Geiger Counter Nuclear Radiation Detector - FNIRSI Radiation Dosimeter with LCD Display, Portable Handheld Beta Gamma X-ray Rechargeable Radiation Monitor Meter, 5 Dosage Units Switched

Before I begin, I need to say that this is a Geiger counter that has been designed to be a dosimeter. It measures the accumulated radiation exposure in fractional units of Sieverts over time. This is a high quality dosimeter considering the price. It can read gamma, beta and x-radiation dosages. Two screens are provided: the first is numerical and the second is graphical. The manufacturing quality of this instrument is evident at first glance. It is beautifully packaged in order to protect the Geiger-Mueller tube in shipping which is otherwise subject to shock breakage. I purchased this item in order to monitor radiation dosages in two places in my home. The first is an activated charcoal filter that I have on my water supply in the basement while the second is a reverse osmosis system with charcoal filters under the kitchen sink. Since there is radon in my well water supply, I prefer to remove as much as possible before it is delivered to the faucets in the house. It also serves to reduce the radon levels in air due to cooking, washing, showering and laundry. Capturing the radon in activated charcoal will also capture radon decay products (daughter products). Some of these have very short lifetimes, but some are extremely long and tend to build up in the activated charcoal filters over time. I wanted to see how these radiation dosage levels increased over time in order to determine the optimal time to change the filters. The first thing that I noticed was that in just one week, after a basement filter change, the radiation had already built up by a significant amount. The radon radioactivity in our water is approximately 3000 pCi/L. If allowed to vaporize due to cooking, washing, bathing and laundering, this amount of radiation could add about 0.3 pCi/cubic meter to the air. The radiation dosage level that was measured close to the tank was 1.4 uSv/hr according to the meter. If multiplied by the number of hours in a year, 8760, we arrive at the accumulated dose per year which is 12.3 mSv. This is the amount of radiation exposure that would be possible were a person to stay in proximity to the tank for an entire year. This exceeds the NRC dosage guidelines of 1 mSv (0.1 rem) per year. Clearly, the filter should not be placed anywhere near where people or children would normally gather or play, for example, a finished basement. I will be monitoring the activated charcoal filter tank for several weeks to see if the radiation buildup reaches equilibrium as the filter capacity is exhausted. This will provide a guideline for how often the filter should be replaced. Short term exposure to the filter during a filter change should not be an issue provided that safe handling practices are followed. As a followup, I have decided to change the activated charcoal filter in the basement four times per year since no one is in proximity to the filter most of the time. One additional piece of information: For occasional proximity to radiation by workers, the annual permissible dose is 50 mSv (5 rem) per year. On the subject of radioactivity and dosage; they are not the same, pCi/L cannot be converted to uSv, or vice versa. The first is an instantaneous radiation level in disintegrations per second from a liter of water, while the second is an accumulated exposure dosage over time. Finally, I am not a licensed professional engineer or health physicist. Always consult with a professional engineer or health physicist who is. Most water system installers pose as being knowledgeable, but they are not. While they may attend training courses in radon mitigation, they do not possess the knowledge required to make sound health decisions for your family.

I don't know much about the math involved with this device, but I was able to get various readings off of a large variety of vaseline glass/uranium glass items. I only needed to hold it in place for a few seconds and I could at least verify that I could get anywhere from 2 to 6 times as much radiation off of those items (depending on the item) as what I get from normal background radiation. I do not believe that my purchase was giving baloney readings, though it is still possible the device is not as sensitive as it should be. However, 2 to 6 times is about what I should expect from uranium glass. I did experience some trouble turning on the device after turning it off the first time. I followed someone else's advice and stuck a pin into the small hole at the bottom while holding down the power button. That seemed to reset it.

OK this was one of these items that I really didn't have to have but wanted to get. I was first attracted to the price point for a functional Geiger counter and it has some nice options with it. This counter uses a GM tube I do believe and appears to give me consistent readings when using it with a known radioactive source. It will detect xray, beta and gamma particles and I really like the screen and setting options. Battery life for me has been super good and I like the size and feel in my hands. It is very easy to use but I will say that an area that it could improve in is it's ability to detect and display radiation doses faster and I do wish that it would give the characteristic clicking sound when the GM tube is struck by radioactive particles. So speed of detection and that sound are my only real complaints. I guess both of these are typically available on higher priced units. All in all, I'm very happy with my purchase and it's cool to check out uranium glassware, gas lanterns mantles and smoke detectors. Hope that it works well for a long time to come.

Fun purchase works great for in or outside the vault!