Sample Transfer System Research Articles

In Situ Real-Time Monitoring for Aseptic Drilling: Lessons Learned from the Atacama Rover Astrobiology Drilling Studies Contamination Control Strategy and Implementation and Application to the Icebreaker Mars Life Detection Mission.

In 2019, the Atacama Rover Astrobiology Drilling Studies (ARADS) project field-tested an autonomous rover-mounted robotic drill prototype for a 6-Sol life detection mission to Mars (Icebreaker). ARADS drilled Mars-like materials in the Atacama Desert (Chile), one of the most life-diminished regions on Earth, where mitigating contamination transfer into life-detection instruments becomes critical. Our Contamination Control Strategy and Implementation (CCSI) for the Sample Handling and Transfer System (SHTS) hardware (drill, scoop and funnels) included out-of-simulation protocol testing (out-of-sim) for hardware decontamination and verification during the 6-Sol simulation (in-sim). The most effective five-step decontamination combined safer-to-use sterilants (3%_hydrogen-peroxide-activated 5%_sodium-hypochlorite), and in situ real-time verification by adenosine triphosphate (ATP) and Signs of Life Detector (SOLID) Fluorescence Immunoassay for characterization hardware bioburden and airborne contaminants. The 20- to 40-min protocol enabled a 4-log bioburden reduction down to <0.1 fmoles ATP detection limit (funnels and drill) to 0.2-0.7 fmoles (scoop) of total ATP. The (post-cleaning) hardware background was 0.3 to 1-2 attomoles ATP/cm2 (cleanliness benchmark background values) equivalent to ca. 1-10 colony forming unit (CFU)/cm2. Further, 60-100% of the in-sim hardware background was ≤3-4 bacterial cells/cm2, the threshold limit for Class <7 aseptic operations. Across the six Sols, the flux of airborne contaminants to the drill sites was ∼5 and ∼22 amoles ATP/(cm2·day), accounting for an unexpectedly high Fluorescence Intensity (FI) signal (FI: ∼6000) against aquatic cyanobacteria, but negligible anthropogenic contribution. The SOLID immunoassay also detected microorganisms from multiple habitats across the Atacama Desert (anoxic, alkaline/acidic microenvironments in halite fields, playas, and alluvial fans) in both airborne and post-cleaning hardware background. Finally, the hardware ATP background was 40-250 times lower than the ATP in cores. Similarly, the FI peaks (FImax) against the microbial taxa and molecular biomarkers detected in the post-cleaned hardware (FI: ∼1500-1600) were 5-10 times lower than biomarkers in drilled sediments, excluding significant interference with putative biomarker found in cores. Similar protocols enable the acquisition of contamination-free materials for ultra-sensitive instruments analysis and the integrity of scientific results. Their application can augment our scientific knowledge of the distribution of cryptic life on Mars-like grounds and support life-detection robotic and human-operated missions to Mars.

A fast and robust surface sample acquisition system for a Venus lander

JPL and Honeybee Robotics have designed, built and successfully tested a fast end-to-end sample acquisition and transfer system for the Venusian surface. This full scale prototype system uses a rotary-percussive drill designed to penetrate to a 5 ​cm depth in saddleback basalt in 15 ​min under full Venus surface conditions of 470 ​°C and 92 ​bar pressure and supercritical CO2 atmosphere. The drill features a hollow bit that collects particulate samples created during the drilling process. Sample transfer from drill to lander is done pneumatically using the motive force provided by the high pressure Venus atmosphere to entrain the particles in a high density flow. A cyclone particle separator removes the particles from the flow inside the lander and deposits them into an airlock, while the gas itself flows into a low pressure dump tank. Two samples are provided from the drill, one near the surface and one at 5 ​cm depth. Cross contamination between the near surface and at depth samples is minimized by collecting, but not analyzing, a third sample in between the two primary samples. The airlock is designed to depressurize and cool the particulate samples and then present them to science instruments for composition analysis. The entire drilling and sample transfer process completes in 30 ​min, thereby allowing it to support almost any kind of future short duration Venus lander mission. Results are presented for the first end-to-end drilling and sample transfer experiment conducted in a new specialized test chamber that replicates Venus surface conditions.

