, to complement hyperspectral imagery. Novel, groundbreaking technology Lab-at-Rig®, was developed by CSIRO, Imdex and Olympus at the Deep Exploration Technologies CRC, and is currently being retrofitted to diamond drilling. Cuttings are separated from drilling fluids in a Solid Removal Unit (SRU), producing one meter composite mud which is sub-sampled, dried and analyzed by both X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) sensors that deliver the chemistry and mineralogy of a sample, respectively. These data are automatically uploaded to a cloud-based storage platform and subjected to a range of statistical analyses with results returned to the geologist in a matter of seconds, allowing decisions to be made in near real time. At a mine site, core scanners become a useful tool to analyse meters of core as it is being drilled. Core scanners include hyperspectral and XRF systems, such as Corescan, HyLogger and Minalyzer, for example. Fluid analyses are not as common as analyses of solid materials, but there are advances in such technologies as ASV, polarography, and ion exchange electrodes aiming for analysis of commodity or environmentally important elements. With all available portable, field and on-site technologies it is now possible to collect data at the exploration site or while drilling. Certainly, field and on-site analyses cannot yet compete with laboratory analyses in terms of sensitivity, precision and accuracy due to compromises in sample preparation, instrument performance and work environment. However, field and on-site results must only achieve the level of confidence expected from the decision. Most mineral exploration decisions are based on flexible thinking rather than on a pre-set framework of investigations. One of the key benefits of real-time analyses, or short delay analyses (less than a day) is the possibility to adjust sampling plans, test hypotheses based on ongoing results, and make fast decisions on the exploration process-especially drilling and sampling. This is particularly important for remote locations, where sample logistics to the laboratory may become long and demanding

Fermi Detection of the Pulsar Wind Nebula HESS J1640-465

We present observations of HESS J1640-465 with the Fermi-LAT. The source is detected with high confidence as an emitter of high-energy gamma-rays. The spectrum lacks any evidence for the characteristic cutoff associated with emission from pulsars, indicating that the emission arises primarily from the pulsar wind nebula. Broadband modeling implies an evolved nebula with a low magnetic field resulting in a high gamma-ray to X-ray flux ratio. The Fermi emission exceeds predictions of the broadband model, and has a steeper spectrum, possibly resulting from a distinct excess of low energy electrons similar to what is inferred for both the Vela X and Crab pulsar wind nebulae.Comment: 6 pages, 5 figures, accepted for publication in Ap

Introduction: New developments in field portable geochemical techniques and site technologies and their place in mineral exploration.

International audienceThere is an ongoing need to be innovative with the way we undertake mineral exploration. Recent technological advances that have enabled successful mineral exploration include on-site or portable instruments, on-site laboratory technologies, various core scanners, and technologies for fluid analysis. Portable or field technologies such as pXRF, pXRD, pNIR-SWIR, µRaman, and LIBS, aid in obtaining chemical and mineralogical information. Spectral gamma tools, a well-known technology, recently took advantage of improved ground and airborne (drone) instruments, to complement hyperspectral imagery. Novel, groundbreaking technology Lab-at-Rig®, was developed by CSIRO, Imdex and Olympus at the Deep Exploration Technologies CRC, and is currently being retrofitted to diamond drilling. Cuttings are separated from drilling fluids in a Solid Removal Unit (SRU), producing one meter composite mud which is sub-sampled, dried and analyzed by both X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) sensors that deliver the chemistry and mineralogy of a sample, respectively. These data are automatically uploaded to a cloud-based storage platform and subjected to a range of statistical analyses with results returned to the geologist in a matter of seconds, allowing decisions to be made in near real time. At a mine site, core scanners become a useful tool to analyse meters of core as it is being drilled. Core scanners include hyperspectral and XRF systems, such as Corescan, HyLogger and Minalyzer CS, for example. Fluid analyses are not as common as analyses of solid materials, but there are advances in such technologies as ASV, polarography, and ion exchange electrodes aiming for analysis of commodity or environmentally important elements. In this session we will introduce some techniques which appeared since 2007 or underwent major progress and discuss their benefits, challenges and pitfalls, why use them and what to expect from them. WHY USING FIELD TECHNIQUES, WHAT TO EXPECT FROM THEM Field portable technologies have seen rapid development over the past two decades, and especially in the last one. This is the result of recent technology advances that made on-site analysis possible and a credible alternative to laboratory work. We provide here a review of the main technologies involved. However, application of field technologies was slower in the more regulated exploration industry because there were quality compromises compared with conventional laboratory technologies, and therefore the same accuracy was not achievable initially. By offering analytical results on the spot, in almost real time, on-site technologies fit the increasing needs of exploration teams for fast information that provides decision making support during field work and drilling operations, and sample screening before laboratory requests. The gain in time and flexibility, even without any consideration of lower analytical costs, has a significant impact on the efficiency and cost-effectiveness of field operations, especially in remote areas. For instance, field analyses allow the selection of the most promising formations (Gałuszka et al., 2015, Zhang et al, 2017), stream or soil areas, and to focus immediately on potential targets. At a drill site, they help the geologists to identify target formations, to sample mineralised sections more precisely, and to stop drilling when necessary. Benefits are therefore expected for field costs and the length of operations. But the most important benefits are for exploration efficiency, and for improved chances to hit targets, due to continuous feedback of information. SOME TECHNIQUES WHICH APPEARED SINCE 2007 OR UNDERWENT MAJOR PROGRESS Analytical technologies designed for the laboratory are increasingly adapted for on-site use, in order to address mineral exploration needs for faster or more efficient decision making (Lemiere, 2015). This includes elemental and mineralogical solids analysis, water analysis, and other more integrated strategies. The scope of this presentation covers handheld instruments, able to operate in the field, and site portable instruments, able to operate at remote sites, with limited logistics. All should provide decision-making results within minutes or on the same day as sampling and analysis. The fast evolution of technology implies that many of them were far less advanced or even non-existent for Exploration'07

