• Radiation Detectors

FS5000 – Is This The Ultimate Cheap Geiger Counter?

Welcome back my fellow radiation nerds! Today we are taking a closer look at the FS5000 meter and whether it is the ultimate budget Geiger counter!

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For a very long time I had a serious problem with answering one of the most common question in the field of amateur nuclear physics: “Which cheap geiger counter, would I recommend?”.

On one hand, there are plenty of cheap Chinese meters but in most cases they are honestly of very low quality. They suffer from low measuring range, slow averaging time and bad GM tubes that are not sensitive and can be prone to UV pollution.

On the other hand, there are professional devices such the SE International Radiation Alert Ranger which are absolutely fantastic, but they cost almost 10x what the cheap Chinese meters do and they are hard to recommend to someone who is just starting out, even if these meters are definitely worth their price.

So the question is: is there a budget friendly meter that can be bough brand new and that performs decently? Well, the Bosean FS5000 might be just the right answer!

FS5000 – Overview

The FS5000 is very budget friendly geiger counter produced by Bosean. While they are available on Amazon for around 70-80 Euro, I would recommend picking one up from the official Bosean AliExpress store site as they are a bit cheaper there, usually costing around 50 Euro and the only big downside is that delivery will take a few day longer.

Link to the Bosean AliExpress store: CLICK HERE

The meter has a very simple design which I really like and unlike some other cheap meters, the FS5000 doesn’t look cheesy or anything like that – it feels like a proper measuring device. The body is made out plastic which is pretty decent but I would still avoid dropping it and handle it with care as it doesn’t come with any type of carry case.

The user interface is pretty intuitive and the menus are simple to navigate. The measurements are displayed on a large screen which is decently bright to be used even in bright daylight. There is also a speaker with audible clicking sound which a great bonus but it isn’t very loud and can be hard to hear in some noisy environments and the LED on the top of the meter only flashes when the alarm gets triggered.

The device runs an internal rechargeable battery which should last for about 5 days according to the manufacturer. While battery life is pretty good, I’d prefer if the unit used standard AA batteries which can be easily and quickly swapped out in the field if needed.

The tube used by this meter is the J321 which is a glass tube and it is ok. It gives around 20 CPM of background and it is able to detect hard beta, gamma and Xray radiation. Compared to other Chinese tubes, it is definitely much better but I wouldn’t call it an ideal design. I’m still waiting for Chinese manufactures to create a tube that can truly rival and beat the good old SBM-20, especially as its supply really dried out in the recent years.

On the bak of the unit there are small opening in the body which allow beta particles to reach the GM tube however there is no beta shield, which is a big bummer as it makes all the dose reading in uSv/h, pretty much pointless as beta activity will highly inflate them. I would really like to see a removable beta shield like on the Terra-P meters added to the future models. Luckily there is a CPM and even CPS mode but with low sensitivity of the J321 tube, I think the CPS is really unnecessary and I would just stick to using the CPM.

When considering the FS5000, make sure that the listing explicitly states that the meter comes with J321 and not some other generic GM tube. While reading through some forums, I noticed that some of these meters came with alternative tubes which have much worse performance and should be avoided.

So how does the FS5000 perform?

I tested my FS5000 meter against a few of my sources which include a negative ion pendant, a thorium gas mantle, a coin made out of pure lutetium metal and a high grade Uranium ore.

As mentioned previously, the FS5000 doesn’t have a beta shield which makes the dose rate reading irrelevant so I will be using the CPM as they display the raw data from the detector. Remember that CPM are dependent on the tube used by the meter and the results measured with a J321 will be vastly different from ones measured with the LND7311 found in my Ludlum 44-9 probe which I normally use.

After conducting the stress test, I notice another big problem with the FS5000 meter. It takes a while for the readings to comedown back to background radiation levels after measuring hot samples.

Rad Pro Upgrade

As we discovered, the main issue in most of these cheap Geiger counters is a bad firmware. It usually has slow averaging time which doesn’t adjust to sudden changes in activity resulting in very slow calculation of the measurements. When compared to my RAYSID or my MKC-01CA1M, the FS5000 doesn’t even come close. This is a serious issue which always made me recommend against buying cheap meters.