Coupled Broad Ion Beam–Scanning Electron Microscopy (BIB–SEM) for polishing and three dimensional (3D) serial section tomography (SST)

Here we describe the first automated fully integrated in-microscope broad ion beam (BIB) system. Ar+-BIB has several advantages over Ga+ focused ion beam (FIB) and Xe+ plasma-FIB (PFIB) methods inducing less beam damage, especially for ion beam sensitive materials. It can mill areas several orders of magnitude larger (up to millimetre scale), and is not confined to the edge of the sample with associated curtaining issues. BIB is shown to have sputter rates up to five times higher than comparable FIB techniques. This new coupled BIB–SEM system (commercial name ‘iPrep™II’) enables in-microscope surface polishing to remove contaminants or damage for two dimensional (2D) imaging, as well as automated serial section tomography (SST) by milling and imaging hundreds of slices, cost and time efficiently. The milled slice thickness can be controlled from a few nanometers up to a micrometre. A novel sample transfer, handling and interlock system allows automated and sequential BIB polishing, scanning electron microscopy (SEM) and analysis by secondary electron (SE) imaging, electron back scatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) for 3D microstructure analysis. Furthermore, insulating surfaces can be sputter coated after milling each slice to reduce charging during SEM analysis. The performance of the instrument is demonstrated through a series of case studies across the materials, earth and life sciences exploiting the imaging, crystallographic and chemical mapping capabilities. These include the study of butterfly defects in bearing steels, meta-stable intermetallic phases in bronze bearings, shale gas rock, aluminium plasma electrolytic oxide (PEO) coatings as well as liver and mouse brain tissues.

Design and construction of a linear motion drive and sample transfer system

Our article focuses on a novel mechanism designed for a linear motion drive, suitable for 250 mm of travel length and compatible with ultrahigh vacuum. As a case study, this mechanism is employed for constructing a simple sample transfer system that allows to store and transfer the samples under high vacuum condition without active pumping system. In our design, we use a typical nut-and-bolt concept to transform the axial rotation motion of a rotary feedthrough attached at one end of the long M6 threaded rod (counterpart of bolt) into linear displacement of a greatly simplified disk (counterpart of nut) that carries samples. Our design is extremely simple, compact, highly versatile, cost effective, and can be readily implemented with an off-centered DN40−16CF reducer and standard DN40CF pipe fittings. Our linear motion drive design can be implemented for various applications such as a sample manipulator, sample storage rack, shielding shutter, or a pillar for pole-stick cleaver.

Molecular beam/infrared reflection-absorption spectroscopy apparatus for probing heterogeneously catalyzed reactions on functionalized and nanostructured model surfaces.

A new custom-designed ultrahigh vacuum (UHV) apparatus combining molecular beam techniques and in situ surface spectroscopy for reactivity measurements on complex nanostructured model surfaces is described. It has been specifically designed to study the mechanisms, kinetics, and dynamics of heterogeneously catalyzed reactions over well-defined model catalysts consisting of metal nanoparticles supported on thin oxide films epitaxially grown on metal single crystals. The reactivity studies can be performed in a broad pressure range starting from UHV up to the ambient pressure conditions. The UHV system includes (i) a preparation chamber providing the experimental techniques required for the preparation and structural characterization of single-crystal based model catalysts such as oxide supported metal particles or ordered oxide surfaces and (ii) the reaction chamber containing three molecular beams-two effusive and one supersonic, which are crossed at the same point on the sample surface, infrared reflection-absorption spectroscopy for the detection of surface-adsorbed species, and quadrupole mass spectrometry for gas phase analysis. The supersonic beam is generated in a pulsed supersonic expansion and can be modulated via a variable duty-cycle chopper. The effusive beams are produced by newly developed compact differentially pumped sources based on multichannel glass capillary arrays. Both effusive sources can be modulated by a vacuum-motor driven chopper and are capable of providing high flux and high purity beams. The apparatus contains an ambient pressure cell, which is connected to the preparation chamber via an in situ sample transfer system and provides an experimental possibility to study the reactivity of well-defined nanostructured model catalysts in a broad range of pressure conditions-up to ambient pressure-with the gas phase analysis based on gas chromatography. Additionally, a dedicated deposition chamber is connected to the preparation chamber, which is employed for the in situ functionalization of model surfaces with large organic molecules serving as promoters or modifiers of chemical reactions. We present a general overview of the apparatus as well as a description of the individual components and their interplay. The results of the test measurements involving the most important components are presented and discussed.

