Science, Engineering, Electronics, Amateur Radio, Nuclear Physics
Gamma Dog Maxi was built with basically the same 3D Printed housing that Charles designed, but extended to fit a large 63x63mm NaI(Tl) detector. It is much closer in size to my main Gamma Dog line with 4" diameter housing and since I was reusing the old Gen3 electronics, this unit received the electronics package with serial number "AS001" Beyond the larger housing size and construction is…
Finally found some time to work again on the Gamma Dog project. I had 3 GD electronics modules from the Gen 3 run and a bunch of 38B57 detectors laying around so I decided to turn them into actual units and add some improvements to the firmware. New Firmware release - Current version is 5.9. These are just some of the improvements: - completely new sound library with harmonic suppression and…
One of Gamma Dog's unique features is the continuously variable tone representing the detected count rate by changing its frequency. The approach is fairly straight forward - the detected count rate in CPS (Counts-per-second) coming out of the detector and into the MCU is converted into an audio tone with the same frequency - i.e. 200 CPS will produce 200Hz tone and 1000 CPS will produce 1 kHz…
I was putting together SOTA/POTA portable antenna kit for my son, utilizing EFHW and EFRW antennas and I needed a Common-Mode Current Choke - something not very large and efficient that he can eventually use from QRP to 100W on 40m to 6m. This is just a quick, easy, 15 min. build, and the result is an excellent and pretty efficient CMC Choke (see the measurements below) for only $25, that one can…
Finally, I got around to make an enclosure for the Moxtek X-Ray Tube Controller with a proper control panel. The complete "X-Ray Tube Commander 2000" Controller in all of its glory. This enclosure might be further improved with an angled front panel at some point if I get too bored but for now it serves the purpose. The faceplate text is currently done "quick-n-dirty" style with a Label Maker but…
Elecraft KX3 is a fantastic portable transceiver but one thing I thought could be improved on is the front panel presentation by using a better stand to the stock, foldable legs. The built-in foldable legs of the radio are a bit annoying to deal with as they require the user to manipulate the thumbscrews used also for holding the radio together. Because the thumb screws are opposing, this needs to…
Today, 13 years after this post , FCC issued my son's first callsign - KC1TVB. Congratulations to Vichren for passing the exam and joining the lines of the Amateur Radio Operators! Update: Vichren applied for and got a vanity callsign - N1VAS . His very first DX on HF was a KH6 station in Hawaii on 10 meters using only 10W from an Elecraft KX3 into a portable Buddipole dipole, slicing thru a…
One of the main features of the Gamma Dog project is the unique Squelch System controlling the audio output. Anyone familiar with two-way radios will be familiar with the Squelch System used in FM Hand-Held Transceivers. In a nutshell, Gamma Dog's Squelch System mutes the audio output of the instrument if the currently detected rate is at or around the natural radiation background level. If the…
When it comes to those big, beige, analog metering systems, heavy metal and clunky radiation detection istruments from the 80s... I am a huge fan of ... not Ludlum Model X but the Eberline ASP-1. I have 3 such units and they are really cool and versatile "blast from the past"! For anyone interested I made a brief review and comparison between Ludlum Model 3 and ASP-1 . Eberline ASP-1 was and still…
I finished the design of PCB v4.0 for the Gamma Dog and OSH Park service came through again with excellent manufacturing quality boards. The improvements in the schematics and layout are not huge but this version incorporates the progress in the development, which continued after PCB v3.0. Gamma Dog Main PCB v4.0 Bottom layer with a Marie Curie quote. Changes from PCB version 3.0: Changed the…
Commercial scintillating detectors are usuallu very expensive - hundreds, often thousands of dollars for a good size NaI(Tl) detector. Such detectors are not always affordable for amateurs, even on the secondhand market but for many applications they are the optimal, and sometimes the only solution. There is a hidden, and often overlooked and underestimated gem though, made by a leading in the…
This scintillator build is not much different than the others except for using a CsI(Na) crystal and 2" / 51mm PMT. I understand that people use these posts as a guide when building their own scintillators so I decided to document it as it might provide additional information, which I might have missed in previous posts. Using Gamma Spectacular PCB for R6231. This PCB is designed for both, single…
