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Updated 2x2 SiPM Array
11/24/2023 at 17:30 • 0 commentsJust did a quick rework of the 2x2 MicroFC SiPM array PCB, added the temperature compensation from the single PCB and cleaned up the layout in general. It's now 2x2cm in size and still keeps the easy solderability for the four SiPMs (results in a fill factor of ~40%), while also adding the ~21mV/K slope for the power supply.
Front side with only the four SiPMs If you want to use it, just connect your power to the "VCC" pad, ground to "GND" and then the SiPM anodes to the spectrometer. You can check the set voltage at the "C" pad on the PCB. If you don't want to use the extra circuitry, you can just solder your power straight to the "C" pad and not bother with the other circuitry. However, you'll still have to solder the low-pass filters for each SiPM, otherwise they won't work.
You can find all the files here: https://github.com/OpenGammaProject/MicroFC-SiPM-Array-Board
Let me know what you think!
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New hardware revision?
09/20/2023 at 15:55 • 0 commentsTo break the silence, here is a short update on what's going on behind the scenes right now.
At the moment we're looking into a possible hardware revision 4. This one mostly focusses on the PCB and component layout to improve shielding and optimize the total device size. There is a lot that can still be done in this regard and we'll test it thoroughly before release. In the best case this will keep on improving the energy resolution of the device and the new revision will also include some smaller quality of life improvements. Follow the project so you don't miss out on any updates.
On another note, the OGD is sold out on Tindie, so thank you all for your interest in this project and the support. You can still get some of the Tiny MicroFC breakout boards if you want, the sale is still on until the end of september.
Cheers!
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End Of Summer Sale
08/31/2023 at 09:51 • 0 commentsFrom September 1st to 30th there will be a site-wide sale (-10%) on my Tindie Store, including the Mini SiD, the Tiny MicroFC SiPM breakout board and the Open Gamma Detector. No limit on the number of uses or products!
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Tiny SiPM Boards on Tindie
08/22/2023 at 10:37 • 0 commentsFinally, the Tiny MicroFC SiPM breakout/carrier boards are now available on Tindie! I have added some volume discounts for the PCBs and purchase options together with the Mini SiD and Open Gamma Detector.
Link to the store page: https://www.tindie.com/products/31304/
Thanks to all the feedback and demand from you guys for the SiPM carrier boards. It's been long overdue to add these to Tindie so that you can get the PCBs together with the detector electronics.
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Improved Case
08/19/2023 at 12:33 • 0 commentsHere is a new and updated case design for the Open Gamma Detector Rev.2 and 3!
It's a lost more compact and features friction fit slots for panel and display mounts. There are STL files for a default display mount for an SH1106 1.3 inch OLED screen and one for a solid panel cover. You can design some custom parts to fit your needs, especially with the front panel, and then just slot it right in.
The detector main board is screwed in the bottom plate that is then attached to the top. All the screws are designed to be screwed into inserts and the large front section of the case can fit up to a 5x5x5 cm scintillator.
Just uploaded all the STL files to GitHub!
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Temperature-compensated SiPM carrier board
07/26/2023 at 18:19 • 0 commentsHi there!
Here is a new and updated revision of the MicroFC SiPM carrier board: It now has some extra circuitry for temperature gain compensation! The overall size of the PCB and the solder pads have not changed at all and the bias filtering is also still on there. In addition to that, you can also use it without any of the additional electronics on it too. Don't need temperature compensation or any of the filtering? Just leave out all the components on the back side and solder directly to the anode and cathode pads for the SiPM.
If you do want to use the compensation circuit, a new BOM, Gerber file and schematic have been uploaded to GitHub. Kitspace should update too in the next couple of days (hopefully). Here is a link to the repo: https://github.com/OpenGammaProject/MicroFC-SiPM-Carrier-Board
It works completely passively without any sort of user intervention. It's based on an NTC thermistor that sits on the back side of the PCB, which is a big plus for temperature accuracy since it's on the same board as the SiPM. It's also low-power enough so that there is no unnecessary self-heating of the PCB. Just be sure to increase the SiPM PSU voltage a little bit as the compensation circuit initially drops a couple of 100mV to increase the temperature range without any need for readjustment. And ideally, you'd want to set the correct voltage at around normal ambient temperature for the correct tracking range (e.g. ~29.5V @ 25C).
Most of the research and testing has been done by Sebastian D'Hyon, so big thanks to him.
Finally, here are some screenshots on what the new board looks like:
Cheers!
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FW 3.5.1: Tiny update
07/23/2023 at 17:15 • 0 commentsHi there! Just wanted to let you know about the latest update.
This new version mostly just reduces code size and efficiency in the Arduino sketch. There are no changes on the usability part or the handling of the device in general. I dropped the akkoyun/Statistical library in favor for the more specific RobTillaart/RunningMedian lib. It's just a lot better suited for the job and will be even more handy in the future.
Cheers!
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FW 3.5.0: Quality of life update
07/07/2023 at 17:44 • 0 commentsHi everyone,
this newest firmware version is another quality of life update that improves general usability and a lot of the behind the scenes code. Most of the changes include the following:
- Almost 10% reduction in energy consumption (this result has been tested with an SSD1306 OLED)
- Slightly better timing accuracy with Gamma MCA: a few % less standard deviation for the cps value due to more accurate scheduling.
- The geiger mode display will now show the unit "kcps" if the measured cps is higher than 1000. This helps a lot with the limited line space and should be enough for most use cases.
- Possibly better higher cps behavior (not tested yet), because the first CPU core is now entirely free to process interrupts only. No other tasks run on this core anymore.
Enjoy!
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Project Showcase
06/21/2023 at 12:57 • 0 commentsAs far as I remember, I never really did a project showcase. However, there are already some pretty awesome projects out there, so I figured you'd be very interested! ;)
This one's two beautiful portable devices built by user dc1rdb, one larger unit with a 1x2 inch NaI(Tl) scintillator and the other one a little bit smaller in size with a 1x1 inch crystal. The 3D printed handle and OLED mount are a great fit for this kind of thing and can be found on thingiverse. Also, look at these awesome buttons! He's also using the 2x2 6mm MicroFC SiPM array board with great results. He built both of these units with a battery and a buzzer with a little bit of custom soldering and the built-in software support for these parts. For charging the LiPo batteries, there's a standard USB charger PCB on the inside, that's wired up to the breakout pins on the Open Gamma Detector.
That way, you can have a standalone device with recharging and not worry too much about any cabling. Let me know what you think about these! :)---------- more ----------He posted on GitHub and the Gammaspectacular forums if you want to interact with him:
PS: The 6mm MicroFC SiPM carrier boards will hopefully be available on Tindie very soon as a standalone offering and also in combination with all my other boards.
Cheers!
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New MicroFC Carrier Board
06/12/2023 at 20:03 • 0 commentsJust released a new, extra small carrier board for the 6mm MicroFC SiPMs. It's only 10x10mm in size with the SiPM on the front side and all the solder pads + an optional RC low-pass filter on the back. Usability-wise it's exactly the same, but it's smaller! That makes it A LOT easier to use on small scintillator crystals.
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Link to the new GitHub repo:
https://github.com/OpenGammaProject/Tiny-MicroFC-Carrier-Board
Kitspace should be up soon, too!