However, the community is great and a guy called Gissio wrote a custom firmware called RadPro which addresses most of the firmware issues. After installing it, the FS5000 became much more responsive to sudden changes in activity and the new firmware also brought a bunch of new features, which really elevate the usability of the meter.

The only real downsize of this new firmware is that the device eats through the battery much quicker but I think it is a worthy sacrifice. Hopefully this can be optimised in a future update.

I definitely recommend checking it out if you have one of the following meters:

FS2011, YT-203B, Bosean FS-600, Bosean FS-1000, Bosean FS-5000, FNIRSI GC-01 and JOY-IT JT-RAD01

Link to Rad Pro: https://github.com/Gissio/radpro

Summary

The Bosean FS5000 has positively surprised me with its value for money, especially after installing the custom RadPro firmware. It definitely won’t be replacing my other meters such as the Terra-P or the MKC-01CA1M but I wouldn’t hesitate to recommend it to someone who is just starting out and looking to buy their first cheap meter to begin their journey with radiation detection.

I want ot hear from you! Do you have the FS5000 meter? What are your experiences with it and do you use the custom Rad Pro firmware with it? Let me know, in the comments below!

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Thank you so much for reading this post, I hope you enjoyed it and learned something new! If yes, please make sure to subscribe to the email list so that you get notified when new posts are added. Also feel free to check out my Ko-Fi page where you can donate a nice cup of radioactive coffee and support my work financially.

and remember, stay active!

Welcome back my fellow radiation nerds! Today we will dive deep into what is arguably one of the best radiation meter out there, the Ludlum Model 3!

The history of Ludlum Meters

The Ludlum Measurements, Inc. was established in 1962 by Don Ludlum, who was an engineer with a background in designing radiation detection equipment. Not long after, it has produced its first commercially available meter, Ludlum Model 2. Ludlum’s official YouTube channel has a very interesting video on one of the very first units ever made with a serial number of 31, which I have linked in the description below.

His meters quickly gain popularity and good reputation for their reliability and long use life, which quickly established Ludlum Measurements as a trusted name in the world of radiation detection. The success of the initial models paved the way for the development of a wide range of survey meters and radiation detection equipment that continues to be used around the world to this today.

The versatility of Ludlum Meters.

Ludlum meters are the go to meters for many scientists and first responders, because of they are extremely rugged, reliable and easy to use design. Furthermore, Ludlum Measurements offers a wide range of probes and accessories which can be easily swapped out for various applications. Adding the long and proven track record, it is easy to see why Ludlum meters became the preferred choice for scientists worldwide.

Different Ludlum models

If you look at Ludlum’s product range, you will quickly realise that there are a bunch of different models out there. However for the personal use purpose, I think these are the ones worth considering.

Ludlum Model 2 – It is most basic, analog meter that Ludlum made (discontinued but can be found used). It has the 3 operating mode x0.1, x1, and x10 which might not be enough if you plan using it with sensitive detectors such as scintillator probes.

Ludlum Model 3 – A step up from Model 2. It offers extended measuring range (x100) and improved circuitry and electronics.

Ludlum Model 12 – Supports internal voltage measurement for easy switching between different probes which might require different operating voltage. For that reason, it also has an extended voltage range (400 to 2500 Vdc).

Ludlum Model 14c – Overall similar to Model 3, however it houses a small, gamma compensated GM tube which automatically operates when the scale is set to the x1000 mode.

Ludlum Model 2221 – Digital scaler/ratemeter with advanced data logging capabilities, often used for more precise and detailed measurements.

Ludlum Model 2241 – General-purpose scaler/ratemeter with a digital display.

There are plenty more of Ludlum models out there and if you want to learn more about them, I encourage you to read the detailed description on Ludlum website (click here).

Technical data and features of Ludlum Model 3

The Ludlum Model 3 has a range from 0 to 500,000 CPM and can supply voltage to the probe between 400 and 1500V. This flexibility allows it to work with a wide variety of detectors, including scintillators and some neutron detectors. Most of the time, I pair mine with a 44-9 probe, however I do change that occasionally depending on the situation

The meter features a rotary switch for selecting different measuring ranges and performing a battery test. It also includes both slow and fast averaging modes, which are particularly useful for obtaining accurate readings in varying conditions.

