Updated 1st August 2016

Recent updates: SwissMicros DM15 Scientific Calculator - A Ceramics and Photographic Exhibition

Photoacoustic mercury analyser working in igloo laboratory, Polar plateau, Antarctica
Photoacoustic mercury analyser working in igloo laboratory, Polar plateau, Antarctica


I retired from a science career in spectroscopy, microscopy, instrumentation and chemistry in 2010. I have a PhD and an MSc from Victoria University of Wellington.

This web site is patterned on one I created when I was working at Victoria University. That site, featuring the JEOL 733 electron microprobe, is archived here. To maintain this site I use Smultron, which is a simple Mac editor.

The notes provided here are mainly for my benefit. I find it easy to update HTML and the information is easy to find. If others can find anything useful here then that is good.

Commercial Work

Occasionally, I do commercial work related to some of the topics written about on this site. I sometimes do work for clients in the packaging industry using my skills in microscopy, electronics and mass spectrometry. I researched improvements to the lost-wax process for a Chicago manufacturing Jeweller. This work has resulted in a provisional US patent. I have also developed a simple replacement oscillator for use in plastic film thickness measuring equipment.

Scientific Instrumentation

I am still interested in developing, modifying and using scientific instrumentation and I use my electronic, mechanical and optical skills to achieve this. I have some skills in product design. Most of the instrumentation, featured on this web site, has been developed or modified by me since I retired.

Some personal experiences are also included.


Portable X-ray Spectrometer

I have mounted an Amptek X123 X-ray spectrometer on an Equipoise-lamp arm along with a shielded 1 µC 241Am source from a domestic smoke alarm. The spectrometer can be used to safely establish the presence of elements from sodium to uranium without altering or touching the sample. This is is helpful when valuable artefacts need to be studied. Any object can be studied by placing it near the detector. Many objects can yield useful results in a few minutes. Non-metallic samples may take longer. The whole system packs into a briefcase.

X-ray Spectrometer
X-ray Spectrometer

Plasma Asher

My small and novel plasma ashing system can completely ash organic samples at room temperature. There is no significant heating of the sample and ashing occurs without any pyrolysis or charring. This means that volatile inorganic elements are not lost from the sample. The inorganic skeleton of a sample can be revealed for microscopic examination. Ultra clean surfaces can be prepared using this technique. Hydrophobic plastic surfaces usually become hydrophilic. This can improve the performance of adhesives. A miniature fuel-cell based oxygen generator doubles the ashing rate for graphite to about 10mg per hour for a 0.5g sample. Cellulose ashes at a similar rate. Reversing the cell generates hydrogen, which can perform reduction reactions in the plasma. For example, the reduction of cellulose, forms an oil.

plasma asher
Plasma Asher

Macro and Microphotography

Custom designed macro and microphotography cameras have been developed for the photography of small objects. Samples can be imaged using incident, transmitted, polarised, circularly-polarised, or dark-field illumination. I also use a research class microscope with a digital camera and LED illumination.

Portable Mass Spectrometer

A portable mass-spectrometer has been built which comprises a Dycor MA200m mass spectrometer and an oil free Pfeiffer Molecular-Drag pumping station. The mass spectrometer is used for gas analysis and monitoring. The mass range is from 1 to 200 daltons. A platinum furnace is available to heat solid samples for evolved gas analysis. A membrane inlet can handle gases in liquids. This use of the Dycor mass-spectrometer solved several on-site industrial problems. A variation of this design used an ion pump and the membrane inlet. This version operated independently from mains power at a number of sites. It could be run from four car batteries for up to 10 hours a day. Wet gases or gases dissolved in liquids could be directly measured with the membrane inlet. The instrument is supported with MASSPORT software.

Mocon Thickness Profiler Repair

The repair of a Mocon profiler, which measures the thickness of multilayer plastic films, resulted in the development of a small, stable and precise replacement oscillator. The original oscillator was prone to failure and was very costly to replace.

Camera Stabilizer

An inexpensive camera stabilizer was developed to help my non-stationary hands make some watchable short videos of some of our activities, along with some still photos. The stabilizer is designed for the Canon G15 camera and it is simple and effective. It has been built in two low cost versions with one version shown at right.

Photoacoustic Mercury Analyser

I developed a novel Photoacoustic Mercury Analyser when I worked at the DSIR. This was successfully used in the measurement of mercury in a range of samples, including air, water and snow. It was used for a few seasons in Antarctica. The instrument could measure less than 1 picogram of mercury in the sample cell. Pre-concentration, using a gold collector, allowed natural mercury levels in air to be determined.

