Torsten Henkel

The University of Manchester · School of Earth, Atmospheric and Environmental Sciences

We report an in-situ investigation of silicon nitride (Si3N4) grains from several enstatite chondrites of low petrologic types (EL3, EH3, and EH4). The grains occurred in various host phases, including Fe,Ni metal, schreibersite, sulfides, and also in the silicate fraction, and are of Solar System origin. Energy-dispersive X-ray spectroscopy (EDS)...

We report the light to intermediate-mass element abundances as well as the oxygen, magnesium, silicon, and titanium isotope compositions of a unique and unusually large (0.8 µm × 3.75 µm) presolar O-rich grain from the Krymka LL3.2 chondrite. The O-, Al-, and Ti-isotopic compositions are largely compatible with an origin from an asymptotic giant br...

Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplar...

High abundances of heterogeneously distributed organic material from the production process in the aerogel tiles hamper detection of cometary organic material.

This chapter focuses on time-of-flight secondary ion mass spectrometry (TOF-SIMS), where the ion beam is pulsed, and extensions that involve postionization of sputtered neutrals. It introduces the basic principles of TOF-SIMS and discusses recent applications in inorganic chemistry. Variations of the technique that make it useful for organic analys...

Owing to their incompatibility, halogens have similar geochemical properties to noble gases in many systems and may therefore be used as key tracers of volatile transport processes in the earth. Halogen fractionation may occur during partial melting of the upper mantle, fractional crystallization or partitioning between immiscible fluids. Experimen...

Using time-of-flight secondary ion mass spectrometry to record complete mass spectra enables determination of whole molecules rather than functional groups only.

We have analyzed eleven presolar SiC grains from the Murchison meteorite using time-of-flight secondary ion mass spectrometry. The Si isotopic compositions of the grains indicate that they are probably of an AGB star origin. The average abundances of Mg, Fe, Ca, Al, Ti, and V are strongly influenced by their condensation behavior into SiC in circum...

We studied the survival and chemical processing of organic material in high velocity impacts (~6 km/s) onto Al-foil. This will help to identify organic crater residues which have been found on the Stardust Al-foils.

Organic material was captured on the Al foils of the Stardust collector. We studied the survival of organic material under Stardust conditions to understand the processing that organic crater residues, found on the flight foils, must have undergone.

The sputtering process of presolar grains is simulated to deconvolute TOFSIMS depth profiles. This helps to determine the interior structure, which provides clues about the history of the grains like shockwave implantation of trace elements.

We have located a series of micron-sized amorphous carbonaceous grains in size and density separations of Murchison matrix. We argue that the grains lost their crystalline structure through ion irradiation by the solar wind in the proto-solar nebula.

Every atom counts when analyzing tiny samples. Using femtosecond lasers for post-ionization of sputtered neutrals simplifies and improves elemental quantification and has the potential to boost the efficiency with which the samples are analysed.

The secondary ion mass spectrum of silicon sputtered by high energy C60+ ions in sputter equilibrium is found to be dominated by Si clusters and we report the relative yields of Sim+ (1 ≤ m ≤ 15) and various SimCn+ clusters (1 ≤ m ≤ 11 for n = 1; 1 ≤ m ≤ 6 for n = 2; 1 ≤ m ≤ 4 for n = 3). The yields of Sim+ clusters up to Si7+ are significant (betw...

Precious metals supported on ferrimagnetic particles have a diverse range of uses in catalysis. However, fabrication using synthetic methods results in potentially high environmental and economic costs. Here we show a novel biotechnological route for the synthesis of a heterogeneous catalyst consisting of reactive palladium nanoparticles arrayed on...

We report an unusual regular-sided clast in the matrix of Orgueil (CI1), around 0.75 mm in diameter. We use SEM, EMPA and ToF-SIMS techniques to study this clast, and discuss its potential origins.

We present our first measurements of IOM residues analyzed with time-of-flight secondary ion mass spectrometry utilizing C60+ primary ions.

TOFSIMS has been systematically used to study the distribution of trace elements in seven presolar SiC grains. There is evidence to suggest that some trace elements may have been implanted into the grains.

Abstract— Thirteen presolar silicon carbide grains—three of supernova (SN) origin and ten of asymptotic giant branch (AGB) star origin—were examined with time-of-flight-secondary ion mass spectrometry (TOF-SIMS). The grains had been extracted from two different meteorites—Murchison and Tieschitz—using different acid residue methods. At high lateral...

In recent years, Au-cluster ions have been successfully used for organic analysis in secondary ion mass spectrometry. Cluster ions, such as Au(2)(+) and Au(3)(+), can produce secondary ion yield enhancements of up to a factor of 300 for high mass organic molecules with minimal sample damage. In this study, the potential for using Au(+), Au(2)(+) an...

