All-In-One Gamma-Ray Spectrometer

Description

Using a small custom PCB with a Raspberry Pi Pico microcontroller, a scintillator (typically NaI(Tl)) and a silicon photomultiplier (SiPM) you can build your own gamma spectrometer! The needed processing and multi-channel analyzer are all on-board so no external parts are needed, except something to look at the data (with a screen, obviously).

This detector uses a silicon photomultiplier (SiPM) instead of the usual photomultiplier tubes that are more common with these types of DIY projects. This means that the whole assembly is much smaller and also safer, because no high voltages are needed! Also in contrast to projects like theremino you don't strictly need a computer or even an external sound card -- everything is self-contained. You can do standalone measurements using only a USB power cable and save the spectra to the Pico's flash storage or connect to your PC via the Serial-over-USB connection.

Details

Here are some of the most important key facts:

Compact design: Total size 120 x 50 mm. Approx. 70 x 50 mm area for electronics and additional 50 x 50 mm to mount a scintillator.
All-in-one: No external parts (e.g. sound card) required to record gamma spectra.
Easily programmable using drag-and-drop firmware files or the standard Arduino IDE.
Low-voltage device: No HV needed like with photomultiplier tubes.
Can use SiPMs in the voltage range of 27.5 V to 33.8 V.
4096 ADC channels with built-in 3 V voltage reference.
Energy resolution of ~8% @ 662 keV possible; highly dependent on your SiPM/scintillator assembly.
Default (Energy) Mode: About 15 µs total dead time while measuring energy.
Geiger Mode: About 5 µs total dead time without energy measurements.
Low power consumption: ~25 mA @ 5 V with default firmware.
Additional broken-out power pins and I2C, SPI and UART headers for custom parts (e.g. display, µSD card, etc.).
Built-in True Random Number Generator.
Simple OLED support out of the box (SSD1306 and SH110x).
Built-in customizable ticker support.

More information can also be found in the GitHub repository...

Ok nice, but how do I get it?

DIY version: Download BOM and Gerber files or use Kitspace.
Buy a complete board: Head over to Tindie.

The principle of operation for the detector looks like this:

Files

BOM.csv

BOM for the detector board

ms-excel - 2.03 kB - 04/11/2023 at 21:03

Download

schematic.pdf

Schematic of the detector board

Adobe Portable Document Format - 115.81 kB - 04/11/2023 at 21:03

Preview

Download

Components

1 × Raspberry Pi Pico Microcontroller and heart of this detector

1 × MicroFC-60035 SiPM The silicon photomultiplier used with the scintillator

1 × Main detector PCB Production-ready gerber file in GitHub repo or Kitspace

56 × Components main detector board See BOM for exact parts

1 × Scintillator For example NaI(Tl)

Project Logs

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FW 3.4.0: SH1106 support + ticker changes
NuclearPhoenix • 7 days ago • 0 comments

Hey there,

you might have already seen the new firmware files on GitHub. With this new update, I added support for the SH1106-type OLED displays. This expands on the current support of SSD1306 screens.

Also, in this update I changed the way the ticker works in order to accomodate higher count rates. The way it used to work is by clicking on each and every detected pulse. This way, you could only go up to around 1000 cps until the buzzer just saturates. Also, due to the already high activity at background radiation (>20 cps or so), detecting changes was a bit harder.

That's why the ticker now only clicks at every 10th detected pulse. That way, you can get up to 10x the range for the buzzer without saturating. Also, stock background clicks are now way more relaxed.

https://github.com/OpenGammaProject/Open-Gamma-Detector/tree/main/software
Calibration for newcomers
NuclearPhoenix • 7 days ago • 0 comments

Most of you will already know this, but for newcomers, here is the essence of how to calibrate the Open Gamma Detector. If you have your complete device with a scintillator, you only need a sample that has well-known gamma-ray energies. You can use these to calibrate the bin axis and then export the calibration.
In this video I'm using two tiny LYSO scintillators as a Lu-176 source. This isotope has two very well-known gamma peaks that are ideal for a very simple linear calibration.
FW 3.3.0: Ticker support
NuclearPhoenix • 05/15/2023 at 16:59 • 0 comments

The newest firmware version adds support for a buzzer to be used as a ticker. If you're used to commercial (mobile) devices or ever heard a Geiger counter clicking, you'll feel instantly familiar with the sound. This way, the count rate can be translated into an audible tone with which you can easily (only roughly of course) assess your surroundings.
Just connect your (passive!) buzzer between one of the broken-out digital pins and ground and enable the ticker in software. By default, digital pin 9 is used for this job ("RX" pin header), which obviously means that you cannot use the hardware UART connection and the ticker simultaneously. This pin assignment can be changed from within the Arduino IDE sketch.

