I recomend using soviet B1-0.1/30 tube for generating x-rays. Positive High Voltage to anode, and ground to pin 2. It is not connected to filament, but to metal disc inside, which can be used as a electron target. Voltage should be more than 40kV. It is able to generate 2500uSv/h.
Beryllium oxide hasn't been used in consumer microwave magnetrons for a long time. Its properties aren't needed at those power levels and it's expensive. If in doubt, measure the insulator's density. Beryllium oxide is about 3g/cm³, Aluminium oxide (the material that's usually used) is 4g/cm³. Unless you grind it to dust, Beryllium oxide isn't an issue anyway.
I could only make so much soft xrays with my rectifier tube. They are awful xray tubes. I burned mine up. I can still use a neon transformer and it works cold and heats up quickly. Idk what happens if i let the cup glow red but i don’t want to completely destroy the tube
Impressive for such a simple setup. Im guessing the spectrum shown is for Ra-226 oe uranium ore. It's a shame that the Pb-214 peaks aren't as defined, but still cool. The peak at 609keV is looking good however.
Well...I bought 3 of this PMTs and any of them is working. 😢...I feed it with 800V taken from a cheap clasic Marx generator power supply that can deliver 800V at 0.8mA (more than enough) using about 15V. I filter the high voltage with 4 capacitors of 10nf and 4 20kohm resistors. That leaves some ripple maybe in the 10v range over the 800V high voltage. And that''s all i see in the output at pin 9 ( white cable). No jumps or signal when i put a thorium welding rod or uranium mineral near the pmt. No matter if i take the signal through a cap or resistor. The pmt uses the 330kohm resistors recomended in datasheet.Tested with 10Mohm at first try i see no difference. In this video, ripple must be much bigger and it seems it has no influence, so i think the pmts are dead.I have checked and rechecked voltages at each dynode and connections and it should work!!...I don't know what more could i check.
You need a scintillator like NaI(th) or CsI(Th) coupled to the PMT. PMT alone will not detect gamma radiations (well perhaps at something like 0.00001%). If you want to test your PMT tube, than use a foil over the PMT with a pin hole, and use a LED in a dark box to see if the PMT output produces anything. Sorry if have a Scintillator coupled to the PMT (I cannot gauge from your comment).
One puzzle about the schematic: don't you need constant, fixed DC voltages on the photocathode and all the dynodes to get any decent energy resolution for your spectrum? I see the HV diode D3 to turn the HV AC voltage from T1 || C6 into DC, but I don't see any capacitors on the DC side of the diode, except for intrinsic diode capacitance and stray circuit capacitance, which I would guess is maybe just a few pF? Given that diode is not perfect- there will be some leakage, also there is some variable photocurrent dependent on gamma activity, and there is always 84.7 megohms of bias resistor loading, I would expect there to be significant voltage ripple. But apparently that bias stability is good enough, in this case? What is the actual HV bias voltage in operation?
OK, at 1:40 I see a pair of blue ceramic HV capacitors in parallel connected to the white wire coming from the large rectangular 20 kV diode, while the transformer connects to the other terminal on the diode, through a black wire. From those capacitors, there are red and white wires going to the board holding the bias chain resistors and PMT assy. So the possibility exists that the schematic shown at 6:53 showing no capacitor on the DC side of the diode, does not precisely represent the actual build.
Thanks for showing schematic. I think I have the same small PMT + scintillator off ebay, couldn't resist for the price. It's got a bunch of short colored wires where it was hacked out of some other assembly. How do you tell which wire is which?
Good video! I'm looking forward to build one of this. I'm curious about what this would show, if you leave this running several hours ( is that posible?) with a sample of common sand , rocks or even concrete .... Would it detect traces of tiny quantities of radiactive isotopes ?
Respect for the quest for knowledge. You have however just the request knowledge to be self harmful. The flyback transformer will IMHO develop hot 🔥 spots and eventually fry. That aside watch out for soft X-rays when you are hooking this "thing" to diode tubes. At least the microwave magnetron did that for you with its metal case. A remote control switch IMHO would wise. Leave the room before your X-ray experiments. Inverse square ⬛ of the distance, if you can't be bothered with shields 😮 Do some more research and reading before launching into stuff that you seem to IMHO appear to barely understand all the risks involved to yourself...
It a CsI(Tl) Crystal, Volume ~5cm3, already coupled to the Mini-PMT. The shown complete unit comes out of the "Radiation Pager STE mini" (google for it).
Thanks man. I haven't been doing many electrical/physics videos lately bc I'm going through some severe mental health struggles. I really wish I could, but honestly I'm just not well rn. Doesn't stop me from engaging with nature though lol
@@spectrofreak9988don't worry, you don't need to rush things, upload what makes you happy or take a break from youtube if that is what you need, what matters is your health, not what your subscribers think. I hope you get better soon, i know how complicated mental health can be, don't feel forced to upload videos if you are not well.
Some people shouldn't mess with stuff they don't know too much about. Its a "Magnatron" a hint is in the wording, it neads it's ring magnets to operate, and I see here that you have removed them. Go back and read about how a manetron works before making embarrassing video's. Also the magnetron you have there puts out microwaves, not Xrays ! X-rays are much higher frequency than the 2450 Mhz your magnetron would have put out had you not removed it's magnets.😢
Correct me. If i am wromg, but he removed the magnets precisely to stop it from producing microwaves and make it prodice x rays instead, the electrons go now in a straight line instead of in a circle and that is why this works, if they were really microwaves the GM wouldn't have detected them. Again, i am not 100% sure of what i am saying, but i have studied the way both x ray tubes and magnetrons work.
Wow, you have completely embarrassed yourself. First of all, it's spelled "magnetron". You don't seem to understand physics very well. I removed the ring magnets specifically to prevent the cyclic electron flow that leads to microwave production at high DC voltages. Had you watched the video you would know that I wasn't trying to produce microwaves. With the ring magnets removed, the electrons are accelerated along a linear path and impact the copper anode block at a near perpendicular angle to the surface, resulting in their kinetic energy being converted into x-rays instead of microwaves like in normal operation. Also I'm running this at a continuous potential of 20,000 volts instead of the normal pulsed 4,000 volts, which is enough potential to generate soft x-rays. Hence why my Geiger counter detected ionization radiation. You need to read up on physics before spewing this kind of absurdity online.
@@ElPsyCongroo. You are 100% correct. I have also studied x-ray tubes and magnetrons as part of my bachelor's degree and anyone who knows about that kind of physics (unlike the guy we're responding to) can recognize why this experiment has nothing to do with microwaves.
I can try but I honestly haven't had very much success with Tesla coils. My designs have definitely gotten up into the 100 kV range but nowhere near what a lot of people's Tesla coils can pull off. I'll still give advice if you need it though!
What are you talking about? Complete what? This video was ONLY meant to demonstrate that magnetrons can generate x-rays. The flux is too low to use in an x-ray machine so what more do you want to see? You know you could have asked politely for more details instead of being so rude about it.