Time-of-flight secondary ion mass spectrometry is a very useful tool for the comprehensive characterization of samples by in situ measurements. A pulsed primary ion beam is used to sputter secondary ions from the surface of a sample and these are then recorded by a time-of-flight mass spectrometer. The parallel detection of all elements leads to ve...

The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA’s Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explan...

Acfer 094 matrix has been studied by TOFSIMS elemental and isotopic analysis. Unusual minerals including a Li and Cr silicate has been found. These unusual minerals may account for a significant fraction of the budget of lithium and chromium in Acfer 094.

Surfaces of Stardust aerogel have been analyzed with latest technology ToF-SIMS, utilising a beam of 40kV C60 ions, most suitable to measure heavy organic compounds at high lateral resolution.

A gentle separation procedure has been used to isolate presolar graphite grains from the Murchison meteorite. This provides pristine samples with which to study stellar environments. We report the the first TOFSIMS analyses of a gently separated presolar graphite grain.

The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA’s Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explan...

A TOFSIMS method is described for the simultaneous analysis of implanted solar wind atoms into Genesis collectors. Results from diamond are presented indicating probable simultaneous detection of solar wind Mg and Fe.

Surfaces of flight aerogel exposed to the cometary particle flux as well as unexposed have been analyzed with latest technology ToF-SIMS, utilising a beam of 40kV C60 ions, most suitable to measure heavy organic compounds at high lateral resolution.

A new high sensitivity TOFSIMS analysis method is described for the analysis of solar wind implanted elements into Genesis collectors. Application and results from Si collectors are presented.

We present the performance characteristics of a time-of-flight secondary ion mass spectrometer designed for 157 nm laser postionization of sputtered neutrals for high sensitivity elemental and isotopic analyses. The instrument was built with the aim of analyzing rare element abundances in micron to submicron samples such as interstellar grains and...

Abstract— We report the first measurements of lithium and boron isotope ratios and abundances measured in “gently separated” presolar SiC grains. Almost all analyses of presolar SiC grains since their first isolation in 1987 have been obtained from grains that were separated from their host meteorite by harsh acid dissolution. We recently reported...

We are undertaking comprehensive, all-element analyses of presolar SiC grains by high resolution TOFSIMS depth profiling. This abstract looks at some experimental artifacts that limit the resolution and accuracy of data that can be obtained.

TOFSIMS analysis of Genesis samples and standards is described. The techniques are complementary to existing SIMS techniques.

Depth profiles for several elements have been acquired for four presolar SiC grains from the Murchison KJG-fraction. The data corroborates previous results showing implanted interstellar matter in some of these grains.

The Rhodope Massif in N. Greece is a newly established ultrahigh-pressure metamorphic (UHPM) province in the world (Mposkos & Kostopoulos, 2001). Microscopic observations on zircons separated from a garnet gneiss revealed a simple zoned structure consisting of a somewhat rounded detrital core and a metamorphic overgrowth rim. Microdiamonds were ide...

We have constructed a TOFSIMS instrument based upon the BIOTOF design. SIMS mapping of mass resolved secondary ions and molecules with an intrinsic mass resolving power of 3700 has been achieved with an estimated spatial resolution of 250 nm. We have conducted studies of non-resonant laser post-ionization of sputtered neutrals in order to improve t...

Evidence for a coat-core structure of presolar SiC-grains was found in a comprehensive study of acid-free extracted grains. Comparison with acid-residue grains showed alterations these ones have experienced in the extraction process.

We compare two "identical" looking micrometeorites using TOFSIMS and TEM to determine whether glacial and aeolian micrometeorites differ due to their collection methods.

Lithium and Boron isotope and elemental analyses have been acquired from pristine pre-solar silicon carbide grains, separated from the Murchison meteorite by a new acid-free technique. Results indicate acquisition of a rim on the grain from interstellar space.

We have developed a new TOFSIMS/laser-SNMS instrument for the analysis of interstellar grains using laser secondary neutral mass spectrometry to improve sensitivity and quantification over SIMS analysis for the heavier elements of the periodic table.

We present a comparison of elemental abundances, by TOFSIMS analysis, in presolar silicon carbide grains including grains separated by acid dissolution and grains separated by a new gentle separation method to look for artificial anomalies.

This paper describes the development of a new, effective and non-destructive method of SiC isolation from meteorites by freeze -thaw disaggregation, size and density separation. This new method is important because there is evidence that current methods, developed over the last 18 years, using strong acids and chemical treatments to dissolve silica...

Trace element analyses of mineral grains in CI chondrites show strong enrichment of REE in heterogeneously distributed phosphates, while sulfates and matrix material have REE abundances close or below the solar system abundance.

Präsolare Körner mit Größen von wenigen Mikrometern gestatten einen Einblick in das Sterninnere, da sie Kondensate von Sternmaterial sind und die Entstehung des Sonnensystems überlebten. Man extrahiert sie mit Säuren aus primitiven Meteoriten. Mit der Flugzeit-Sekundärionenmassenspektrometrie sind durch die Aufnahme kompletter Massenspektren umfass...