The default PWM frequency for the buzzer is 3 kHz, which you can also change in the sketch. The actual click duration per gamma pulse can be set in runtime via the "set ticker <integer>" serial command. The number will set the duration in milliseconds. I'm using just "1" here, it's more than enough for me. This also means that audio output will saturate at 1000 cps in the worst case.
I also added new metrics to the device info page: "power cycle count" and "power-on hours". These are pretty much self-explaining and log the number of device reboots as well as the running time of the device in hours. They are logged in another file inside the same file system as the settings and only update at the device start and after every full hour of runtime.
Have fun!
FW 3.2.1: Stability Update
NuclearPhoenix • 05/06/2023 at 19:15 • 0 comments

This firmware update should improve overall device stability (random crashes) and fixes an issue with the histogram data output ("set out spectrum") to Gamma MCA. You'll be able to use this output mode now whilst also having the display in "spectrum mode". There should no longer be any issues there.

Other than that, nothing has changed and the dead time is still the same as with the last update that seemingly introduced some of these problems.
https://github.com/OpenGammaProject/Open-Gamma-Detector/tree/main/software

Have fun!
FW 3.2.0: More faster = More better
NuclearPhoenix • 04/29/2023 at 19:50 • 1 comment
This update is a bit larger and arguably more important than the last one. There are mainly two pretty large improvements: one on the detector dead time, the other on the display in Geiger mode. Until now it used to show the standard spectrum screen, only that there was in fact no spectrum, but one peak at channel 0. That has finally changed!
Here is a list of changes as always:
- Much faster and more stable interrupts for an improved dead time and less error peaks at the lower ADC bins. I re-evaluated the dead time and it looks like almost 10 µs faster than before in both modes (set averaging 1). That's a huge improvement! As a result of that, the detector also performs much better at higher count rates (>10k cps).
- Pressing the BOOTSEL button on the Raspberry Pi Pico now switches between Geiger and energy measurement modes.
- Geiger mode now has its own little OLED interface with more info about the current counts per second. This could be temporary and there might be a new screen in the future with more features.
- "Read info" command also lists the total number of detector impulses, i.e. the total counts.
New geiger mode OLED interface (excuse the grainy photo, my phone's pretty sh*t)

All the uf2 files for you to update the device can be found on GitHub right now. If you have any questions, suggestions or issues, feel free to send me a message or create an issue on GitHub.
Performance w/ array board
NuclearPhoenix • 04/27/2023 at 15:14 • 0 comments

Some new tests are out with the latest MicroFC SiPM Array Board. It features a 2x2 grid of the standard MicroFC 6mm SiPMs resulting in a much larger active area compared to the single MicroFC carrier board. It's not much bigger in size too, so the ratio of active/total area has improved a lot!
You can get an output of each individual SiPM or just connect all of them in parallel via a jumper on the PCB. If you do that, you can use the board just like a single SiPM -- your detector won't know the difference. Using this "parallel mode" you can use the board with the Open Gamma Detector without any modifications.
All the hardware is fully open-source of course, head over to the GitHub repo for some more info: https://github.com/OpenGammaProject/MicroFC-SiPM-Array-Board

Finished assembly of the 2x2 array board.
Read more »
Firmware Version 3.1.0
NuclearPhoenix • 04/21/2023 at 19:17 • 0 comments
Just released a new firmware update with some nice improvements:
- New console function "set correction <toggle>" to manually disable the CPS correction. As described on GitHub, the 4 faulty ADC channels are discarded, but in order to not falsify the CPS measurement, they are appended to channel 0 again. However, this often leads to the vertical scaling in Gamma MCA not fitting correctly to the overall spectrum. Therefore, the correction can now be deactivated. The 4 channels are ignored anyways, so you will read ever so slightly lower total cps if you enable this function. (does not apply to geiger mode)
Comparison between having the correction enabled and disabled with regards to the vertical scaling.
- Lots of bug fixes in the settings. If something doesn't work right away, I can only recommend that you reset the settings once and reboot the device.
- Bug fix for the DC bias subtraction which could lead to an integer overflow.
Enjoy!
FW 3.0.1
NuclearPhoenix • 04/18/2023 at 14:15 • 0 comments

