¿ªÔÆÌåÓýThanks Geo.? Yes, Dud offered to run an analysis, so I¡¯ll be dropping a sample in the mail to him so he can run an analysis.? He also mentioned checking the sample with a 405 nm laser pointer.? I did that last year when I first collected the samples, and did indeed see a similar response of both fluorescence and phosphorescence.? I¡¯d be interested to see a spectrogram of a typical 405 nm laser diode to see where its UV peaks come in.? I know many laser diodes actually produce their primary output in the infrared region, and they use a frequency-doubling ¡®filter¡¯ to ¡°boost¡± the response into the visible range.? Therefore, I can understand that a 405 nm laser diode is probably producing its primary emission at 810 nm, which would be in the infrared region and ?¡®invisible¡¯ to the naked eye.? I don¡¯t know if there is frequency tripling going on to produce a 270 nm peak, or if perhaps the ¡°blue¡± 405 nm laser diode is producing another longer wavelength peak that is being frequency-shifted into the UV region. ? Nope, never did venture into the ¡°flame speaker¡± realm.? Sounds very interesting.? What was the ¡®fuel¡¯ for the flame? Was it something like methane or propane, spiked with an aerosol of metal salts?? Or was the flame actually a plasma of ionized air or some other inert gas?? Yeah, the old days of ham radio with big iron, kilovolts, and vacuum tubes like the 807.? The noobs don¡¯t know what they were/are missing. ? Thanks for the comments, Geo.? Another member of the group, Charles Young, also offered to run an XRF analysis.? Perhaps when all is said and done, both will share their results with the group. ? 73 Geo. ? Ken, WB0OCV ? ? From: GEOelectronics@...
Sent: Saturday, November 7, 2020 04:45 PM To: [email protected] Subject: Re: [XRF] Phosphorescent Calcite ? Interesting Ken. Probably Dud's setup is the best for the light elements- but strontium is easy to do on an amateur rig, so I'll ask Nick what chemicals make red colors in fireworks. ? Which reminds me Ken, did you ever build a flame speaker? I set one up once and it was amazing. Shoot a flame between two metal screens, are biased with HV, and modulate that HV. The flame itself is spiked with a chemical salt that ionizes and is modulated in the air to create the sound. The Germans invented it, and claim almost unlimited high notes. This was long ago when ham radio was mostly still AM and every ham had HV and modulators galore. ? Geo>K0FF ? |