What I want is pretty simple, I am looking at more metrology than analysis, I want to use it to measure transmission and reflection of thin films to make dielectric bandpass filters and mirrors. I really could use sub-nm resolution which I should be able to get out of this spectrometer and which is a little tougher to do on the CCD units. Plus with a PMT you dont need to worry about cooling or noise quite as much.
I am using a Hamamatsu HC120 PMT module like this, only the window is on the large face, not the end: http://www.digchip.com/datasheets/parts/datasheet/190/HC120-01-pdf.php So my idea of it working is it would make two scans, the first would be to adjust the gain. As it would scan it would watch for the ADC getting maxed out and then lower the high voltage on the PMT through the HV control lead until it is within scale. Once it passes through the scan it would scan again at that voltage setting. For the data, I dont care so much. It could just be CSV and dump it into excel or sheets. But if it could be made into a compatible dataset for the other spectrometer projects out there then this could be useful for more people. I also have one of these monochromators that this guy used to make a spectrometer with. https://www.youtube.com/watch?v=veETVeEsaNM&feature=youtu.be I was hoping he would post the code but he never did. I dont think you will get far with a PIN diode. There are detectors out there to replace SiLi, the Silicon Drift Detectors, but they are still thermoelectrically cooled and $$$. I can get 50L of LN2 for about $20 so that works fine for me. http://www.thermoscientific.com/content/dam/tfs/ATG/CAD/CAD%20Documents/Application%20&%20Technical%20Notes/Microanalysis%20and%20Electron%20Microscopy/TN52342_E_0512M_SiliconDrift_H.pdf I live in Beaverton by nike. -Jerry > On May 21, 2015, at 12:43 AM, Nathan McCorkle <[email protected]> wrote: > > On Wed, May 20, 2015 at 1:57 PM, Jerry Biehler <[email protected]> > wrote: >> Would anyone be interested in helping me build a controller for a >> spectrometer? I have a Spex 1681B, it is pretty simple, step/direction >> pulses control the scan with limit switches and then an analog signal from >> the photomultiplier tube. Hardware I can do, software, not so much. Figure >> use one of their edisons. >> >> http://www.horiba.com/fileadmin/uploads/Scientific/Documents/OSD/1681340E340S.pdf >> >> -Jerry >> > > I'd be up for helping you out, but I can't this weekend... too much > going on. What did you have in mind other than telling your hardware > to scan the monochromator and (presumably) grab ADC readings? > > I had been working on this a while ago, for the CCD array spectrometer > I was working on... but I didn't have much direction other than for > data collection and doing pH experiments (I was in a chemistry class > at the time I started writing the software): > https://github.com/nmz787/open-spectrometer/tree/master/desktop-software > > Plotting the data is achievable with many different solutions, and > since writing the above code, I feel matplotlib isn't a great choice. > It looks OK, but not amazing, and I've heard the library isn't > particularly well written, and I know it's not great to try embedding > into other GUIs. > > There's also Public Lab's Spectral Workbench, but I don't really know > what it can and can't do... I feel like it's pretty tied into their > spectrometer, and I don't know if they have things like beer-lambert > calculations built in. > > > What really interests me is some kind of machine learning on spectral > data, to match a given spectrum to a library of data. This is where > the big money spectroscopy companies shine, and what really > differentiates them compared to other hardware producers. > > > Anyway, I want to get together with you to talk > SEM/High-Voltage--low-noise stuff sometime anyway. I've been thinking > of a way to do EDX too, but using a PIN photodiode instead of a SiLi > detector. In theory it should work, but with less resolution, and I'm > guessing probably less signal-to-noise (so would require long scan > times, another guess). I was planning on using an LPC4370 with it's > 80MHz ADC on it... but not sure that will be enough bits, and it's a > good amount of work to get up and running (I only started about a year > ago and then got busy and distracted with how hard it was to really > get some steam up with it). > > I'm out in Hillsboro most of the time, if you're ever out this way, > drop me a line. > _______________________________________________ > dorkbotpdx-blabber mailing list > [email protected] > http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber _______________________________________________ dorkbotpdx-blabber mailing list [email protected] http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