Just release a new firmware update for the detector! I implemented a ring buffer for the measured activity, i.e. the cps values that will be shown at the top of the OLED screen. It keeps track of the average activity of the last 5 seconds and will update much quicker to higher or lower count rates than before.
The way it was implemented before was just by adding up all the pulses in the spectrum and then dividing by the time it took to collect them. That made keeping track with high cps very unstable and made it almost impossible to change the value after letting it run for a long-ish time, i.e. it was extremely sluggish.
The displayed spectrum hasn't changed and still keeps running until a set number of pulses has been registered. The time it takes to do this is shown in the top right corner. Display refresh time is still one second by default.
Update files can be downloaded on GitHub: https://github.com/OpenGammaProject/Open-Gamma-Detector/tree/main/software
Kitspace Updated
NuclearPhoenix • 04/15/2023 at 18:00 • 0 comments

Just a quick update that the kitspace files are now all updated to the 3.0 revision and ready for production. Have fun!
https://kitspace.org/boards/github.com/opengammaproject/open-gamma-detector/
Here comes 3.0!
NuclearPhoenix • 04/11/2023 at 20:56 • 0 comments
Finally, the newest hardware revision of the Open Gamma Detector is ready! All the testing and most of the work is done now, so here you have it. I'm so excited to share all the things that I improved with you.
Long story short, here is the (complete) list of changes between 3.0 and 2.x:
- Got rid of the extra SiPM PSU pot.
- Removed the gain pot, it's fixed now which greatly helps with getting it to run in the first place. If you're using a crystal size that fits well on the PCB scintillator area (i.e. not larger than the PCB, but not tiny either), you shouldn't need to change any gain parameters anyways. However, if you really want to change it, there is documentation on how to do it.
- Turning any pot on the board clockwise will always increase the parameter, anti-clockwise decreases.
- Voltage reference for the Pico ADC is now soldered by default.
- Switch to 0603 components for a much improved PCB layout and better performance. Don't worry, future revisions won't get smaller than that and it's still fairly solderable by hand.
- Slightly larger SiPM output voltage range.
- Slightly larger energy range due to optimized diode selection for the peak and hold circuit.
- More optional pin headers for SPI, I2C and even UART.
- Ability to subtract the average baseline voltage, i.e. the DC bias on each signal peak akin to something like hardware AC coupling.
- Voltage reference for the threshold comparator voltage for even less drift.
- More power filtering in general.
- The threshold triggers now directly on the signal instead of the peak and hold circuit, which makes it much more reliable.
- The forward four screw mounts are now connected to the circuit GND if you want to shield your detector board.
- Added a dim-but-visible power LED.
- Removed the extra cable tie holes. These were way too small anyways in my experience and you don't really need them.
- Much improved silk screen design in my opinion.
- Optimized component values (e.g. all voltage dividers) for power usage.
- Added input protection diodes.
- Cleaned up the software with some hard-to-understand settings removed.
- Much improved documentation on GitHub with cleaner READMEs and more Q&A.
It's really hard to remember and write down all the changes that I did in the last couple of months, so if I forgot something, I'll add it to the list, don't worry! ;-)

As you can see the focus really has been on the versatility, ease-of-use and also on the performance (energy resolution) and I think these changes all speak for themselves. It's a large step forward in the right direction, without having to increase the total parts cost much at all, even in the current time.

Here is a really quick spectrum to give you an idea on the improved energy resolution, although I have posted it a couple times now already:

30 minute spectrum of Lu-176

As always, fully assembled boards will be available on my Tindie store (linked on the project page or on GitHub), as well as the Makerfabs store. I had to increase the price by USD 5 unfortunately, that mostly goes to covering all the fees on Tindie and PayPal and a small fraction also goes to a slightly higher production cost.