Neutron activation analysis capabilities and applications at the Penn State Radiation Science and Engineering Center

The Penn State Breazeale Reactor has a long history of neutron activation analysis research and development, including applications for forensic applications. Our current experimental capabilities, including a 1 MW TRIGA reactor with a movable core and multiple irradiation locations, a pneumatic sample transfer system, multiple HPGe detectors, and a Compton suppression system, have enabled the development of an active NAA program investigating trace-element concentrations in environmental samples, archaeological samples, and industrial materials. Three NAA projects concerning tree-ring trace element analysis for correlation with large volcanic eruptions, ancient Italian tile element analysis to investigate Roman-era construction materials, and the implementation of k0-standardization method, are highlighted to demonstrate how our facilities and our current NAA research experience make the Penn State RSEC readily available for high-precision trace element analysis for forensics applications.

Note: A simple sample transfer alignment for ultra-high vacuum systems

The alignment of ultra-high-vacuum sample transfer systems can be problematic when there is no direct line of sight to assist the user. We present the design of a simple and cheap system which greatly simplifies the alignment of sample transfer devices. Our method is based on the adaptation of a commercial digital camera which provides live views from within the vacuum chamber. The images of the camera are further processed using an image recognition and processing code which determines any misalignments and reports them to the user. Installation has proven to be extremely useful in order to align the sample with respect to the transfer mechanism. Furthermore, the alignment software can be easily adapted for other systems.

Tip Enhanced Laser Ablation Sample Transfer for Mass Spectrometry

ABSTRACTMass spectrometry is one of the primary analysis techniques for biological analysis but there are technological barriers in sampling scale that must be overcome for it to be used to its full potential on the size scale of single cells. Current mass spectrometry imaging methods are limited in spatial resolution when analyzing large biomolecules. The goal of this project is to use atomic force microscope (AFM) tip enhanced laser ablation to remove material from cells and tissue and capture it for subsequent mass spectrometry analysis. The laser ablation sample transfer system uses an AFM stage to hold the metal-coated tip at a distance of approximately 10 nm from a sample surface. The metal tip acts as an antenna for the electromagnetic radiation and enables the ablation of the sample with a spot size much smaller than a laser focused with a conventional lens system. A pulsed nanosecond UV or visible wavelength laser is focused onto the gold-coated silicon tip at an angle nearly parallel with the surface, which results in the removal of material from a spot between 500 nm and 1 µm in diameter and 200 and 500 nm deep. This corresponds to a few picograms of ablated material, which can be captured on a metal surface for MALDI analysis. We have used this approach to transfer small peptides and proteins from a thin film for analysis by mass spectrometry as a first step toward high spatial resolution imaging.

Characterization of neutron flux spectra in the irradiation sites of a 37 GBq 241Am-Be isotopic source

