August 1, 2024

Uranyl Fluorescence Spectra

The idea here is to use spectroscopy to identify fluorescent mineral species via the spectrum of the light they emit when excited by UV light.

Paul Adams and Storm Sears are busy working on this in August of 2024. Paul began some work several years ago using a point and shoot camera in conjunction with a diffraction grating. Recently these two identified an affordable precision spectrometer and are pushing forward on this project.

Visible light

From 380 nm to 750 nm

BW Tech Spectrometer

These were originally used in some kind of medical device that did Raman. You can buy then for $200 on ebay from the seller "spectrophoton".

Software

Now that I have a BTC100, I am eager to also have software. I have spectrum studio. It works fine, but only works under windows. I much prefer working under linux, so I am writing my own software in python, which can also be used on Windows or Mac.

Spectragryph software

This is software for windows that many people pay to use.
More details in the following link:

Calibration sources

Using mercury lines from a fluorescent lamp works well.
Even better is to use a UV lamp in an EPROM eraser.

Laser diodes

We want to use a 405 nm laser diode source to generate fluorescence.

Thunder Optics

This (or one of their products) may be a BTC100 spectrometer in disguise. Note that "Thunder Optics" would seem to be in France based on the internet domain. Along with the spectrometer itself, you need a fiber ($50) and lens ($100), so the outlay to get started with this is $600.

They advertise a 350 to 890 nm range of wavelengths and a 1800-1200 pixel detector The device is interfaced with a USB 2.0 cable and you get a license for "Spectragryph" for personal use.

A "ghetto" spectrometer using a webcam

This seemed like a hot idea (back in 2020) before I bought the BTC100.

Illumination

Controlling the intensity of the UV illumination is important (critical) otherwise the detector in the spectrometer can be saturated.
Feedback? Questions? Drop me a line!

Tom's Mineralogy Info / tom@mmto.org