You are as always encouraged to build a device on your own, remix the design or whatever you can think of! Buying assembled boards from my store saves you some time soldering all the parts and at the same time you support me with the purchase, I really appreciate it!

In addition to this, I will be releasing the newest revision of the Mini SiD with much improved performance there as well in the next couple of days, stay tuned and have a nice day!

View all 33 project logs

Build Instructions

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OPTIONAL: Solder SiPM carrier board components

This is an optional step if you're using the carrier boards. If you're not and just soldering wires directly to the SiPM or doing it otherwise, skip this part. Note, however, that soldering wires to the SiPM itself is much harder than using the breakout board.

You can choose to add the optional SMD components, to add some more power decoupling. This might help stability especially for longer cable lengths. If you're doing so, bridge the solder jumper and connect wires to VCC, GND and A(node) pads. If you're not using the SMD parts, solder directly to A(node) and C(athode) and the jumper remains open.

Couple SiPM with scintillator

Center the SiPM on the scintillator crystal and put some silicon grease or other special coupling material between the two parts to optimize the optical coupling (and minimize reflections).

Wrap scintillator assembly

Use black electrical insulation tape or similar non-transparent material to wrap the whole assemby, but watch out for the cables, of course. This will reduce light passing to the SiPM to an absolute minimum, otherwise it won't work properly. You should use multiple layers of tape just to be sure.

Tip: I'm using tightly-wrapped Kapton tape on the outer-most layer to avoid the insulation tape from getting too loose.

Discussions

gasel86895 wrote 04/22/2023 at 17:31

Hi, this is very interesting. I would like to understand your thinking in the preamp design and why a transimpediance preamp design wasn't used.

Are you sure? yes | no

NuclearPhoenix wrote 04/22/2023 at 21:00

Hi, yeah I get this question a lot. In a nutshell, it boils down to saving cost and complexity. You could do that of course and it might (?) improve energy res by a couple %, but you'll pay that with multiple times the cost and complexity. That's just not worth it for this kind of device IMO.

Are you sure? yes | no

NuclearPhoenix wrote 04/23/2023 at 10:53

Just added a new FAQ section on the design/cost thing if you want a more detailed explanation: https://github.com/OpenGammaProject/Open-Gamma-Detector/blob/main/REFERENCE.md#why-dont-you-use-a-tia-or-csp-or-change-x-or-y

Are you sure? yes | no

Sebastian D'Hyon wrote 04/20/2023 at 08:06

Hey, awesome project!

Any chance for a .step file for the PCBs? Would like to do some modelling for a custom case and shielding. I'll share whatever I make.

Are you sure? yes | no

NuclearPhoenix wrote 04/20/2023 at 08:55

Hm, I don't think EasyEDA supports STEP exports. But I can give you .mtl and .obj files. Let me know if that works too!

Are you sure? yes | no

Sebastian D'Hyon wrote 04/20/2023 at 10:11

This will work!

Are you sure? yes | no

NuclearPhoenix wrote 04/20/2023 at 11:46

Just uploaded it to GitHub! https://github.com/OpenGammaProject/Open-Gamma-Detector/tree/main/enclosure/3D

Are you sure? yes | no

sukhjinder564 wrote 03/31/2023 at 16:27

Hi, I am trying to flash my pico with the firmware you have provided, but it does not reboot once I drag the .uf2 file over in Windows. I tested a simple LED blink program using MicroPython to confirm that I can communicate and run something on the Pico. Do you have any idea what may be occuring?

Are you sure? yes | no

NuclearPhoenix wrote 04/02/2023 at 11:53

Hm, that's weird. So the micropython sketch works fine?

What UF2 file are you using specifically?

I'm not sure what could possible be causing this, especially since you had success with micropython. Did you flash the micropython firmware previously and then upload scripts via thonny or something like that?

Are you sure? yes | no

sukhjinder564 wrote 04/03/2023 at 17:18

I was able to flash the board after compiling the sketch on your git, but the provided .uf2 file does not work. Not sure why. I had been using thonny previously.

I have been noticing that the noise on the SiPM comes in at high energies (~600 keV!) - I cannot see the Cs137 peak well and cannot see the 511 peak in Na22. The assembly is light-tight, and I have adjusted the gain as well. Do I need to have a 50 ohm resistor on the anode? I currently have four wires soldered directly to the SiPM that are being fed into the PCB.