For the applicability of instrumental neutron activation analysis (NAA) technique, an irradiation unit with a 37GBq 241Am-Be neutron source was installed at Institute of Nuclear Sciences of Ankara University. Design and configuration properties of the irradiation unit are described. It has two different sample irradiation positions, one is called site #1 having a pneumatic sample transfer system and the other is site #2 having a location for manual use. In order to characterize neutron flux spectra in the irradiation sites, the measurement results were obtained for thermal (Фth) and epithermal neutron fluxes (Фepi), thermal to epithermal flux ratio (f) and epithermal spectrum shaping factors (α) by employing cadmium ratios of gold (Au) and molybdenum (Mo) monitors. The activities produced in these foils were measured by using a p-type, 44.8% relative efficiency HPGe well detector. For the measured γ-rays, self-absorption and true coincidence summing effects were taken into account. Additionally, thermal neutron self-shielding and resonance neutron self-shielding effects were taken into account in the measured results. For characterization of site #1, the required parameters were found to be Фth=(2.11±0.05)×103ncm−2s−1, Фepi=(3.32±0.17)×101ncm−2s−1, f=63.6±1.5, α=0.045±0.009, respectively. Similarly, those parameters were measured in site #2 as Фth=(1.49±0.04)×103ncm−2s−1, Фepi=(2.93±0.15)×101ncm−2s−1, f=50.9±1.3 and α=0.038±0.008. The results for f-values indicate that good thermalization of fast neutrons on the order of 98% was achieved in both sample irradiation sites. This is because an optimum combination of water and paraffin moderator is used in the present configuration. In addition, the shielding requirements are met by using natural boron oxide powder (5.5cm) and boron loaded paraffin layers against neutrons, and a 15cm thick lead bricks against gamma-rays from source and its surrounding materials.

Invited: Electrochemical Properties for UHV-Prepared Pt/M Well-Defined Single Crystal Surfaces

Background Discussion on oxygen reduction reaction (ORR) mechanisms1) of alloy catalysts is complicated because of uncertainties in outermost surface structures. To clarify the effect of catalyst’s outermost surface structures on ORR, Markovic and co-workers2) evaluated ORR activities single-crystal planes of Pt3Ni. Their pioneering work clearly demonstrates that design of atomic arrangements of the catalyst surfaces directly links to developments in superior PEFC cathode electrode catalysts. To date, EC properties for the Pt-based single crystal alloy surfaces have been reported3-9): our approach is well-defined model-catalyst fabrications by using molecular beam epitaxy in ultra-high vacuum (UHV:~10-8Pa) condition. In this study, ORR activities and structural stabilities for the UHV-prepared well-defined Pt-based bimetallic (Pt/M) surfaces are discussed. Experimental The MBE apparatus and UHV-EC sample transfer system have been described earlier10). Pt-shell layers were prepared on fcc single crystal substrates through electron-beam vacuum depositions of another elements and thermal annealing in UHV. The resulting surface structures were verified with reflection high-energy electron diffraction (RHEED), IR reflection absorption (IRRAS) spectra for carbon monoxide (CO) adsorption, and scanning tunneling microsope (STM). The UHV-prepared samples were transferred to a N2-purged glove box without air exposure. CV curves are recorded in N2-purged 0.1 M HClO4. After that, LSV measurements were conducted in O2-saturated 0.1 M HClO4: RHE is used as a reference electrode. Results and discussion Pt/Au(111): On the basis of RHEED and CO-IRRAS measurements, epitaxial growth of Pt on Au(111) was confirmed. On the basis of the hydrogen-adsorption charges (QHad), we deduce that the 0.3nm-thick Pt almost covers the Au(111) substrate. The half-wave potential for the Pt0.3nm/Au(111) was ca. 10mV more positive than that of the Pt(111). In contrast, the potential for the Pt0.15nm/Au(111) shifted 60mV negatively. The results show that extended Pt(111) domains might correlate with the ORR activity enhancement. Ni/Pt(111)-skin: A UHV-STM image of the sample fabricated through 1ML-thick Ni deposition on ca. 800K-Pt(111) (Ni/Pt(111)-skin) showed 6-fold symmetric, honeycomb atomic arrangement. However, atomic-scale disorder with a corrugation of 0.06-0.12nm height is present at the topmost surface. XPS analysis showed positive shift of Pt 4f band. The LSV curve of the Ni/Pt(111)-skin shifted 70mV positively, suggesting that remarkable ORR activity enhancement is originated from the strains- and electronic-changes of the topmost Pt(111) lattice. Pt/Pd(111): Atomically flat PtmML/Pd(111) surfaces were prepared through Pt depositions on Pd(111) at 673 K. The LSV curve for the Pt2ML/Pd(111) showed 20mV positive shift relative to clean Pt(111). To evaluate EC stability of the PtmML/Pd(111), potential cycles (0.6~1.0V) were applied in O2 saturated 0.1M HClO4. Although the Pt layers less than 2MLs showed decrease in activity with increasing cycles, the activity of the Pt4ML/Pd(111) remained nearly unchanged during the cycles. EC Stability: Changes in ORR activities for the Pt-shell layers (Pt/Au(111), Ni/Pt(111)-skin, Pt/Pd(111)) during the potential cycles are summarized in Fig. 1. The results suggest that the Pt-shell layers thicker than 3MLs stabilize the topmost Pt(111) lattice in PEFC conditions. Acknowledgement This work was supported by NEDO. References 1)T.Toda et al. JES, 146, 3750 (1999).2)V.R.Stamenkovic et al. Science 315, 493 (2007).3)H. E. Hoster et al. Chemphyschem. 11, 1518 (2010).4)J.Baricuatro and M. Soriaga, Electrocatal. 1, 42, (2010).5)A.Bergbreiter et al. Chemphyschem. 11, 1505 (2010).6)S.Axnanda, et al. Chemphyschem. 11, 1468 (2010).7)M.Wakisaka, et al. Electrochem.Commun. 13, 317 (2011).8)I. E. L. Stephens et al. JACS 133, 5485 (2011).9)T.Rurigaki et al. JEAC, 716, 58 (2014).10)T.Wadayama et al. Electrochem.Commun. 12, 1112(2010). T.Wadayama et al. JPCC 115, 18589 (2011). Y.Iijima. et al., JEAC, 685, 79 (2012). Y.Yamada et al. Surf. Sci. 607, 54 (2013). N.Todoroki et al., PCCP, 15, 17771 (2013).