Powered by two D cell batteries, the Model 3 offers approximately 2000 hours of use. The batteries are housed in a separate compartment, which helps protect the electronics from potential damage in case of battery leakage. Additionally, all parts of the Ludlum Model 3 are sealed to prevent moisture from entering the meter, enhancing its durability.

These features clearly demonstrate that Ludlum meters are built to last and why they’ve earned their stellar reputation.

My Ludlum Model 3

I acquired my Ludlum model 3 a few years ago, and it has been my primary meter ever since. It has a serial number of 104163 and it was manufactured on April 16th, 1992. Despite its age, it operates flawlessly, having only small scratches from regular use. In order to ensure accurate readings, I calibrated my unit using a pulser made by GEOelectronics.

My unit has meter face showing only CPM. If you have seen my previous video on how to measure radioactivity, you know I am not a fan of dose units when used to measure activity of samples, so this works perfect for me. Ludlum does offer different meter faces for different probes, however I’d still recommend to sticking with the CPM.

Originally, my meter came with a “C” type connector, which is common on most Ludlum devices. However, this connector is hard to come by in Europe, so I replaced it with a BNC connector. This modification has made it much easier to find compatible cables and probes. The meter also came equipped with latches for a strap, which, while I don’t use them often, are a handy addition for prolonged use, as the meter can get heavy. Lastly, I crafted a probe holder for my 44-9 from a sheet of metal. While it’s not the most aesthetically pleasing, it gets the job done. I’m also thinking about adding a check source holder to the side of my meter, however I can’t seem to find one for a good price.

How to buy a Ludlum meter?

So, you want to buy a Ludlum meter. But where can you find one?

If you’re set on a brand-new meter, you can purchase directly from the Ludlum website. However, be aware that their prices are generally aimed at labs and government agencies, not private individuals. A new Ludlum Model 3, for example, costs around $1,000, and that’s without any additional accessories or probes.

In my opinion, it’s a far better choice to buy a used (or refurbished) unit online. Labs occasionally clear out old inventory, and this is the best time to find used meters and probes at a relatively low price. I got my meter during one such sale for fraction of what a new one would cost me.

When evaluating a used meter, ensure it’s in good visual condition (no dents, corrosion on battery ports or cracked glass). Ludlum meters are mostly analog, making them easy and inexpensive to repair if any internal parts fail. This being said, I noticed that newer Ludlum meters are made with a PCB which use those micro components which are much harder to work with unless you have proper tools for it.

Alternatives to Ludlum

Ludlum isn’t the only company producing high-quality radiation meters. Brands like Eberline and Johnson also offer fantastic meters that are worth checking out, often at a lower cost than a Ludlum.

For example, I found my Eberline 120 survey meter (which is similar to a Ludlum model 2) that came with an HP260 probe and a check source holder for a total of 110 British pounds, including shipping!

Good deals are out there—you just need to be patient and keep an eye out, and eventually, one will pop up.

A few final words

Ludlum meters are the industry standard for a reason, and I highly recommend checking them out. Their professional build, high performance, and versatility are what led me to purchase one for myself, and I have absolutely no regrets.

I’m curious to hear about the meters you use for your measurements. Do you have, or are you planning on investing in, a Ludlum meter? Let me know in the comments!

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Thank you so much for reading this post, I hope you enjoyed it and learned something new! If yes, please make sure to subscribe to the email list so that you get notified when new posts are added. Also feel free to check out my Ko-Fi page where you can donate a nice cup of radioactive coffee and support my work financially.

and remember, stay active!

Welcome back my fellow radiation nerds, Today we are taking a closer look at the BetterGeiger S-2 meter and if it’s really a better geiger counter!

Geiger counters are one of the most common tools for measuring the radiation around us, but they’re not perfect. They often suffer from limitations such as inaccurate dose rates and low sensitivity which are a characteristic of the Geiger-Muller tube used by the most meters.

