• Radioactive items

Exploring Naturally Radioactive Elements – Lutetium 176

Welcome back my fellow radiation nerds!

When we think of naturally occurring radioactive elements we mainly think of Uranium and Thorium and maybe sometimes Potassium. While those elements are the most common ones, there are many others that also have naturally radioactive isotopes. However, most of them have very long half-lives making them extremely hard to detect, especially without specialised equipment, but there are a few that can be measured with a sensitive Geiger Counter or Scintillation detector. One of them is Lutetium with its radioactive isotope of Lutetium 176.

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The Discovery

Lutetium has been discovered independently by three scientists in the year 1907, a French scientist George Urbain, Austrian mineralogist Carl Auer von Welsbach, which you might also know as the inventor of Thoriated gas mantles, and American chemist Charles James. After years of dispute, George Urbain has been named by the scientific community as the discoverer of the new element and he named it Lutetium after Lutetia, the ancient Roman name for the city of Paris.

Properties of Lutetium

Lutetium is a rare earth element with an atomic number of 71. It is the last element in the Lanthanide series and it shares many of the chemical properties with other elements in the group. In nature, it has only 2 isotopes, a stable Lutetium 175 (97.4%) and a radioactive Lutetium 176 (2.60%).

Lutetium 176 undergoes a beta decay with an average energy of 182 keV, turning into Hafnium 176 with a half-life of 37.8 Billion (3.78e10) years, and in the process it also emits gamma rays at 88, 202 and 307 keV. What is Interesting about Lutetium 176 is that the both gamma rays of 202 and 307 keV are emitted in coincidence with each other, forming summing peak at 509keV

Uses of Lutetium

Today Lutetium doesn’t see much use due to its difficult production and very high costs but it can be found in some specialised fields. One of its main uses is in the production of scintillation crystals which are used in positron emission tomography (PET) scans.

It can also be found in some alloys like in the case of like LuAG where it improves the overall durability and heat resistance of the material.

And thanks to its long half-life, Lutetium 176 can be used for Lutetium-hafnium dating of meteorites.

My samples & their radioactivity

At the moment, I have two types of Lutetium samples. The first one is a form of LYSO scintillation crystals which I got from a friend of mine (thanks James!), I have linked his eBay store in the description below in case you want to grab one for yourself.

James Ebay Store

When measured with SE International Ranger which uses a LND7317 Pancake type tube, I got from a single crystal 73 CPM, only 30 CPM over the background radiation. When measured with my RAYSID I got an increase of 15 CPS in the activity which is more than enough to build a gamma spectrum, however a good lead castle to minimise background radiation is definitely a good idea.

As mentioned before, these crystals are used in positron emission tomography (PET) and when exposed to radiation they glow in a light blue colour.

My second sample is a metal coin made out of pure Lutetium metal which measures 24.26 mm x 1.75 mm and weighs about 8.43g, this means it contains around 0.218g of pure Lu176 that has activity of approximately ~432 Bq. Compared to the LYSO crystal, the activity is a bit higher and reads on my Ranger 160 CPM above background and 55 CPS on my RAYSID.

Since the coin is made of pure metal, it is much denser than the LYSO crystal and some of the activity gets self shielded which results in the readings being a big lower than expected.

Since I use it as my main Lu-176 source for gamma spectroscopy, I decided to put it in a 1″ plastic disk with a label stylised a bit after other professional calibration sources. While it might be a bit goofy or silly to some, I do enjoy a consistent look of my sources and I’m very happy with the results.

Isotope Lutetium 177

In nuclear medicine, a synthetic isotope of Lutetium, Lu-177 is used in targeted cancer therapy. It is produced by neutron irradiation of Lu176 and it decays through a beta emission into Hafnium 177 with a half-life of 6.65 days and it emits two gamma rays at 113 keV and 208 keV.

A good friend of mine works in a nuclear lab and recently they received a fresh batch of Lu177 for their experiments and he was kind enough to make some videos showcasing the samples, testing them against some of his meters and take a gamma spectrum of them. Big Thanks for the help!

Originally this vial contained 3.2GBq of Lu-177 in form of Lutetium Chloride solution, however most of it has been already removed and now there are only traces of Lu-177 left. Despite that, the vial still read pretty high on the RadEye B20 with over 60k CPM and registered 760uSv/h on the RAYSID.

Summary

Exploring the radioactivity and the history of Lutetium and its isotopes was definitely a great experience and I have learned a lot about it. I want to hear from you, did you know about the natural radioactivity of Lutetium and do you have any samples of it? What other radioactive elements should I cover next? Let me know in the comments below!

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Introduction

Today I want to show you an item that you can find in a hardware store and it is radioactive. Let’s take a closer look at the thoriated Tungsten electrodes!

Main information

There are three types of thoriated Tungsten electrodes with the only difference being the amount of Thorium in them. Yellow ones contain around 1% of Thorium, red contain 2% and orange contain 4%. Even though orange ones contain the highest amount of Thorium, they are actually not much more radioactive than the red ones which are the most common. Tungsten electrodes come in different sizes with the bigger ones being slightly more active. Personally, I decided to go with 3.2mm x 175mm but smaller should also work fine.

Since the label on the box clearly states that these electrodes contain Thorium, I didn’t expected the gamma spectroscopy to show anything intresting but to my suprise, it did!