ORR Activity for Pt/Pd(111) Bimetallic Surface Prepared By Molecular Beam Epitaxy

Background From the view-points of reduction in usage of expensive Pt and enhancement in oxygen reduction reaction (ORR) activity [1], Pt-shell and Pd-core, core-shell type nano-particles attract much interest as cathode-electrode materials for polymer electrolyte fuel cells. Relation between topmost surface structures of the core-shell nano-particles and ORR activities is a key for developing highly-active, low-Pt-content catalysts. However, disscussion of ORR mechanism is complicated. In this study, we prepared well-defined Pt/Pd(111) bimetallic surfaces by molecular beam epitaxy (MBE) in ultra-high vacuum (UHV) and performed EC measurements in an inert gas atomosphere. Experimental The MBE apparatus and UHV-EC sample transfer system have been described earlier [2]. All sample fabrication processes were conducted in UHV. Pd(111) single crystal substrate was cleaned by Ar+ sputtering and annealing. Various-thick Pt was deposited onto the clean Pd(111) by an electron-beam evaporation method at 673K. The resulting surface structures were verified with low energy electron diffraction (LEED), scanning tunelling microscope in UHV (UHV-STM). Then, the MBE-prepared Ptxnm/Pd(111) surfaces were transferred without being exposed to air to the EC system set in an N2-purged glove box. Cyclic voltammogram (CV) of the samples were recorded in N2-purged 0.1M HClO4, and, then, linear sweep voltammetry (LSV) was conducted by a rotating electrode (RDE) method at 1600 rpm after saturating the solution with O2. EC degradation of the Ptxnm/Pd(111) was evaluated by applying potential cycles between 0.6V (3s) and 1.0V (3s) vs. RHE. The potential-cycled Ptxnm/Pd(111) were re-transferred to the UHV-STM system to evaluate the potential-cycle-induced topmost surface structural changes. Results and discussion From the results obtained by LEED and IRRAS for carbon monoxide adsorption, we deduce that 0.6nm-thick Pt almost covers the Pd(111) substrate surface. A UHV-STM image of the Pt0.6nm/Pd(111) (inset in Fig. 1 (a)) clearly shows atomically-flat, wide terraces. Fig. 1 (a) shows CV curves of the Pt0.6nm/Pd(111) (blue). CV curves for clean Pt(111) (black) and Pd(111) (grey) are also presented as references. EC charge of the H-related features (0.15V-0.3V ; Qab&de) for the Pt0.6nm/Pd(111) markedly shirinks in comparison to that of clean Pd(111), suggesting that the topmost surface of the Pt0.6nm/Pd(111) is epitaxial Pt(111). Fig. 1 (b) shows LSV curves for the respective surfaces. A half-wave potential of the as-prepared Pt0.6nm/Pd(111) (blue) shifts positively relative to clean Pt(111), indicating ORR activity enhancement. The LSV curve of the as-prepared Pt0.6nm/Pd(111) shifts to lower potentials after the 1000 potential cycles (red), revealing potential-cycle induced surface degradation. One might notice that the red LSV curve is almost identical to that for 0.15nm-thick-Pd deposited Pt(111) (Pd0.15nm/Pt(111);green). The results obtained in this study suggest that the topmost surface of MBE-prepared Pt0.6nm/Pd(111) is degraded through dissolution and precipitation of the substrate Pd atoms during the potential cycles. Acknowledgement This work was supported by New Energy and Industrial Technology Development Organization (NEDO).