In the recent years, there has been a surge in products that use small scintillation crystals instead of the more traditional GM tubes but they are usually more advance devices, target at experienced users, not entry level amateurs

This is where the BetterGeiger S-2 meters comes in

BetterGeiger S-2

First things first, I would like to thank Robert from Better Geiger who was kind enough to provide me with the S-2 meter making this video possible.

The Better Geiger S2 is a personal radiation detector manufactured in Colorado, USA. It is made out of high quality plastic which feels solid and durable and for extra protection, the unit is wrapped in a rubber case which should prevent it from any fall damage if it would slip out of hand.

While slightly on the bigger side, it can be operated singlehandedly and navigating through the menus and setting was pretty simple and intuitive.

Despite its name, Better Geiger does not use a geiger muller tube. Instead it has a small scintillation crystal which gives about 100 CPM of background activity and is rated for a maximum dose rate of 100 mSv/h for Cs-137.

Unlike most geiger counters, BetterGeiger factors in the different gamma energies detected to give accurate gamma dose readings. The measurements can be displayed as uSv/h, mRem/h or CPM and the unit does also has an alarm feature which threshold can be adjusted to the user’s preference.

While it can detect some strong betas, it’s not particularly sensitive to them and I think it’s better to think of the meter as gamma only.

When compared to my other meters, the BetterGeiger showed much higher sensitivity to gamma radiation which is particularly helpful when looking for radioactive minerals. I got a few uranium hunting trips planned, and I’m very excited to take the meter with me and see how it performs.

Improvements for the future BetterGeiger S-3

I really did enjoy using the BetterGeiger S-2 meter, however I see some potential improvements for future versions to make it even better.

The firstly, I would love to see a bigger sensor which would increase the sensitivity of the meter.

Secondly, I would move the sensor to the top of the meter. At the moment it is facing the user, making it hard and impractical to measure different sources, as it’s not always easy to see the readings on the screen.

Thirdly, I would like to see an improved algorithm which would quickly adjust the readings when there is a sudden increase in activity but then stabilises once the correct measurement is reached. The one currently used is definitely not bad and does the job well but it would make the unit faster and more responsive.

Lastly, the plastic used over the display screen is way too soft which makes it very easy to scratch. I would to see it replaced with a harder one that is more resistant to wear and tear of everyday use.

So, is it worth it?

Considering that the unit is priced at just under 150 dollars, I think it is a good alternative to many other meters in the same price range. I love that it shows accurate gamma dose readings and that it has a higher sensitivity to gamma radiation than a conventional geiger counter. While it isn’t the perfect tool for everyone, as it doesn’t detect beta radiation very well, I think it’s still solid meter offering something new and unique to the market.

I want to hear from you. What are your thought about Better Geiger S-2 and do you have any experience in with it? Let me know in the comments below!

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Thank you so much for reading this post, I hope you enjoyed it and learned something new! If yes, please make sure to subscribe to the email list so that you get notified when new posts are added. Also feel free to check out my Ko-Fi page where you can donate a nice cup of radioactive coffee and support my work financially.

and remember, stay active!

Youtube Video

Welcome back my fellow radiation nerds! Today we will dive deep into how to calibrate Geiger Counters so that they show true readings!

If you are collector of old, vintage Geiger counters then you know that they are not only they are built like tanks but also have a certain character and feel to them. Unfortunately, the calibration on them might be a bit off as a result of their ageing components. Today I want to show you how you can easily calibrate your Geiger counter so that it shows accurate readings again!

In order to do this you will need:

• a multimeter with 2 probes and a 1G Ohm (1000M Ohm) resistor for measuring the HV
• a pulser
• and your Geiger counter with a cable to connect a GM probe

Firstly, you will need to check if the voltage on your meter if it is correct using a multimeter and a 1G Ohm resistor. I already made a post about it which you can find HERE.

The next step is to connect the pulser in place of the probe. Pulser will generate “clicks” at a consistent rate which will allow us to calibrate the meter. I personally use one made by GEOelectronics and I highly recommend it but others should also work fine.

Now turn on your meter and set your pulser to generate a desired amount of CPM. Make sure that the needle on the meter is showing the correct amount of CPM generated by the pulser on every scale. If it is not, then adjust the calibration potentiometer until it sits right where you want it.

