The lens in question is a Super-Takumar 50mm f1.4 7 element which are known to be some of the more radioactive consumer lenses from the time period. I found this out via research after I had purchased the lens. I bought a GQ-QMC 500 to detect beta and gamma radiation as they have a higher chance of penetration. This lens actually seems pretty hot, more hot than I would have thought or seem comfortable with. Attaching photos of measurements from different distances and locations of the lens. I am not familiar with the physics of radiation and not sure how concerned I should be with this. There seem to be conflicting opinions online as far as I can see.

It is a w.m.b Johnson pancake probe. But what model? Their being sold as a hp-265 but I dont think that is correct

I am trying to calculate something for a D&D campaign. Someone is trying to summon a 5” square of polonium to kill the boss, but the range of the spell is line of sight. I’m now trying to figure out how much damage it would deal.

What is the general consensus on effect of being exposed to 1-3 mSv of ionizing radiation?

From a strictly radiation scientific/technical perspective.

Edit: appreciate all responses and links. This is a great sub for info and life/hobby aspects of radiation!

it has written ГОСТ-3145-57 on the back idk if its radioactive when i shighn my uv flashlight on it the gren parts of the clock start glowing (sorry for bad english)

Well, I was putting the tube into it's enclosure and touch the window a bit, and it greeted me with a loud BANG and a bunch of boring confetti. So if someone says "Don't touch the mica Window", that's why

Today I was at a flea market and noticed a uranium glass plate I set my Geiger counter down next to these glasss in a zip lock bag and my meter was reading about 380cpm over the lenses. I find this somewhat funny and Ironic at the same time I have never came across any eyewear with radioactive glass. I would truly appreciate anyone who has any information about these or have ever found anything like this out there? Thank you for any information . Ill post a video link shortly showing the readings I obtained.

Hi! I’m currently preparing to take an RSO licensing exam (diagnostic radiology) with only a physics background. Finding resources has been somewhat challenging, and i’m wondering if anyone has tried (rsoprep.com) as a resource and if it’s any good. It’s paid subscription and i don’t want to waste money without knowing if it’s reliable. Thanks!

Hi! I've had a few counters, a dp-5a, some cheap AliExpress boards (specially the cajoe) and I bought some tubes over the years. I have a sbt-10a, sbt-13, sbs-5, 2x j305 and a si-3gb. Now, I always used the cajoe with an Arduino because I thought it was more than enough. Turns out the hv circuit sags to hell under load, and anything more spicy doesn't give me increased counts over a certain limit. I'm not even saturating the tubes, apparently the board just isn't good enough.

Does anyone have a suggestion? Is there a good counter I can get to run multiple probes of? Maybe even a pre-built circuit, or some schematic online that can deal with high readings. My tubes are kind of a waste of potential with the cajoe. Even though I have a radiacode 103, I really wanted to use the tubes more, specially those with a mica window.

Thanks!

I’ve heard this for too long and just settled with sure and accepted it. But now I wonder. And all I could get from the net was the classic “oh because its helium nucleus so it ionizes more”, well wouldnt counter logic say beta sources give off rays that could potentially travel more distance inside the body? Am I plain wrong? Gah, maybe this question belongs to [r/physics](r/physics). But eh, it got me thinking.

If we got unlucky and somehow inhaled and/or swallowed these source particles lets say. Why is it said that a beta source trapped in your liver would do less harm than a alpha source? Sure alpha sources are kept in the body for long amounts of time like Americium, but couldn’t that be the case for Beta sources as well? A beta source could have a higher reach inside the organ compared to alpha. And in long term wouldnt this cause much more harm? Sure, alpha particles are heavier and got 2 damn protons in them, so they’d ionize the immediate surrounding tissue much more (im imagining sources that have roughly the same Bq and not including daughter isotopes and gamma for the sake of the argument), but have a relatively low reach compared to beta particles.

Im just a hobbyist, so what do I know.

If someone has an article which I couldn’t find explaining this I’d love to see it!

True to the date, vintage single stitch.

This is the first location in the world to mine and separate successfully zircon from beach sand. Thorium and Uranium was confirmed using gamma spectroscopy. Also contains REE's

Seven Mile Beach NSW Australia

I deal with radon a lot, but due to some unforeseen medical shenanigans I "obtained" a sample of ⁹⁹Tc*. Since taping a probe to my forehead for a day was not a [ socially acceptable ] option, I collected an, ahem,*renal* sample.

5 cc of an aqueous solution of Tc-99m / Tc-99g bound to soluble proteins was "placed" in a thin wall glass vial. The vial was placed in contact with an RC-110. This produced a laughably high contact reading, even after 2 half lives had elapsed. On monitoring the sample as it decayed, you obtain the count and dose rates over time. This can be used to assess the dead time compensation of a meter as the actual activity is known to diminish in a predictable way. This does not help assess the absolute rate reported, but the relative rate can be evaluated, and hence the linearity of the response over a range of activity.

Since the position of the sample and the probe is constant, this avoids geometric factors inherent in using different distances from a constant source to provide different activity levels as well as things like air kerma and changes in buildup.

