r/Radiation

Also at the German Museum in Munich. It is the Table where Otto Hahn, Lise Meitner und Fritz Straßman discovered the splitting of the Atom. What u See on the table are just examples of theire Equipment in the Kaiser-Wilhelm-Institut für Chemie in Berlin what they used to Work and at the end discover nuclear fission

Edit: I forgot Otto Hahn him self brought the stuff to the German Museum

I saw this yesterday in the German Museum in Munich. I saw this for the First Time in Real live and the box is enormous

A friend sold me his "old" radiacode for cheap and and im curious what i can do with it .

I know it uses a scintillating Sensor, unlike normal geiger counters which use a GM-tube, but what are the actual use cases for a device like this, i only own a ludlum model 2 and it is fun using it but i never owned or used a digital one.

What can i do with this?

In Germany, helicopter training flights of the german federal police are conducted to detect radioactive ground contamination. What kind of measuring instruments are used for this? Don't the detectors have to be incredibly sensitive to pick up a sufficient signal from a significant altitude (given the inverse-square law)?

Is this only for mayor accidents or also for counter-terrorism purposes?

So I finally got around to testing one of my more interesting ebay finds with my gammaspectrometer setup (GSMAX8000 & GS1515CsI(Tl) & leadcastle). It's a Varian 1B63A gas switching tube, date code says March 1975.

For those who dont know, these tubes were used in radar systems as TR (transmit-receive) switches to protect the mixer crystals from high-power radar pulses. They contain a small amount of Cobalt-60 as a radioactive source to help ionize the gas inside, which is needed for the tube to switch properly.

This particular one has "MAX 0.7 uCi" stamped on it. So I did the math for today (2026):

• 0.7 uCi = 25,900 Bq originally (1 uCi = 37,000 Bq)
• Co-60 half life is 5.27 years
• Time elapsed: 1975 to 2026 = 51 years
• Decay factor: 0.5^(51/5.27) = 0.5^9.68 ≈ 0.0012
• 25,900 × 0.0012 ≈ 31 Bq

So roughly 30 Bq left, which matches what others have calculated for these old tubes. Should be enough to see the two Co-60 gamma lines at 1173 and 1332 keV?

Result (10 hours aquisition): I cant really see them directly in the raw spectra. Only after a hard background subtraction (using my lead castle background) do I get slight bumps that might be there. Its right at the noise floor, barely above it. Kinda disappointing but I guess 30 Bq isnt much for my amateur setup. Or am I over-interpreting here? But there must be something, because I see about 7k counts more with the tube in the leadcastle/ vs without - which is about 0.2CPS (I repeated that 4 times, always the same result).

Also Im still seeing K-40 in my spectra (that 1460 keV line) which is annoying because I dont know why its still there after background subtraction (maybe drift, but I collected background and sample acquisition quite close to each other).

Anyway, cool piece of history even if the radioactivity is mostly gone now. These tubes are getting harder to find with the original Co-60 still intact. You can find quite many tubes on ebay, but most of them have been manufactured in the 50s and 60s, which means for sure "game over to any Co60 signals". So finding one from the mid70s is like a scarce find :-)

In case those two bumps are Co 60: I have another species confirmed on my radioisotope list :-) - and Co60 is very very very difficult to lay your hands on here in Europe (legally).

I love the AlphaHound visualization, but I wanted a clean 'big screen' view on my second monitor. I built a simple, local HTML dashboard that pulls the live counts directly—no heavy software, just an ambient status display for my desk while working. i used a bit of AI help to code this. You can check it out here

https://alphahounddpdash.tiiny.site/

or i can send you the html file aswell if intressed.

Edit: Updated it so it can show alphas and betas as well in different colors.

The company I work for also owns a school, the school was tossing them, and I got these with permission. I also scored some UT equipment but I won't be posting that here. I also got a few tin rad area warning signs. Those metal shims are for placing IQIs, those ones are a alloy called magnesium-thorium alloy whish is slightly hot (1.74 mRh at surface)

Howdy y'all! I got some cool stuff to share that I get to work with.

Pictured is 35 Ci of RGPu, consisting of Pu238 through Pu242. Each zircaloy triangle encapsulates powder that has an individual activity of 7 Ci, with the majority of the activity coming from Pu241 (~99%+). Thankfully, since Pu241 decays almost selectively through beta decay, there's barely any neutrons being emitted.