The main two differences between the spectrum of Tungsten electrodes and the spectrum of Thorium gas mantle are the peak at 511 keV and the peak 583 keV. Let’s start with the peak at 511 keV. It is referred to as annihilation peak and it is caused by the annihilation of a positron by its interaction with an electron. This event can occur more often in Tungsten electrodes because of their density. The peak at 583 keV is caused by Thallium 208. When Thorium decays, it emits Radon 220 which is a gas and it escapes into the air but in the case of the Tungsten electrodes, it is trapped by dense Tungsten which results in the accumulation of Radon decay products including Thallium 208.

Safety

These electrodes are often used as a check source because of how easy to find they are and their small activity which makes them relatively safe. That being said, when used for their original purpose, the dust generated by sharpening them could cause health problems in the long run if inhaled.

Fake Tungsten Electrodes

When buying these electrodes, make sure to buy branded ones because unfortunately, unbranded ones are often fake and they do not contain Thorium. I made this mistake twice and both times I received fake electrodes that weren’t radioactive.

Today I want to show you an element that made the use of radium 226 in paint absolute! Let’s take a closer look at Hydrogen 3 or better known as Tritium!

Tritium is a radioactive isotope of Hydrogen with 2 neutrons which makes it unstable and thus radioactive. It was first discovered in 1934 by a group of three scientists, Ernest Rutherford, Mark Oliphant and Paul Harteck who have bombarded deuterium with high-energy deuterons which resulted in the creation of Tritium.

Today, Tritium is most often produced in nuclear reactors by neutron activation of Lithium-6. As a result, Lithium turns into Helium and Tritium

Tritium has a half-life of 12.32 years and it decays by beta radiation (5.7keV) and in the process, it also releases a gamma-ray (18.6keV). Since the energy of both beta and gamma radiation is so low, tritium can be safely used in consumer products.

Radiation coming from the Tritium marker isn’t directly caused by the Tritium itself. The beta particles don’t have enough energy to pass through the plastic and are stoped by it. This however causes Bremsstrahlung (X-Rays) which is then detected by the Geiger counter.

Until the 1960s, many watch manufactures used Radium paint in order to make the dials glow in the dark. However, Radium 226 is very dangerous and because of this it was banned and was replaced by Tritium which has similar radio-luminescence properties but is much safer to use.

The most common use for Tritium is in the production of radio-luminescent markers that are used in watches, gun sights. and emergency exit signs. The radio-luminescence is achieved by coating the Tritium vial with a layer of phosphor from the inside. When beta particles hit phosphor, they cause it to fluoresce releasing visible light.

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Since Tritium has a half-life of 12.32 years, these markers will remain glowing for over 10 years depending on how much tritium there is in them.

Tritium can also be used as a nuclear battery generating electricity by converting energy from beta radiation. Many scientists claim that this technology is the future for deep space exploration where sunlight is too weak to generate enough electricity to power a spacecraft.

The MARS 2020 Perseverance rover already runs on a similar kind of battery which uses Plutonium 238 and I am sure that we will see more nuclear batteries in the future!

On the 26th of April, 1986, reactor number 4 at Chernobyl Nuclear Power Plant exploded. As a result, a large amount of radioactive isotopes was released into the environment contaminating most of eastern Europe.

Today, 35 years later, most radioactive isotopes with short half-life have decayed with only 6 isotopes remaining in significant amounts from which Caesium 137 and Strontium 90 make the top of the list.

Recently, my good friend was in Belarus and during his trip, he collected some local mushrooms.

Why do I bring this up? Because mushrooms, particularly bay boletes, accumulate heavy metals. This means that if they grew in an area contaminated by radioactive fallout then there should be a detectible amount of Caesium 137 in them.

When measured with Ludlum Model 3 Survey Meter with a Johnson Pancake probe, the reading was around 150CPM which is over 3x the normal background radiation.

In order to make sure that the activity coming from these mushrooms is caused by Chernobyl fallout, I did a Gamma spectroscopy using RAYSID gamma spectrometer.

After a few minutes, a narrow peak started to form at 662keV, which is very characteristic for Caesium 137 which means that these mushrooms are contaminated by nuclear fallout from Chernobyl.

Since I am not an expert, I can not tell you whether or not eating such mushrooms is safe but if you ask me, I do prefer non-radioactive ones!

Hi, I have finally received my Quantum Scalar Energy pendant. Inside the box there was a card of authenticity and of course, the medalion which will be the main focus of this post.

The pendant is made from lava stone which has a really nice mat-black colour. There is also a rubber ring around it for additional protection.

What I did find interesting, is the fact that this medalion appeared to be radioactive, but why?

In order to find out, I used RAYSID gamma spectrometer for isotope identification. Here is spectrum after 4h and 15 minutes. As we can see, RaysID automatcly identified different energy peaks.

Here is the same spectrum but with my annotations. All peaks detected by RaysID seem to be within 1% error range. Very impressive considering RAYSID size. 

The peak on the left, at 78 kev comes from X-ray flourence. There are two peaks from Actinium 228 at 129 kev and 338 kev. The peak in the middle at 238kev is from Lead 212 and the peak at 583 kev from Thallium 208. Unfortunately I wasn’t able to identify peaks at 43 kev and 682 kev.

The isotopes detected are daughters of Thorium 232 and as we can see RAYSID already informs us about possible Thorium content. 

Conclusion: Traces of thorium can be found in lava which can make it slightly radioactive.