TDI noises transfer functions for LISA

The LISA mission is the future space-based gravitational wave (GW)observatory of the European Space Agency. It is formed by 3 spacecraftexchanging laser beams in order to form multiple real and virtualinterferometers. The data streams to be used in order to extract the largenumber and variety of GW sources are Time-Delay Interferometry (TDI) data. Oneimportant processing to produce these data is the TDI on-ground processingwhich recombines multiple interferometric on-board measurements to removecertain noise sources from the data such as laser frequency noise or spacecraftjitter. The LISA noise budget is therefore expressed at the TDI level in orderto account for the different TDI transfer functions applied for each noisesource and thus estimate their real weight on mission performance. In order toderive a usable form of these transfer functions, a model of the beams, themeasurements, and TDI have been developed, and several approximation have beenmade. A methodology for such a derivation has been established, as well asverification procedures. It results in a set of transfer functions, which arenow used by the LISA project, in particular in its performance model. Usingthese transfer functions, realistic noise curves for various instrumentalconfigurations are provided to data analysis algorithms and used for instrumentdesign.<br

A highly stable atomic vector magnetometer based on free spin precession

We present a magnetometer based on optically pumped Cs atoms that measures the magnitude and direction of a 1 $\mu$T magnetic field. Multiple circularly polarized laser beams were used to probe the free spin precession of the Cs atoms. The design was optimized for long-time stability and achieves a scalar resolution better than 300 fT for integration times ranging from 80 ms to 1000 s. The best scalar resolution of less than 80 fT was reached with integration times of 1.6 to 6 s. We were able to measure the magnetic field direction with a resolution better than 10 $\mu$rad for integration times from 10 s up to 2000 s

An Improved Search for the Neutron Electric Dipole Moment

A permanent electric dipole moment of fundamental spin-1/2 particles violates both parity (P) and time re- versal (T) symmetry, and hence, also charge-parity (CP) symmetry since there is no sign of CPT-violation. The search for a neutron electric dipole moment (nEDM) probes CP violation within and beyond the Stan- dard Model. The experiment, set up at the Paul Scherrer Institute (PSI), an improved, upgraded version of the apparatus which provided the current best experimental limit, dn < 2.9E-26 ecm (90% C.L.), by the RAL/Sussex/ILL collaboration: Baker et al., Phys. Rev. Lett. 97, 131801 (2006). In the next two years we aim to improve the sensitivity of the apparatus to sigma(dn) = 2.6E-27 ecm corresponding to an upper limit of dn < 5E-27 ecm (95% C.L.), in case for a null result. In parallel the collaboration works on the design of a new apparatus to further increase the sensitivity to sigma(dn) = 2.6E-28 ecm.Comment: APS Division for particles and fields, Conference Proceedings, Two figure

Dimethylthiourea protects against chlorine induced changes in airway function in a murine model of irritant induced asthma

<p>Abstract</p> <p>Background</p> <p>Exposure to chlorine (Cl₂) causes airway injury, characterized by oxidative damage, an influx of inflammatory cells and airway hyperresponsiveness. We hypothesized that Cl₂-induced airway injury may be attenuated by antioxidant treatment, even after the initial injury.</p> <p>Methods</p> <p>Balb/C mice were exposed to Cl₂gas (100 ppm) for 5 mins, an exposure that was established to alter airway function with minimal histological disruption of the epithelium. Twenty-four hours after exposure to Cl₂, airway responsiveness to aerosolized methacholine (MCh) was measured. Bronchoalveolar lavage (BAL) was performed to determine inflammatory cell profiles, total protein, and glutathione levels. Dimethylthiourea (DMTU;100 mg/kg) was administered one hour before or one hour following Cl₂exposure.</p> <p>Results</p> <p>Mice exposed to Cl₂had airway hyperresponsiveness to MCh compared to control animals pre-treated and post-treated with DMTU. Total cell counts in BAL fluid were elevated by Cl₂exposure and were not affected by DMTU treatment. However, DMTU-treated mice had lower protein levels in the BAL than the Cl₂-only treated animals. 4-Hydroxynonenal analysis showed that DMTU given pre- or post-Cl₂prevented lipid peroxidation in the lung. Following Cl₂exposure glutathione (GSH) was elevated immediately following exposure both in BAL cells and in fluid and this change was prevented by DMTU. GSSG was depleted in Cl₂exposed mice at later time points. However, the GSH/GSSG ratio remained high in chlorine exposed mice, an effect attenuated by DMTU.</p> <p>Conclusion</p> <p>Our data show that the anti-oxidant DMTU is effective in attenuating Cl₂induced increase in airway responsiveness, inflammation and biomarkers of oxidative stress.</p