Are you sure? yes | no

NuclearPhoenix wrote 04/04/2023 at 10:34

Okay, that is very weird. Especially since all the Arduino upload does is generate a UF2 file, reset the device and copy the UF2 to the device folder. So it's basically the same.

Anyways, did you calibrate the device with some known isotopes? Because the raw output you get is just the ADC channels, i.e. bins.

Are you using the SiPM breakout board? And what cables do you have connected? You only need 3 at max, one for anode, cathode and a ground.

You don't need any additional resistors.

Can you maybe send me a PM with one of your spectra please, where I can see the noise peak?

Are you sure? yes | no

sukhjindersingh564 wrote 01/25/2023 at 19:37

Hi, this is a very interesting project.

I am having trouble finding any of the C-Series SiPMs in stock, do you think one of the J-Series SiPMs is a good alternative? For example the MICROFJ-60035-TSV-TR1?

Thanks!

Are you sure? yes | no

NuclearPhoenix wrote 01/27/2023 at 11:28

Hi, just had a quick look at it and it seems like it would work. They look mostly similar to the C-Series SiPMs.

Another alternative for you would be the Broadcom Avago AFBR-S4N66C013.

I also have a breakout board for this: https://github.com/OpenGammaProject/AFBR-SiPM-Carrier-Board

Are you sure? yes | no

Fabian Meier wrote 12/19/2022 at 09:01

Need some pointers in getting started with board from Makerfabs.

Hi NuclearPhoenix, great project - thank you very much for your time and effort.
I ordered a board from Makerfabs. I don't get any connection via USB - I don't see a serial port nor a USB flash drive (also by holding down the BOOT key). The LED ACT on the analog board is always on, I have about 20V on the PWR pin for the detector. It seems the RPI Pico board is not responding as it should. Did Makerfabs already download the Gamma Ray firmeware to the RPI? Thank you!

Are you sure? yes | no

NuclearPhoenix wrote 12/19/2022 at 11:52

Hi,

there is no firmware pre-flashed. It should pop up as an external drive as soon as you first plugged it in. Very weird that it doesn't react at all! If you press and hold the BOOTSEL key _while_ plugging it into the USB, your computer also doesn't recognize any external drive? Do you have any other Pico at hand to test it on that one, just to exclude any issues related with your computer?

If not, please hit me up with an email and maybe attach some photos of the board too.

Are you sure? yes | no

Erhannis wrote 12/16/2022 at 22:04

Questions! You mention it being sensitive to EMI - is that just the main board, or the SIPM, as well? Could you put the main board in a box and wrap it in foil, and have the SIPM on an external cable? Would having a long cable (maybe a meter?) between the main board and the SIPM introduce a lot of noise or other problems? Thanks!

Are you sure? yes | no

NuclearPhoenix wrote 12/17/2022 at 13:24

It's the main board and the SiPM as well. I wouldn't recommend long cables at all, except for shielded coaxial cables. Best case would be everything inside a grounded thin aluminium enclosure with as short cables as possible to the SiPM.

Are you sure? yes | no

Chris wrote 09/15/2022 at 20:12

Hello NuclearPhoenix,
can I also connect a PMT with a NaI(Tl) scintillator? I will use a HV Splitter, so that only the pulse signal after the splitter can reach the signal input circuitry of your board.

So I mean can I replace your SiPM detector board with a PMT detector? If yes what will I have to care about?

Are you sure? yes | no

NuclearPhoenix wrote 09/15/2022 at 20:51

Hi, if you manage to supply the detector board with positive (!) pulses from your PMT you could get this to work. I don't know the voltage (signal) levels you're dealing with in your setup of course, so definitely watch out to not kill the preamp by overvoltage. Absolute maximum rating is -0.5 to 3.8 V in this case, preferably 0 to 1.6 V.

Definitely let me know if you manage to get some results, sounds really interesting!

Are you sure? yes | no

Chris wrote 09/15/2022 at 21:06

Hi, I had ordered the PMT and NaI(Tl) scintillator crystal from different sources. The HV power supply I am using can be regulated from DC to 1000V with a maximum of 2 mA. That should be enough to drive the PMT. It has a power divider at its end and needs only a HV supply of appr. 850 V for working. After that there will be a HV/signal splitter which separates the HV and the signals. I have to measure the signal level if I received both items and build together. I am happy to write the results here in your blog. Your board is already here (orderered from Makerfabs). They are really quick in shipping. After 7 days I received the board completey really professional build. Thumbs up!