Gas Chromatograph with a Fuel Cell Generated Hydrogen Carrier

I modified a HP 5720A Gas-Chromatograph. by adding two PEM fuel-cells run as water electrolisers. Bottled carrier gases are not required. One cell supplies hydrogen as the column carrier while the other supplies make-up hydrogen for the flame ionisation detector. Either gas flow can be varied to suit the application by simply changing the cell current.

Miran Infrared Spectrometers

A Miran 1A infrared spectrometer can be used at any wavelength from 2.5 to 14.5 microns. A wide range of organic compounds in gases can be detected. The cell path can be varied from 0.75 to 20.5 metres. The official manual was missing so I wrote my own JEP Miran 1A manual. I also have a Miran 103 infrared spectrometer. This differs by having a cell with a fixed 13.5 metre path length. It uses a range of plug-in interference filters for wavelength setting. My filters allow the analysis of carbon monoxide, ethylene oxide, nitrous oxide and halothane. The operation is otherwise similar to the Miran 1A.

Lathe Milling Attachment

I have added a Dremel tool and a micrometer controlled feed adjustment to a Unimat 3 lathe. The setup allows the small scale accurate milling of alloys and plastics and is pictured at right.

iPod Nano Watch

This milling setup was used to make a backing plate which turns an iPod Nano into a watch. This item is more useful than expected. I get the time, a stopwatch, a timer, music, podcasts, iTunes U, a photo album, a pedometer, an audio recorder and a radio all on my wrist. The illuminated display is a useful torch at night.

I store notes, like medical data, phone numbers, and bus times, as the lyrics of a few memorable songs. This is a simple cut and paste operation using "Get info" in iTunes. The battery lasts a reasonable time, depending on the task. Current smart-watches display phone messages and not much else. For this my cellphone is usually nearby, in my pocket. A Warning - the display is black and under glass so the iPod can get extremely hot if worn in direct sunlight. This will likely cause damage, in my case the on/off switch became faulty from adhesive movement inside.


Giant Expressway 2 Folding Bikes

Since January 2013 I have resumed cycling using my Giant Expressway 2 Folding Bike. I purchased this Bike as an easy re-introduction to cycling and to improve my strength, fitness and balance. At the time the only folding bike that I could find locally was the Giant Expressway 2, so that was my choice. I purchased a second bike so Désirée could ride with me. Look at Dizzy's folding bike blog for details of our rides.

At Seagull Hill near Wedderburn
At Seagull Hill near Wedderburn

Tarini Mountain Bike

I have completely upgraded my old Tarini mountain bike, including rebuilding the wheels with stainless steel spokes. I first started riding again with this bike but I needed to ride on flat areas, initially. The folding bikes were more convenient to transport in our small car.

Jamis Allegro Sport Fitness Bike

I also have a Jamis Allegro Sport fitness bike to use mainly for solo road cycling. I have reviewed this bike here.

SmartMotion e20 Folding Electric Bikes

More recently we purchased two New Zealand designed SmartMotion E20 folding Electric Bikes to allow us to undertake a wider range of rides in our hilly home town of Wellington, New Zealand. The electric bikes have the added benefit of making our rides more sociable as we now ride at similar speeds. We still ride the Giant Expressways on easier routes.

Wellington from Mount Victoria
Wellington from Mount Victoria

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The name of this site adds the initials of my name, John E Patterson, to "spectro", from spectroscopy. The logo above is a stylised "JEP" with overlapping letters. The colours represent spectroscopy.

My CV is here.

Hover the mouse over a photo for a title. Clicking on a photo takes you to a related link or gives you a larger version.

Amptek X123 X-ray spectrometer Amptek X123 X-ray spectrometer

Leitz Microscope with JEPCAM Leitz Microscope with JEPCAM

Picture of Dycor Mass Spectrometer Dycor Mass Spectrometer

Camera Stabilizer Camera Stabilizer

Sampling air for mercury at Lake Vanda Sampling air for mercury at Lake Vanda

Black flame - Sodium lamp behind Black flame - Sodium lamp behind

Halley's Comet Halley's Comet

Unimat 3 - Dremel 300 milling modification Unimat lathe, Dremel 300 milling modification

Ipod Nano watch Ipod Nano watch

Pencarrow Head, Wellington Pencarrow Head, Wellington.

Tarini Mountain Bike Tarini Mountain Bike - Wellington

Tinakori Hill - Wellington Tinakori Hill - Wellington