Improve Your Alphachron

Conventional (U-Th)/He dating treats each grain as a single, chemically homogeneous entity. The entire crystal is degassed for helium, then dissolved in acid for U and Th — and the resulting age is a bulk average across the whole grain. This approach works well and has produced decades of excellent science, but it does leave accuracy on the table. The two most common minerals measured in (U-Th)/He thermochronology — apatite and zircon — are rarely chemically homogeneous, and parent nuclide zonation is common enough that spatially resolved measurements can meaningfully improve results.

When U and Th are unevenly distributed within a grain, the helium concentration field that develops over geologic time is correspondingly complex. A bulk age integrates over that complexity, and in some cases the resulting date may obscure detail that would otherwise be resolvable. Laser ablation addresses this by sampling a precisely defined, defect-free volume of the crystal with a known surface area — overcoming two uncertainties inherent in the traditional bulk crystal method and matching spatially resolved helium with spatially resolved parent chemistry.

The RESOchron was originally developed by Australian Scientific Instruments and CSIRO, pairing the RESOlution laser ablation frontend with the Alphachron extraction line. It is now offered through Applied Spectra, Inc., who acquired the RESOlution product line. The RESOlution generates 193 nm UV light through an ArF excimer source — a wavelength that couples efficiently with silicate and phosphate minerals for clean, controlled ablation with minimal thermal damage to surrounding material.

The RESOchron uses a dedicated UHV sample cell that connects directly to the Alphachron extraction line, maintaining the vacuum integrity that helium thermochronometry demands. The laser offers spot sizes from 2 to 100 μm (squares and circles), sub-1 μm XY positioning accuracy, and homogeneous energy distribution for flat-bottomed ablation craters. Users will need to supply their own pit profiling system for characterizing ablation volumes.

Because the RESOlution is a full laser ablation frontend, it is not limited to helium work. The system can also be connected to a nearby ICP-MS and used as a standard laser ablation source for U-Th-Pb geochronology, trace-element mapping, or any other LA-ICP-MS application — making it a versatile addition to any geochronology or geochemistry lab.

Out-of-the-box Windows 11 is not suitable for unattended analytical instruments. AI assistants, telemetry, metrics reporting, and — most critically — forced security update reboots will interrupt or abort an analytical sequence mid-run. A forced reboot during a multi-day automated run is not a minor inconvenience — it is a serious headache that can set the lab back significantly. This system will never reboot itself. Updates are still downloaded and installed, but forced restarts are disabled. You decide when the machine reboots — not Microsoft.

Hard drives are encrypted with BitLocker for institutional security compliance. COM ports below 9 are reserved exclusively for Alphachron components so that Windows never reassigns them after a reboot or USB reconnect. The result is a Windows installation that behaves like an instrument PC, not a consumer desktop.

A long-standing pain point for Prisma Plus QMS users has been forced dependency on Windows 7. Pfeiffer's Quadera software — required for Prisma Plus control — was never ported to newer operating systems, leaving many labs stranded on an end-of-life OS that most institutional IT departments will not permit on their networks.

Pfeiffer's newer software, PV Mass Spec, supports the Prisma Plus hardware on modern Windows, clearing the path to a fully supported, network-compliant operating system.

The SAES AP10N MK3 that ships with the Alphachron is a capable, reliable non-evaporable getter. It handles the gas loads of a typical helium thermochronology extraction line without issue — users routinely go a year or more between activations. It is just fine.

The Gamma NEG NS series is, therefore, not a solution to any particular problem. Rather, it is an intentional upgrade for users who want to squeeze the absolute maximum signal quality out of their system. Non-evaporable getters work by irreversibly chemisorbing reactive gas species — H₂, H₂O, CO, CO₂, N₂, hydrocarbons — leaving noble gases untouched. More active getter mass means the chemisorption is more complete: a larger getter removes more of the reactive background, more thoroughly, leaving your mass spectrometer with less noise and a cleaner view of the helium you are actually trying to measure.

Where this upgrade earns its keep is in resolving ultra-low helium volumes — young samples, small grains, low-retentivity phases, anything where the ⁴He signal is approaching the baseline. Reactive gas species that survive the getter raise total pressure in the source, and higher source pressure means more coulombic repulsion between ions in the beam — scattering trajectories, attenuating signal, and degrading the ratio of helium ions that actually reach the detector. A larger getter, seated above the ion source, scrubs more of that reactive load out of the gas and keeps total pressure lower. The payoff is a quieter baseline and a stronger helium signal from the same aliquot.

The SAES AP10N MK3 uses SAES' St101 getter alloy. The Gamma NEG NS series uses a different Zirconium-Vanadium-Iron alloy chemistry, deployed at a scale that dwarfs the standard SAES getter. The sintered disc construction of the NS series provides excellent gas access to the getter material. The result is more complete reactive gas removal at every point in a run — lower H₂ background, lower CO background, lower baseline noise — which translates directly into cleaner helium measurements and tighter analytical uncertainties.

The three NS variants we offer scale up progressively in getter mass and pumping speed. All three require no power between activations and introduce no moving parts to the line.