Are you sure? yes | no

Chris wrote 10/23/2022 at 16:30

Hi, now I got my NaI(Tl) Scintillator crystal and build als parts together for my PMT sensor. After calibration of my signal inverter amplifier (build in a shielded Al-housing with high qualitiy BNC connectors from huber & suhner) I played a while around with the trimmer settings till my scop says that the voltage peaks amplitudes are in the range of 400 mV to 1,9 Volts. Yess it runs!

Your Open Gamma Detector is showing cps rates... I have to reduce the PMT Voltage from 850 to 760 Volts, because NaI brings much more higher pulses as Bicron 412 Scintallators. That is impressive. The whole system seems to work now and I am playing with your Gamma MCA...

Fantastic project! Respect!

If you want I can post the hardware mods so that other interested readers can adapt it to their own PMT.

Are you sure? yes | no

NuclearPhoenix wrote 10/23/2022 at 17:48

Awesome! Don't forget to turn down the preamp gain on the board if your input signals are already at 100s of mV, but best not all the way. You could also desolder one of the 10 Ohms feedback resistors next to the preamp to get a gain of 1 and fully turn down the potentiometer. This way you'll probably get the best range for your setup. Signals could then start at ~100 mV up to the 1.6 V max.

Please feel free to post more info on your hardware, I'm interested ;)

Are you sure? yes | no

Jesse wrote 09/03/2022 at 13:27

Awesome little project, I work at a university in the nuclear engineering department but am not very strong in the EE area. I ordered one of the boards but I'm still looking for a SiPM chip. It appears all possible sources are back ordered. Would the evaluation board (MICROFC-SMTPA-60035-GEVB) be an appropriate substitute, it looks like these are still available?

Thank you and keep up the great work!

Are you sure? yes | no

NuclearPhoenix wrote 09/03/2022 at 15:59

Hi there, thanks for your comment and encouragement ;)

The MICROFC-SMTPA-60035-GEVB should work no problem, you'll only need pins 1 and 3 on it. The only issue might be the pin headers, though. I can't really tell from the images, but on the front side the solder joints could be actually higher than the SiPM itself so you wouldn't get any optical contact with the scintillator. Other than that you need to get it light-tight somehow and you're ready to go. Honestly, I would just desolder them and save some headache this way.

Are you sure? yes | no

Jesse wrote 09/03/2022 at 16:37

Thanks for the reply. I hadn't considered some of those issues before.

If I was to go with the AFBR-S4N66C013 as an alternative the spec sheets shows several more leads than the MICROFC-60035-SMT.

The spec sheets says "All cathode balls (C_1 to C_6) are connected together. All anodes (A_1 and A_2) are connected together. Unlabeled balls are floating, preferred electrical connection to cathode voltage. "

Would I only need to solder one wire to a single anode ball (ground), one wire to a cathode ball (power) and one wire to a single floating ball (signal)? Sorry for my ignorance on this.

Also, would the MICROFC-10010-SMT-TR1 be another alternative?

Thank You!

Are you sure? yes | no

NuclearPhoenix wrote 09/03/2022 at 17:32

Yes, the AFBR-S4N66C013 has a completely different package which is much harder to solder! According to the datasheet the anode must be connected to the SiPM voltage and the cathode to the signal pin. You don't need ground here. I haven't found any eval boards for this kind of SiPM, that would definitely come in handy!

I would advise against the MICROFC-10010-SMT-TR1 as the general photon detection efficiency is much smaller (and the size too of course). In addition to that its gain is also smaller by an order of magnitude. Maybe you could get the 35 µm version of the 1 mm SiPM, that might work again.

Are you sure? yes | no

Jesse wrote 09/03/2022 at 21:05

Awesome, thanks for the help. I'll let you know how it goes. I'll probably stick with the MICROFC-60035-SMT and wait for stock to come in.

Are you sure? yes | no

hathawayresearch.george wrote 08/29/2022 at 14:36

Will someone offering a complete "OEM" package including SiPM & Scint for those willing (like me) to pay but don't have the time to build?