Silicate-rich fragments from CI chondrites were analyzed with electron microprobe and TOF-SIMS to investigate chemical heterogeneities in these meteorites. Considerable variations were found for most major elements, especially for S, K, Na and P.

We present first data on event-by-event fluctuations in the average transverse momentum of charged particles produced in Pb+Pb collisions at the CERN SPS. This measurement provides previously unavailable information allowing sensitive tests of microscopic and thermodynamic collision models and to search for fluctuations expected to occur in the vic...

The NA49 detector is a wide acceptance spectrometer for the study of hadron production in p+p, p+A, and A+A collisions at the CERN SPS. The main components are 4 large-volume TPCs for tracking and particle identification via dE/dx. TOF scintillator arrays complement particle identification. Calorimeters for transverse energy determination and trigg...

The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 A GeV has been measured by the NA49 experiment. The results are compared to model predictions from static thermal Gaussian proton source distributions and transport models rqmd and venus. An effective proton source size is determined by minimizing χ2/ndf between...

The NA49 experiment is able to measure the production of neutral strange baryons and mesons along with other hadronic species in Pb + Pb collisions at 158 GeV per nucleon. These strange particles are an important piece of evidence in the search for the quark-gluon plasma. They have been reconstructed from their charged decay products recorded in th...

Preliminary inclusive spectra for K+, K-, Ks0, Λ, and are presented which were measured in central Pb + Pb collisions at 158 GeV per nucleon by the NA49 experiment. A comparison with data from lighter collision systems shows a strong change of the shape of the Λ rapidity distribution. The strangeness enhancement observed in S + S compared to p + p...

Strangeness measurements in NA49 indicate a strangeness enhancement in Pb + Pb interactions, relative to the elementary nucleon-nucleon and nucleon-nucleus collisions. It appears that the magnitude of the enhancement is similar in Pb + Pb and S + nucleus collisions. The enhancement is present in almost every central Pb + Pb collision, the dynamical...

We report measurements of Ξ− and hyperon absolute yields as a function of rapidity in 158 GeV/c Pb+Pb collisions. At midrapidity, dN/dy=2.29±0.12 for Ξ−, and 0.52±0.05 for , leading to the ratio of . Inverse slope parameters fitted to the measured transverse mass spectra are of the order of T≈300 MeV near mid-rapidity. The estimated total yield of...

Data on φ-production obtained by the CERN NA49 experiment for central Pb+Pb collisions at 158 GeV/u are presented. Compared with pp interactions the φ-yield shows substantial strangeness enhancement: the φ/π ratio is found to increase by a factor of 2.6 ± 0.6, which is approximately the square of the K/π enhancement.

The composition of forward-going projectile spectator matter in fixed-target Pb+Pb collisions at 158 A · GeV at the CERN SPS has been studied as a function of centrality. The data were measured with the NA49 veto calorimeter. We observe that forward-going spectator matter in central collisions consists of 9 neutrons, 7 protons, and half a deuteron...

The directed and elliptic flow of protons and charged pions has been observed from the semi-central collisions of a 158 GeV/nucleon Pb beam with a Pb target. The rapidity and transverse momentum dependence of the flow has been measured. The directed flow of the pions is opposite to that of the protons but both exhibit negative flow at low pt. The e...

In this paper we present recent results from experiment NA49 on single- and multiparticle distributions obtained for Pb+Pb collisions at 158GeV/nucleon at the CERN SPS. NA49 aims at a complete description of the hadronic final state of nuclear collisions, which will eventually allow us to establish whether an equilibrated, deconfined state of parto...

The directed and elliptic flow of protons and charged pions has been observed from the semicentral collisions of a 158GeV/nucleon Pb beam with a Pb target. The rapidity and transverse momentum dependence of the flow has been measured. The directed flow of the pions is opposite to that of the protons but both exhibit negative flow at low p{sub t} ....

Two-particle correlation functions of negative hadrons over wide phase space, and transverse mass spectra of negative hadrons and deuterons near mid-rapidity have been measured in central Pb+Pb collisions at 158 GeV per nucleon by the NA49 experiment at the CERN SPS. A novel Coulomb correction procedure for the negative two-particle correlations is...

Preliminary inclusive spectra for , , , , and are presented which were measured in central Pb+Pb collisions at 158 GeV per nucleon by the NA49 experiment. A comparison with data from lighter collision systems shows a strong change of the shape of the rapidity distribution. The strangeness enhancement observed in S+S compared to p+p and p+A is not f...

Using the NA49 main TPC, the central production of 0954-3899/23/12/005/img5 hyperons has been measured in CERN SPS Pb - Pb collisions at 0954-3899/23/12/005/img6. The preliminary 0954-3899/23/12/005/img7 ratio, studied at 0954-3899/23/12/005/img8 and 0954-3899/23/12/005/img9, equals 0954-3899/23/12/005/img10 (systematic error only). It is compatibl...