My DIY XRF setup is finally complete - it is comprised of an Amptek X-123 detector using the proprietary Amptek 25 mm 2 / 500 μm Si-PIN X-Ray detector element (model FSJ32MD-G3SP), Amptek Pre-Amplifier and DP5 DPP /MCA. Details about the detector are in THIS post . On the exciter side, in the past, I have used X-Rays from an Am-241 source (59.54keV). Unfortunately, there is no exempt quantity or a…
A follow up on this post this post I needed controller for the Magnum series 50kV / 10W MOXTEK X-Ray source and as it turns out the FTC-200 controller, once sold by MOXTEK is no longer available - it was discontinued due components availability and the Moxtek sales engineer told me - "We expect customers to develop their own solutions." This was not a big deal - their FTC-200 controller has very…
I am working on a new XRF Exciter source, employing a pretty cool miniature, ceramic, 10W X-Ray tube with Tungsten transmission target by Moxtek (MAGNUM series). This source will deliver an immensely higher X-Ray flux compared to the Am-241 source I've been using, thus cutting down on the integration time during XRF analysis and bringing out peaks hiding in the noise. The Moxtek X-Ray tube comes…
One thing that was really bugging me with the Gamma Dog circuit was the original analog audio volume adjustment. The MCU swings a digital output pin, driving the amplifier input between 0V and 3.3V. This output is connected directly to a linear (class D) 1W audio amplifier which employs a tiny trimmer-potentiometer for gain adjustment. To adjust the audio level in the field, first I have to remove…
So how does the Gamma Dog perform? The short answer is - fantastic! I am really happy with the performance. Charles and I have been testing our instruments inside and out and they work great - sensitivity is excellent so as the ease of use. The operation is a complete joy and a fun user experience just to go out in the field and hunt for radioactive minerals with the Gamma Dog. We seem to have…
The idea behind Gamma Dog EXP is to have a self-contained electronics module which I can connect to various external probes. This allows a certain level of flexibility - detectors using smaller crystal can be attached to a wand and used in the "Metal Detector" style setup, sweeping larger areas much faster or an alpha scintillator can be connected to check for contamination. I also use this setup…
For my Gamma Dog EXP (External Probe) I wanted to build small and lightweight detector to be mounted on a "Metal Detector style wand". The weight is important as the detector is basically on the end of a long pole (which is great for covering larger area in a single sweep) and all of the implications from momentum and inertia of a large mass are present. The pole becomes a lever in your hand and…
A friend of mine and an avid REE mineral collector Charles Young designed some time ago an instrument intended specifically for finding radioactive rocks "in the wild". The design evolved from his initial concept to become a pretty clever and viable solution but at the time it was using audible clicks, very similar to a Geiger Counter. Charles and I have been talking for a while, exchanging…
In the world of scintillators, larger crystals means more sensitivity - when you have a bigger volume of scintillating material, it can capture more photon interactions and will produce more pulses. High-energy photons sometime can pass thru a crystal without interacting with it and more material in the way means higher chance for interaction. I've been doing some radioactive rockhounding using a…
I obtained 2 fragments of the Sericho Pallasite Meteorite, "discovered" in Habaswein, Eastern Kenya in 2016. The meteorite has been known to local populations for many years but it wasn't until 2016 when the meteorite was officially classified as such. This was a huge meteorite - so far 2.8t were recovered. A highly sculpted complete fragment of the Sericho meteorite. This specimen exhibits the…
The exciter is the second main component of an XRF setup - this is the source of the primary X-Rays. Two type of Exciters are generally used - X-Ray tube or Radioactive Isotope. X-Ray tubes Pros: - provide high-intensity beam - low limit of element detection - easy on/off capabilities - fast integration times - fairly clean and uniform spectrum - very small spot of irradiation / sampling Cons: -…
Amptek ( Amptek ) is one of the leading companies for Space instrumentation, experimental and research XRF equipment. They have a fantastic line of products called X-123 Spectrometer - (1) detector element and preamplifier, (2) Digital Pulse Processor and MCA and (3) Power supply. It is all-in-one device which only requires an external power and connection to a computer. The PC software by Amptek…
What is XRF? XRF stands for "X-Ray Fluorescence" and there are two main types: Energy Dispersive XRF and Wavelength Dispersive XRF. I'll focus on the Energy Dispersive, Direct Excitation (2D) Method as this is what I use. EDXRF is a Non-Destructive method for material analysis, used to determine the Elemental composition of a material or a chemical compound. It is an extremely useful tool to…