If your meter uses dose units such as uSv/h, then you will need to find a conversion rate from CPM to uSv/h for the Geiger tube used in your meter. THIS post by DIYGeiger covers most of the GM tubes commonly used and gives a rough conversion ratio from CPM to uSv/h. Please note that this isn’t very accurate and if possible, you should use CPM when measuring activity of a samples. Dose units work only when the meter is calibrated to the specific isotope which is being measured. In other cases, the readings can be lower or higher than in reality.

Congratulations, you have now successfully calibrated your Geiger counter! However if you are a professional and you want the most accurate calibration on your meter, then you should most probably send your meter for calibration to a professional lab but for most hobbyists, this method should be more than enough!

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Thank you so much for reading this post, I hope you enjoyed it and learned something new! If yes, please make sure to subscribe to the email list so that you get notified when new posts are added. Also feel free to check out my Ko-Fi page where you can donate a nice cup of radioactive coffee and support my work financially.

and remember, stay active!

Recently, I have acquired an Eberline 120 survey meter however since it is pretty old, I was a little bit worried that the voltage coming from the unit might be too high for the probe due to the age of the internal components so I decided to measure it just to be sure.

Unfortunately, if you are going to measure the voltage using a cheap multimeter, you won’t get an accurate reading. That is because the impedance on the multimeter is different from the one on the Geiger counter. An easy way to fix this issue is simply to add a 1G Ohm (1000M Ohm) resistor between the positive probe and the Geiger counter.

Now simply set the multimeter to the 2000mV and connect probes to the BNC connector on the Geiger counter. The number on the display of the multimeter shows the voltage coming from the Geiger counter.

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Since I have a lot of Geiger counters, I have decided to make my own probe with a 1G Ohm resistor built into it. Whenever I want to measure the voltage in my meters I can quickly change the standard probe for my moded one!

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Here is another great post on this topic:

https://ea4eoz.blogspot.com/2012/09/one-gigaohm-high-voltage-probe.html?fbclid=IwAR35wkE80V-yRVkkodyz_Gpa6DZnuyyPXcLMwAthdo9z8kKJjrWDpUucpsY

Today I want t show you a device that allows you to do gamma spectroscopy on the go! Let’s take a closer look at the RAYSID Gamma spectrometer.

RAYSID is a gamma compensated dosimeter, gamma spectrometer and radiation mapping/logging device all in one small package. There are 4 models with the cheapest being 300 euros and the most expensive being 600 euros. All of them have exactly the same features with the only difference being the value of the FWHM which is important only when doing gamma spectroscopy. So if you are not interested in doing gamma spectroscopy then you will be perfectly satisfied with the cheapest model but if you would like to do gamma spectroscopy then I would suggest you invest in the slightly more expensive model.

In terms of size, RAYSID is comparable to a Zippo lighter and weighs only 65 grams. Inside there is a rechargeable battery that lasts for over 10 days on a single charge. The heart of this device is a 5 cm3 Thallium activated Caesium Iodide (CsI(Tl)) scintillation crystal.

Inside the box, there is a manual, USB charging cable, caring case, selfie stick with a holder for RAYSID and RAYSID itself.

In order to use the RAYSID

to its fullest potential, it is best to connect it with RAYSID app. Unfortunately, the RAYSID app does NOT work with iOS and is only compatible with android 5.0 (or higher) devices.

In order to turn the unit on, we simply need to press the power button. Next, we can open the RAYSID app and connect RAYSID with our phone. In order to turn on/off the speaker simply press the power button once. To turn the unit off press and hold the power button.

Search mode

Search mode is useful when searching for radioactive hot spots. The upper side of the screen displays a graph showing current CPS and the dose while the lower side shows the rough gamma spectrum which is updated in real-time.

On the right side, there is a set of icons. The first one locks the display in the current position (vertical or horizontal). The camera icon allows you to take a photo with the current measurements.

Gamma Spectroscopy

One of the best features of RAYSID must be its ability to do gamma spectroscopy. Depending on the model, FWHM varies from >15% to <8.5%*. The smaller the FWHM the more accurate and narrow peaks. For the best result, it is best to have FWHM below 10%.