Development of a fast-pneumatic sample transfer system for DT neutron activation analysis at the University of Michigan

The development of an automated pneumatic transfer system used to quickly acquire data from materials irradiated with a deuterium–tritium (DT) neutron generator is described in this paper. This system was designed to gather data on short-lived activation and fast-fission products, and was used to characterize the generator’s neutron field. The average sample transit time between irradiation and data acquisition is 363.9 ms at an average velocity of 30.92 m/s (101.3 ft/s). The neutron flux profile as a function of depth into the sample capsule is shown to decrease exponentially, having a maximum flux value of 5.662 × 108 ± 0.056 × 108n/cm2 s. The average DT neutron energy in the system’s sample geometry was determined to be 14.250 ± 0.011 MeV using a unique zirconium–niobium “sandwich” technique. A flux surface equation is also presented as a function of accelerator voltage and deuterium beam current. Methods of analysis are discussed with a proof of a linear flux profile assumption for thin foils.

High‐resolution40Ar/39Ar dating using a mechanical sample transfer system combined with a high‐temperature cell for step heating experiments and a multicollector ARGUS noble gas mass spectrometer

Abstract40Ar/39Ar dating of young (&lt;1 Ma) and/or low potassium samples requires degassing of large amounts of material either by a laser or a furnace. A furnace excels in precise and reproducible temperature control and in providing a homogeneous temperature distribution even for relatively large sample amounts. For most systems, however, the degassed mineral or whole‐rock residues remain in the crucible after measurement. This reduces the thermal conductivity and increases the blank levels and baking times. To mitigate these problems, we combined a mechanical sample transfer system with a low volume (∼90 mL) high‐temperature cell. The system operates under ultrahigh vacuum and uses Mo‐crucibles, in which up to 1000 mg of sample is transferred into the furnace and taken out after degassing. The system has short baking times (20–30 min), highly reproducible heating conditions and an overall low blank level due to the absence of silicate (glassy) sample residue in the main crucible of the furnace. The system interconnects through a gas purification line with a low volume, high sensitivity multicollector ARGUS noble gas mass spectrometer. Intraday reproducibility of40Ar/36Ar ratios measured on air aliquots of &gt;5 × 10−16mol36Ar is better than 0.5‰–1.0‰ (1σ,n = 4–8). We illustrate the system performance by40Ar/39Ar dating of whole‐rock samples and mineral separates from the Oman ophiolite as well as from the Siebengebirge, Heldburg, and Rhön volcanic provinces in Central Germany.

Deuterium release from lithium–deuterium films, deposited in the magnetron discharge

A set-up for co-deposition of lithium–deuterium mixed films and in situ thermal desorption spectroscopy is described. The set-up consists of a HV chamber with a magnetron discharge for Li–D co-deposition, UHV chamber for thermal desorption measurements and a sample transfer system between the chambers. It was found that a large amount of deuterium was accumulated in the lithium films. Deuterium thermal desorption spectra had two sharp peaks with maxima around 710 K and 850 K. Li–D films kept in air at room temperature lost deuterium; no deuterium was detected in the films after three days in air.

