Introduction

Greetings from a cold Canberra winter. We look forward to seeing you at Goldschmidt in (hopefully warmer) Prague, at Booth 50 (Foyer 2), to discuss the new SHRIMP IV, review updates to the Alphachron^TM thermochronology instrument and see the GA SHRIMP IIe running geochronology with an ¹⁸oxygen primary beam, a novel technique for enhanced Pb/U calibration.

The New SHRIMP IV

ASI is formally announcing the revolutionary new SHRIMP IV ion probe at the Goldschmidt meeting. SHRIMP IV is the commercial, dual polarity version of the ground-breaking SHRIMP SI (stable isotope) machine developed by the ANU Research School of Earth Sciences. SHRIMP IV features;

• New primary column design with submicron primary beam spots under Kohler illumination, and enhanced rastering;
• Dual sample lock stages with up to 11 samples under vacuum, and lower chamber pressures;
• Optimised secondary column design coupled with enhanced main quadrupole, for higher throughput and even greater ease of tuning;
• Flexible multi-collector design options, tailored to user requirements, coupled with the new iFlex capacitance mode electrometers, allowing Faraday cup measurements down to 50 kHz.

These new features are combined with the established SHRIMP attributes of high sensitivity with high resolution, ease of tuning and stability of operation and reliable and easily maintained electronics, making SHRIMPs the most scientifically productive ion probes available. Visit the ASI team at the booth to learn more about the new SHRIMP IV, and review the poster papers from the ANU. The photograph shows Professor Trevor Ireland and Dr John Foster, with the new SHRIMP.

Goldschmidt 2011

ASI will be at Booth 50, Foyer 2, of the Goldschmidt conference, demonstrating the remote access and automated operation pioneered by the ANU and ASI and for which SHRIMPs are renown As well as attending Goldschmidt as exhibitors, Dr Chuck Magee is presenting a poster on the enhanced uranium-lead calibration possible with an ¹⁸O primary beam. Since the SHRIMP instruments do not require oxygen flooding to achieve their high sensitivity, this is a promising and powerful new approach to SHRIMP geochronology. Chuck Magee is presenting a poster on this work in Session 18c, poster 4006 on Wednesday.

The GA SHRIMP will be demonstrating this innovation, via remote access to the booth. ASI are also sponsoring the detrital zircon workshop ahead of the main meeting (http://www.geo.uib.no/bgf/index.php/detrital-workshop-registration) . Dr Keith Sircombe, head of the Geoscience Australia SHRIMP, is presenting at the workshop. Keith has extensive detrital experience, and is currently working on sediment provenance for the North West Shelf hydrocarbon area.

Discuss the new SHRIMP IV with the team. The plot above shows 4-cup sulfur measurements. Note the separation of the ³²SH shoulder on the green ³³S plot. This instrument already achieves <0.2 ‰ Δ³⁶S (1σ).

Granada SHRIMP IIe/MC

The University of Granada SHRIMP IIe/MC was successfully installed and commissioned in April, meeting its performance requirements in both positive and negative ion modes within the target 6 weeks from uncrating the instrument. Professor Fernando Bea has an extensive program of both geochronology and stable isotope analysis planned for the machine. Time has been set aside for European users to visit to familiarize themselves with the capabilities of this SHRIMP, and anyone interested should contact him; fbea@ugr.es.

GA SHRIMP - 3 Years Old

The Geoscience Australia SHRIMP marked three years since its official opening in April. Up until 14 July the Laboratory Information Management System has logged 43371 analyses over 466 sessions within the 72% of time available to GA. ASI have recently upgraded the machine with a new main quadrupole, which has increased its sensitivity, resolution and ease of tuning. A new 3-axis sample stage with optical encoding and sub-micron steps has been built, along with an extended-length Kohler aperture bar. As well as being a workbench for instrument hardware and software development, and technique refinement (such as the ¹⁸O primary beam) during ASI's 28% timeshare, it has been used for training, and demonstration to several international visitors during the year.

In the GA SHRIMP Laboratory itself, Dr Dan Dunkley has joined after seven years at the Japanese Institute for Polar Research SHRIMP II in Tokyo. Dan will be supporting Geological Survey of Queensland field programs and also brings a wealth of experience to several development projects underway in the Lab.

Departure of Peter Laughlin

ASI was sad to farewell Dr Peter Laughlin, who has left to become Director of the Alliance College of Australia, the denominational college of the Christian and Missionary Alliance of Australia. It’s a big difference to building Alphachrons and documenting SHRIMPs, but we wish him well in this new role, and thank him for his very considerable contributions to ASI during his time with us.

Alphachron^TM Developments

Ongoing developments of ASI’s unique Alphachron^TM, made under licence from the CSIRO, have included redesign of the quartz-halogen diffusion cell used to determine closure temperature and automation of the diffusion cell measurement to allow long term measurements to be made in the background, interspersed with automated foreground laser extraction from 25 samples per sample puck. The line gettering design has been upgraded to further reduce helium blank levels, and the option for laser step-heating of the 25 samples is now available, using an optical pyrometer for accurate sample temperature control.

The Alphachron^TM laser heating subsystem is shown, with the combined camera-pyrometer, infrared fibre-coupled laser with turning mirror, 25-sample vacuum cell and x-y driving stages.The step heating subsystem is available as an upgrade to earlier helium systems, or as a stand-alone product for Argon-Argon systems.

SHRIMP Workshop

The 6th biennial SHRIMP Workshop will be held from 1-4 August 2012 at O’Reilly’s Rainforest Retreat in Lamington National Park near Brisbane, Australia. The workshop immediately precedes the 34th International Geological Congress in Brisbane starting on 5 August 2012. Geoscience Australia is hosting the workshop with sponsorship from ASI.

As attendees of previous workshops will attest, this will be an excellent forum for a detailed discussion of SHRIMP techniques, sharing ideas and renewing contacts. For more information contact shrimp2012@ga.gov.au, visit www.ga.gov.au/minerals/projects/current-projects/geochronology-laboratory/geochronology-workshop or the SHRIMP Fan Club Facebook group www.facebook.com/home.php#!/groups/81699833602?ap=1 , for those that dare …

Upcoming Conferences

ASI will be sponsoring and attending the 6th Biennial Geochemical SIMS Workshop in Hawaii on 3-4  November, 2011. For details, contact Dr Gary Huss, ghuss@higp.hawaii.edu or visit http://www.higp.hawaii.edu/bgsw6.html

ASI will be sponsoring and attending the 14th Indian Society of Mass Spectrometry Conference to be held at Munnar, Kerala from November 7-11, 2011. For details, contact Professor Suresh Aggarwal, skaggr2002@rediffmail.com

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