As of right now, the spectrum range is from 25 keV to 1000 keV which means you should be able to identify the most common radioactive isotopes such as U-238, Th-232, I-131 or Cs-137. In a future update, the range will be extended to 3000 keV allowing for the identification of radioactive isotopes such as K-40 or Co-60.

Another great feature is that RAYSID has a temperature compensation which results in the spectrum not being affected by the weather (in extreme cold or heat, spectrum mode is unavailable). Manual calibration can be done in the “settings” tab.

What I really like is that when doing a gamma spectrum, the app automatically identifies different isotopes based on their energy peaks which means you don’t need to analyse the spectrum to identify the isotope you are measuring. The average dose and CPS are also displayed.

It is also possible to save the background spectrum which helps visually to see any minor differences when measuring samples for a trace amount of radioactive contamination. In order to do that simply click on the “BG” icon with a “download” arrow. This will save the current spectrum as background. You can toggle on and off the background spectrum by pressing the “BG” icon.

Triple pressing the power button will restart the spectrum

*FWHM measured at 662 keV

Map

Since RAYSID is so small, it is very portable and you can take it anywhere you want. What is even better is that it automatically makes a map of background radiation anywhere you go! You can set the map to show background dose (uSv/h, uR/h) or background activity (CPS, CPM and Bq/m2 (only for Cs137)).

To enable global map press the “web” icon. If you wish to share your map with RAYSID global map than press “share” icon. If you want to delete point on the map click the “bin” icon and hover the red square over the points you want to delete

You can have a look at the current state of the map by clicking HERE

Alarm & Log

A CPS or dose alarm can be set in the “setting” tab. When an alarm is trigger, it will be logged in the “Log” tab. Double pressing the power button will turn the alarm on or off.

Conclusion

I personally think that RAYSID is the best device of its kind. Relatively low price and very good performance make it one of my favourite radiation detectors in my collection and since it is so portable, I take it everywhere with me! So if you are in the market for a portable gamma spectrometer I highly recommend the RAYSID.

Gamma-Scout is an iconic Geiger counter but is it any good? Let’s find out!

Before I start, I must say that the unit that I got is not stock. It has a new battery and the GM tube was swapped for Philips ZP1400 since the original Ludlum LND712 was broken. Lastly, I have also added a metal mesh in front of the GM tube for some additional protection when measuring alpha radiation.

The version I got is the Standard model which retails for around 380 euros. Gamma-Scout offer three other models. Alert model which has an audible clicking sound and a settable alarm, a rechargeable model that has a rechargeable battery and an Online model which allows user to connect the Geiger counter to PC wirelessly.

Despite the fact, the GM tube was not original, the results I got were fairly similar to my other Geiger counters which meant that Philips ZP1400 is a very good alternative to the LND712.

One small design issue that I noticed with the Gamma-Scout is that the GM tube is slightly pushed back into the meter. This means that detecting alpha particles will be more difficult since they have a very small range.

What I really like about this meter is that it can detect alpha, beta, gamma radiation and it shows readings in dose units as well as raw activity (CPS).

Unlike most electronic devices, Gamma-Scout has no on/off button. It remains always turned on until the battery dies. Luckily, this unit is designed to run for over 10 years without the battery running out, and if it does, Gamma-Scout recommends sending the unit back to them for battery replacement and calibration but in my experience, it is fairly easy to replace the battery by your self if you know how to solder.

Unfortunately, this meter also has some downsides. There are some quality control problems including the radioactive logo being distorted and the upper and lower body parts not fitting perfectly even with screws tighten. These are small issues but they should not exist on a Geiger counter that cost almost 400 euros!

What bothers me the most is that the standard model does NOT come with a speaker! In my opinion, a clicking sound should be a standard feature on EVERY modern, handheld Geiger counter. Even my cheap 30 euro DIY Geiger counter has a tiny speaker built-in. If you want audible clicking sound then you need to buy a more expensive Alert model.

Overall, I think that Gamma-Scout is a-OK Geiger-counter but it feels outdated and I find it to be overpriced. That is why I would not recommend the Gamma-Scout standard model and I would suggest looking at other meters from the competition. A good alternative that comes to my mind would be Radiascan 701.