An automatic microfluidic sample transfer and introduction system

We report an easily setup, reliable and automatic microfluidic sample transfer and introduction system. Two different function liquid detection modules were developed to separately perform rapidly removing of a large approximate volume of air off chip and a low-speed high precision small volume of air purging process on chip incorporating liquid-on-chip handling module. As a proof of concept, we demonstrated that a small volume of radioactive sample as low as 5 μL could be successfully transferred and introduced from vials to the desired location in the microfluidic chip with minimal loss (2.1 ± 0.4 %, n = 3). The total time of the sample transfer and introduction was less than 1 min. The complete automation would facilitate the safe handling of the dangerous and toxic materials, such as radioactive compound.

Development of Automatic Sample Exchange and Transfer System in iMATERIA

Development of Automatic Sample Exchange and Transfer System in iMATERIA

Confocal sample-scanning microscope for single-molecule spectroscopy and microscopy with fast sample exchange at cryogenic temperatures

The construction of a microscope with fast sample transfer system for single-molecule spectroscopy and microscopy at low temperatures using 2D/3D sample-scanning is reported. The presented construction enables the insertion of a sample from the outside (room temperature) into the cooled (4.2 K) cryostat within seconds. We describe the mechanical and optical design and present data from individual Photosystem I complexes. With the described setup numerous samples can be investigated within one cooling cycle. It opens the possibility to investigate biological samples (i) without artifacts introduced by prolonged cooling procedures and (ii) samples that require preparation steps like plunge-freezing or specific illumination procedures prior to the insertion into the cryostat.

Development of a XAFS Measurement System in the Soft X-ray Region for Various Sample Conditions

We developed a XAFS measurement system applicable for various sample conditions at the soft X-ray double crystal monochromator beamline (BL-10) of the SR center, Ritsumeikan University. The measurement system consists of two directly connected chambers; one in high vacuum with a newly-developed sample transfer system and another in 1 atm He. A sample decomposed by evacuation can be measured in 1 atm He gas chamber, while a sample unstable in air can be prepared in a glove box, transferred with a transfer vessel and installed in a high vacuum chamber without exposing to air. This system opens a new applicability of XAFS measurements in the soft X-ray region.

Production of highly charged ions in the range of energy of 10 V × q up to MeV

A new ion irradiation facility for the formation of beams of highly charged ions in a wide range of kinetic energy from about 10V×q up to MeV is presented. The ions are produced in sources of the Dresden EBIT type which allow the production of a wide spectrum of highly charged ions such as C6+, Ar18+, Ni28+, Kr35+ and Xe44+, respectively. The integral ion output of these ion sources is in the order of some μA per pulse at pulse widths of 2μs up to about 10μs. For individual ion charge states ion currents of up to about 100 nA per pulse can be obtained. In DC extraction mode (leaky mode) ion currents in the order of hundreds of pA are detected. An advanced Dresden EBIT type source, the Dresden EBIS-A, is employed at an irradiation facility. The target chamber comprises a sample manipulation and transfer system as well as numerous preparation and diagnostic tools. The facility will provide an experimental environment for basic research in atomic and solid state physics as well as for applied technology in areas such as surface engineering, surface analysis, nanostructuring and nanobiotechnology.

Synthesis of nanocrystalline MgH 2 powder by gas-phase condensation and in situ hydridation: TEM, XPS and XRD study

In this work, a two-step method for the preparation of nanocrystalline MgH 2 is presented, where the first step consists of synthesis of nanocrystalline Mg powder by the gas-phase condensation method (GPC) and the second of in situ hydridation leading to the formation of MgH 2 nanoparticles. By transmission electron microscopy (TEM) and electron diffraction (ED), crystalline Mg nanoparticles from GPC were found to have mean size within the range of 30–50 nm, while in the case of MgH 2 nanoparticles these values increase approximately 2–3 times mainly due to particles growth during the hydridation step. The X-ray diffraction (XRD) analysis shows the high conversion into the MgH 2 phase after hydridation. By X-ray photoelectron spectroscopy (XPS) metallic magnesium was detected below a magnesium oxide layer of 3–4 nm for the Mg sample prepared by GPC, which shows the efficiency of a novel sample transfer system without air exposure between N 2-glove-box, preparation chamber and experimental apparatus.