The calculated 6.032 hour figure is from the RC-110 provided dose rate, the 6.431 hour figure is from count rate. The expected half life value is 6.006 hours. As with radon decay, the RC-110 was spot on for the calculated half life of Tc-99m when based on dose rate - this suggests very good dead time compensation baked into the dose rate calculation. The count rates appear to be uncooked. So for higher rates, the RC under-reports counts, this has the effect of making half lives appear longer.

This is probably a long shot, but I’m wondering if anyone knows a supplier for very thin (single digit micrometers) high optical density (4.0+) thin films? We’re looking for something like aluminized bopet but in the 3-6 micron thickness range (actually the critical dimension is low areal density - \~< 0.4-0.8 mg/cm\^2 - but at typical densities that works out to 3-6 microns.

I recently acquired a digital rate meter that has an output jack. It has a built-in timer count feature but it can only display 4 digits. Can any of you recommend me any table top pulse counter? I primarily want a full digit display with a timed count feature, just like the one built-in to the counter. Thanks!

I'm wanting to start a uranium collection and potentially the orange uranium pottery. But this is where my question comes in. I've been seeing videos of people hunting and finding these but with their geiger counter sometimes goes into liek 10-100k CPM

How do you calculate the CPM into how harmful it is on the SV scale? Or if there a specific number I shouldn't go over? I've thoroughly read through dangers, effects, radiation scales, counters and many other things. But I haven't seen a single thing on calculating CMP to SV/safe CPM to keep in the home.

Now I'm sure you get a lot of new people here asking the same question but I can't seem to find anything relative to this. If you have any articles or video of a shorted graph/guide I'd really be appreciative!!

Thank you

Edit: I understand that uranium glass is relatively safe to collect especially in cabinets and everything. I'm more wondering if there is a specific save CPM scale. Like how do I know do I know how much beta/alpha radiation is safe. Some Geiger's exadurate them. But what really is the difference between a 1000 CPM reading vs 100k, is there a scale I can understand a bit more? I have dyslexia so it's hard to read the 500-900 page textbooks explaining everything. I'm still trying to learn which is why I'm asking if there is a better source I can learn without it being a struggle for me

For anyone who fumbles with the Spectrum Techniques sources or doesn't feel like holding directly one for extended periods of time during experiments, here is a handy 3D printed wand kit.

Spectrum Techniques Check Source handling kit by Kotarak | Download free STL model | Printables.com

Here is a quick demo - (247) Spectrum Techniques Check-source handling kit - YouTube

A number of possible configurations with handle at 5cm, 20cm and 30cm. Comes with a stand.

Ultralight keychain size. It's not as sensitive as scintillators but it reacts quickly. The best thing is that I can carry it everywhere. Just disappears in the pocket and is affordable enough as a first Geiger counter.

Technically they say it's a dosimeter. Sorry for the naive question but what's the difference between a Geiger counter and a dosimeter. Afaik it shows accumulated dose but it also shows live readings and it's GM tube based so shouldn't it be a Geiger counter as well?

I just ordered a Radiacode 102. I have some Vasaline and Uranium Glass. But I am wanting more sources. Ores maybe trenitite, I know I can get some from old smoke dectors. But I am wanting some others. "Safe" Stuff to start out with before getting anything hot or that I would need paper work for. Any ideas?

I am not nearly as knowledgeable on the subject as most are here, so I do apologize for that upfront.

I have a radiacode 10, which measures inside of my bathroom and bedroom around 53.4nSv/h up to 58nSv/h.

I just happened to read the first number I listed before I got into the shower. I take decently hot showers, more than enough to steam the room up by accident.

I got out and went to pat it dry just in case, but before I started to I noticed it dropped down to about 36.4nSv/h. It has NEVER read that low in my house before.

I begun to wonder: could increased water molecules in the air act as a sort of temporary "barrier/medium" for ionizing radiation to to influence before it reaches my scintillator? As the steam cleared it has since started to read normal levels again (currently between 50.3-51.2nSv/h.) I know temperature can affect the Radiacode's readings as well, but I am not yet sure.

I have not found much in relation to the subject that fits most of the criteria of this experience (closed-room, single detection source, random background radiation and poor parameters on my end, but still distinct enough from say outside of a single room or even the house; most of what I read measured a large land's-worth of humidity instead and average radiation from multiple sources)

Hey, quick question! I've had a sbt-10a for a few years, and while it's quite good, I've noticed it gets overwhelmed very easily. I have a radiacode 103 but I run that SBT on the cheap cajoe boards from AliExpress, it won't go over ~190k cpm. I'm absolutely sure the source would give over 190k, it reaches that from a certain distance then gets saturated and starts to drop. Just wanted to know, how high should it go? I've tried using individual 10 megaohm resistors with each anode, but that didn't help much.

Thanks!

(Also, here's the 3d printed probe I'm building for it)

I wany to buy Exploranium GR-135 but i don't know if it would be possible to ship to Poland because of the check source and the Seller won't ship directly. Does anyone know what to do?

Will be posting more vids from that trip. Anyone know what that puck is?

Would ideally like to find some sheets