Characterizing the gamma-ray long-term variability of PKS 2155-304 with H.E.S.S. and Fermi-LAT

Studying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155-304 is analyzed in the high (HE, 100 MeV 200 GeV) gamma-ray domain. Over the course of ~9 yr of H.E.S.S observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index {\ss}_VHE = 1.10 +0.10 -0.13) on time scales larger than one day. An analysis of 5.5 yr of HE Fermi LAT data gives consistent results ({\ss}_HE = 1.20 +0.21 -0.23, on time scales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior ({\ss} ~ 2) seen on shorter time scales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection.Comment: 11 pages, 16 figure

Detailed spectral and morphological analysis of the shell type SNR RCW 86

Aims: We aim for an understanding of the morphological and spectral properties of the supernova remnant RCW~86 and for insights into the production mechanism leading to the RCW~86 very high-energy gamma-ray emission. Methods: We analyzed High Energy Spectroscopic System data that had increased sensitivity compared to the observations presented in the RCW~86 H.E.S.S. discovery publication. Studies of the morphological correlation between the 0.5-1~keV X-ray band, the 2-5~keV X-ray band, radio, and gamma-ray emissions have been performed as well as broadband modeling of the spectral energy distribution with two different emission models. Results:We present the first conclusive evidence that the TeV gamma-ray emission region is shell-like based on our morphological studies. The comparison with 2-5~keV X-ray data reveals a correlation with the 0.4-50~TeV gamma-ray emission.The spectrum of RCW~86 is best described by a power law with an exponential cutoff at $E_{cut}=(3.5\pm 1.2_{stat})$ TeV and a spectral index of $\Gamma$~$1.6\pm 0.2$. A static leptonic one-zone model adequately describes the measured spectral energy distribution of RCW~86, with the resultant total kinetic energy of the electrons above 1 GeV being equivalent to $\sim$0.1\% of the initial kinetic energy of a Type I a supernova explosion. When using a hadronic model, a magnetic field of $B$~100$\mu$G is needed to represent the measured data. Although this is comparable to formerly published estimates, a standard E$^{-2}$ spectrum for the proton distribution cannot describe the gamma-ray data. Instead, a spectral index of $\Gamma_p$~1.7 would be required, which implies that ~$7\times 10^{49}/n_{cm^{-3}}$erg has been transferred into high-energy protons with the effective density $n_{cm^{-3}}=n/ 1$ cm^-3. This is about 10\% of the kinetic energy of a typical Type Ia supernova under the assumption of a density of 1~cm^-3.Comment: accepted for publication by A&

Associations of airway inflammation and responsiveness markers in non asthmatic subjects at start of apprenticeship

<p>Abstract</p> <p>Background</p> <p>Bronchial Hyperresponsiveness (BHR) is considered a hallmark of asthma. Other methods are helpful in epidemiological respiratory health studies including Fractional Exhaled Nitric Oxide (FENO) and Eosinophils Percentage (EP) in nasal lavage fluid measuring markers for airway inflammation along with the Forced Oscillatory Technique measuring Airway resistance (AR). Can their outcomes discriminate profiles of respiratory health in healthy subjects starting apprenticeship in occupations with a risk of asthma?</p> <p>Methods</p> <p>Rhinoconjunctivitis, asthma-like symptoms, FEV1 and AR post-Methacholine Bronchial Challenge (MBC) test results, FENO measurements and EP were all investigated in apprentice bakers, pastry-makers and hairdressers not suffering from asthma. Multiple Correspondence Analysis (MCA) was simultaneously conducted in relation to these groups and this generated a synthetic partition (EI). Associations between groups of subjects based on BHR and EI respectively, as well as risk factors, symptoms and investigations were also assessed.</p> <p>Results</p> <p>Among the 441 apprentice subjects, 45 (10%) declared rhinoconjunctivitis-like symptoms, 18 (4%) declared asthma-like symptoms and 26 (6%) suffered from BHR. The mean increase in AR post-MBC test was 21% (sd = 20.8%). The median of FENO values was 12.6 ppb (2.6-132 range). Twenty-six subjects (6.7%) had EP exceeding 14%. BHR was associated with atopy (p < 0.01) and highest FENO values (p = 0.09). EI identified 39 subjects with eosinophilic inflammation (highest values of FENO and eosinophils), which was associated with BHR and atopy.</p> <p>Conclusions</p> <p>Are any of the identified markers predictive of increased inflammatory responsiveness or of development of symptoms caused by occupational exposures? Analysis of population follow-up will attempt to answer this question.</p