However, that high Pu241 activity leads to a lot of Am241. And I mean a lot.

Using a mechanically cooled HPGe, I saw around 1 kcps in the Am241 photopeak of 59.5 keV at 1m distance. Pretty wild.

Contact dose rates using an Ortec Rad Eaglet hover around 0.3 mSv/hr (all from gamma). Since the zircaloy absorbs the majority of the betas and all the alpha particles, I'd guess the unshielded dose rates to be closer to ~1 to 2 mSv/hr.

At 0.3m, the dose rate drops to around 50 uSv/hr. (Equivalent to about 2.5 chest x-rays per hour)
At 1m, it's closer to 3.8 uSv/hr. (Equivalent to a short commercial flight)
And at 2m, it's down to 1.1 uSv/hr. (3x normal background)

This just goes to show you the power of distance!

Howdy All,

Yesterday I posted several 7 Ci reactor grade plutonium sources, and today I’m coming back with some dose rate updates.

First off, the contact dose rate I mentioned yesterday was significantly lower than what I measured today. Depending on a triangle’s position, I saw as high as 2.5 mSv/hr. Absolutely wild. This is on the order of 1 CT scan (of a limb) per hour for perspective. Around a day of direct exposure at this level would exceed current annual dose limits. And it’s only gamma dose (maybe including some betas that escape the zirconium casing).

However, it’s important to take into account proper tissue weighing factors and that this dose is in the short field. Meaning the difference in hourly dose rate between the front of your body (if you were looking at the source) and your back will be significantly different. The total dose you’d actually receive would be significantly less than what’s read on the detector.

That being said, distance is your friend.

At 30mm, the dose rate drops to 167 uSv/hr. Doubling this distance a couple times, we get to 480mm, and the dose rate drops to a very manageable 3.84 uSv/hr (around 10x background levels).

While the dose doesn’t necessarily drop as 1/r^2, it’s close. I calculated the trend to be close to 1/r^1.1, which is expected given the system geometry. The detector presents a rather large solid angle to the source.

Thinking I'd get a multimeter out and probe the connections. Battery is out right now but yeah.

CDV-715

Love this so much!! I want to learn more about the particles I’m seeing

I'm not sure where to find advice so I figured this sub could help me. I've been trying to build a cloud chamber and settled on two peltier modules in series between an aluminium plate and a ventirad, with 99.8% IPA evaporated from felt which is heated up by a hot-water bottle.

I didn't check the temperature gradient but guessed it was sufficient since I could observe a nice mist, however there are no ionization traces to be found even after days of trial and error. I made sure the setup is airtight with an insulating foam tape + some additional weight on top, and I also tried using a thoriated tungsten electrode for alpha traces but to no avail (see video).

I tried changing light for contrast but this is the best I could get since this light is directional enough (the flickering is purely a camera effect, also the contrast seems worse on video than to the naked eye). I have this instability in the left part of the chamber, and it seems to originate from a particular side of the lid (if I rotate the lid the instability rotates with it). I think I have some convection currents but I don't know how to get rid of them without destroying the temperature gradient. The transparent lid roughly measures Lxlxh = 10x10x15 cm^3 , maybe I should aim for a 10x10x10 cm^3 ? I tried smaller but got a worse mist overall so I wouldn't go lower.

TLDR: I'm not really sure what the problem is, my guesses are either bad light or bad lid but in any case I don't understand why there no traces at all even with a radioactive object inside the chamber.

that is over 9000 CPS on this device

It goes nuts over my radium clock, fiestaware, uranium ore, and fossils, so I know it works. I worked with cesium-138, Fe-59, tritium, carbon-14 in the past, so I’m not totally ignorant, but new to sampling and Geiger counters in general. Thanks!

I bought this Romanian AD-111 at the flea market the other day. It seems to be a copy of the DP-5, the scale is in Russian and has Made in USSR written on it, the buttons on the outside are in Romanian. The check source has already been removed prior to me buying it, but my main concern is the fluorescent scale, I'm pretty sure the DP-5 doesn't have radioactive paint but I've read that this one has paint made of tritium or radium. I don't have a geiger counter to check it for sure, so I hope someone knows a bit more about it. If it does have radioactive paint, is it safe to keep in my room or do I need to store it somewhere else?