George Hathaway (george@hathawayresearch.com)

Are you sure? yes | no

NuclearPhoenix wrote 08/30/2022 at 09:11

Hi there George, I can only speak for myself, but currently I don't have the capacity to offer complete kits. I've started with the main detector board now and if there's enough interest, I'll also offer the SiPM on its little carrier board too.

Are you sure? yes | no

hathawayresearch.george wrote 08/30/2022 at 16:26

Thanks for the reply. Hope someone might pick this (full OEM) up someday. Such a cool project.

Are you sure? yes | no

ysyangsongzz wrote 07/19/2022 at 09:44

I will try the DIY project ,I hope you provide new information.

Are you sure? yes | no

ysyangsongzz wrote 07/18/2022 at 09:47

Your answer:The energy resolution is at about 15% @ 300 keV, very highly dependent on the scintillator crystal of course and your whole SiPM/crystal assembly. In fact, I'm not even sure 15% is the best, it's just what I achieve with my simple used scintillator. I couldn't test it with Cs-137 at the nominal 600 keV yet.

My question:This resolution is a little poor. The resolution of normal Nai scintillator spectrometer can reach 7%~8%. Can the energy resolution be improved by changing Nai and increasing the number of SIPM?At present, this product cannot measure Cs137?

Are you sure? yes | no

NuclearPhoenix wrote 07/18/2022 at 15:23

Like I said, I bought my scintillator used so I don't know the energy resolution 100% for sure. You will probably have a better resolution with a brand-new crystal from a reputable manufacturer. The detector can measure Cs-137, of course! I simply haven't come around to measuring it since I don't have it at home currently ;)

In fact if you can get a great mount with the new SiPM carrier board, you will surely get an even better resolution. By the way, most of the cheaper commercial spectrometers have an energy resolution of up to 12 - 13% so that's not too far off. However, that's measured at the Cs-137 662 keV line so you can't compare it 1:1.

Are you sure? yes | no

ysyangsongzz wrote 07/18/2022 at 09:20

OK,NuclearPhoenix .I see it again.

Are you sure? yes | no

ysyangsongzz wrote 07/18/2022 at 08:29

Hello,NuclearPhoenix .Is the NaI crystal used one inch in the DIY project? SIPM is 6mm*6mm. I want to ask how SIPM and Nai are coupled to ensure the photon collection rate. THe energy resolution question in the PMs，the PMs is what?

Are you sure? yes | no

NuclearPhoenix wrote 07/18/2022 at 09:15

The coupling process is described in the build instructions and on GitHub. "PMs" are the private messages here on Hackaday, you sent me a message there.

Are you sure? yes | no

ysyangsongzz wrote 07/15/2022 at 00:36

Hello,NuclearPhoenix .How many sipms are used in this DIY projet? What is its resolution to Cs-137? Schematic v2.0 version has been released on GitHub website. When can the corresponding v2.0 PCB be released?

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NuclearPhoenix wrote 07/15/2022 at 12:05

Just one SiPM, otherwise I would have stated so in the documentation. The PCB is already released on GitHub. I already replied to your energy resolution question in the PMs.

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ysyangsongzz wrote 07/14/2022 at 02:42

Have you considered the temperature drift of SIPM？

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NuclearPhoenix wrote 07/14/2022 at 15:51

No, it's not temperature corrected since this is a DIY project designed for use in controlled environments. Of course there is some drift, but if you use it close to the nominal 25°C you will not notice it.

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Wesley Ellis wrote 05/19/2022 at 00:36

Neat project, but I think there's a typo in "a USB power cable and safe the spectra to the Pico's flash storage" where safe should be save

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NuclearPhoenix wrote 05/19/2022 at 09:17

Yes, thank you!

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yahyabangash2004 wrote 05/06/2022 at 16:06

Good initial

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All-In-One Gamma-Ray Spectrometer

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schematic.pdf

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FW 3.4.0: SH1106 support + ticker changes

Calibration for newcomers

FW 3.3.0: Ticker support

FW 3.2.1: Stability Update

FW 3.2.0: More faster = More better

Performance w/ array board

Firmware Version 3.1.0

FW 3.0.1

Kitspace Updated

Here comes 3.0!

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All-In-One Gamma-Ray Spectrometer

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