added images of sample chambers

NGMS.qmd

@@ -10,10 +10,12 @@ Noble gas mass spectrometry
 
 ## Gas Extraction and Sample Preparation
 
-In order to measure noble gases, we first need to extract them from some sample material (solid, liquid, or gas) and, to the best of our ability, isolate the noble gas element we are interested in measuring from all of the other extracted gases. Because of this, essentially all noble gas mass spectrometer (NGMS) systems have what we call an extraction line in front of the ion source. This extraction line will look different in detail in every NGMS laboratory, but it will generally consist of a network of volumes (e.g., tubes, bellows, cans) that are interconnected to one another via valves that enable different volumes to be isolated from one another. Internally, this network of volumes and valves will be comprised entirely of metal that can be heated or "baked" to relatively high temperatures (ie., hundreds of degrees C). This "baking" processes facilitates the release adsorbed gases from the internal components so they can be pumped  away, enabling the NGMS extraction systems to achieve ultra-high vacuum (UHV) conditions with minimal contributions from gases that are not derived from the samples themselves. Below, we describe how gases are extracted and then processed within this UHV extraction system before being let into the NGMS itself.
+In order to measure noble gases, we first need to extract them from some sample material (solid, liquid, or gas) and, to the best of our ability, isolate the noble gas element we are interested in measuring from all of the other extracted gases. Because of this, essentially all noble gas mass spectrometer (NGMS) systems have what we call an extraction line in front of the ion source. This extraction line will look different in detail in every NGMS laboratory, but it will generally consist of a network of volumes (e.g., tubes, bellows, cans) that are interconnected to one another via valves that enable different volumes to be isolated from one another. Internally, this network of volumes and valves will be comprised entirely of metal that can be heated or "baked" to relatively high temperatures (ie., hundreds of degrees C). This "baking" processes facilitates the release adsorbed gases from the internal components so they can be pumped  away, enabling the NGMS extraction systems to achieve ultra-high vacuum (UHV) conditions with minimal contributions from gases that are not derived from the samples themselves. Below, we describe how gases are extracted and then processed within this UHV extraction system before being let into the NGMS itself. 
 
 For solid samples, gas extraction is most often achieved by heating a sample up under ultra-high vacuum (UHV) conditions. Heating methods have evolved over time. Early on, heating was most often carried out by dropping samples into a resistance furnace. Today, many laboratories heat samples using what is sometimes called a "laser microfurnace": a sample is placed inside an UHV chamber with some form of transparent window, and the sample is heated through the window using a laser. The type of window, type of laser, and sample-laser coupling is highly application specific and will be discussed later. 
 
+![*Examples of laser microfurnaces used for noble gas extraction systems. Left: Laser microfurnace used with an infrared wavelenth diode laser. Right: Laser microfurnace used with a CO2 laser, not under vacuum.*](figs/NGlasermicrofurnaces.jpg){fig-alt="Examples of laser microfurnaces used for noble gas extraction systems."}
+
 In addition to heating, there are some niche gas extraction methods from solid samples; for example, the noble gas laboratory at ETH Zurich has a gold metal extraction line that enables them to dissolve silicate minerals in the UHV with hydrofluoric acid. However, the dominant technique is still heating.
 
 <!---