Radiation Detectors: Gamma Scout Review

I purchased the Gamma Scout Alert Model radiation detector last year, after my previous radiation detector (from a different company) failed. I’m very pleased with the Gamma Scout. It is a feature-rich well-designed Geiger counter, made in Germany.

The Alert Model takes its name from its automatic alarm, which will sound if radiation exceeds a certain level. That level is preset, but can be changed by the user to a higher or lower level of radiation. I consider this particular feature, an automated alarm, to be almost indispensable in a radiation detector. What if a nuclear power plant disaster occurs at night? What if the authorities are negligent in warning the public promptly, about the same disaster during the day? The alarm feature is well worth the $50 or so above the base model price.

The overall feature set of the Gamma Scout detector is very robust. All four models have essentially the same features, except for a few differences.

1. Standard Model — no ticker or alarm; battery is not rechargeable; no ability to download data to a computer.
2. Alert Model (my choice) — ticker and alarm; battery is not rechargeable; no ability to download data to a computer.
3. Rechargeable Model — ticker and alarm; battery can be recharged via USB cable or external power supply (included); no ability to download data to a computer.
4. Online Model — ticker and alarm; battery is not rechargeable; has real time data download: connects to Windows PC and sends the data measurements (pulses) in intervals of 2 seconds.

With the ticker feature, the user can turn on an audible click that will sound whenever there is a “count”, meaning the detection of a particle or ray of radiation. This is useful when radiation levels are low. In case of a radiological event, these clicks become so frequent that the number of individual clicks cannot be discerned. In such cases, simply turn off the ticker and use the LCD readout of the radiation level.

All the Gamma Scout models can detect alpha, beta, and gamma radiation. The only radiation that cannot be detected by this device is neutron radiation. Only much more expensive radiation detectors are designed to detect neutron radiation. For the average user and many professionals, alpha, beta, and gamma detection is sufficient. Radioactive fallout does not generally emit much neutron radiation.

Compared to my previous radiation detector, the Gamma Scout is larger and more complex; it has more features, and greater flexibility in usage. The plethora of features is an advantage and a disadvantage. You have to spend some significant amount of time with the device and its user manual. Nothing about this device is intuitive, except its alarm, when excessive radiation is detected. You also need to do some reading to understand what the different radiation levels mean. Otherwise, the LCD readout of radiation level would be just a meaningless number.

On the other hand, once you understand how all the features work, it is an extremely useful device to have in a radiation emergency. It is an accurate and full-featured professional radiation detector.

How do you turn on the device? You don’t. It is always on, and the battery is rated to last about 10 years under normal usage. In any case, you want the device to be always on, so that the alarm will be able to sound at any time, if high radiation is detected.

The top of the device has a ‘diaphragm aperture’, which allows radiation into the device for measurement. At the top front of the device is a large gray switch. Keep the switch, in most cases, in the middle position, which is for detecting gamma (and x-ray) radiation only. Pushing the switch to the left moves a thinner metal plate between the detector and the external radiation source, allowing through beta and gamma radiation, but not alpha radiation. Pushing the switch all the way to the right exposes the radiation detector tube to the exterior, so that gamma, beta, and even alpha radiation can reach the detector. Don’t put the switch in this position, because it makes the detector tube more vulnerable to breakage. Keep the switch in the middle position, unless you know what you are doing and have some specific reason for detecting beta or alpha radiation.

The normal mode of the Gamma Scout uses microsieverts (uSv — one millionth of a sievert) per hour, not rads or rems per hour. A Sievert (Sv) is the standard international (SI) unit similar to the rem; it is a measure of radiation dose, which takes into account the type of radiation and its health consequences on the human body. 1 Sv = 100 rem. For normal background radiation, the uSv/hr should be well under 1.0, and typically about 0.1 to 0.2 uSv/hr.

The Gamma Scout has a pulse count mode, which counts the number of radioactive particles or rays as a cumulative number, and a pulse rate mode, which counts the average number of pulses per second. The pulse modes are less useful than the microsieverts per hour mode, because the microsieverts units are weighted to take into account health effects. An audible ticker can also be turned on, during the microsieverts mode, so that pulse counts are heard, but the display is in uSv/hr.

The Alert Model is set to sound an alarm (a beeping sound) when the radiation reaches 5 uSv/hr, which is 25 to 50 times background level. The alarm threshold can be changed by the user to a higher or lower level.

The Gamma Scout also has a cumulative dose setting, that continuously adds up your exposure in the background, while the LCD displays instead the uSv/hr. You can program the device to keep track of cumulative dose (in millisieverts, not microsieverts) for any set amount of time. So if you want know what your exposure has been per day, in addition to per hour, you can set the device for one day. This mode is very useful, but complicated to set up; see the user manual.

The Gamma Scout is larger than some other competing devices. It is about 6.5″ x 2.8″ x 1.2″, and is a bright orange color. An optional leather case is available, which has cut-outs and a plastic window, so the device can be used while in the case. The device is light, and narrower in the middle, so that it is easy to hold while pressing buttons.

On the subject of price, I feel obliged to point out that, when the Fukushima Japan nuclear power plant disaster occurred, and demand for radiation detectors skyrocketed, the company that makes the device kept their prices at a reasonable level. They did not increase the price in accord with the increase in demand. The current price for the Alert Model, as of this writing, is $489.00 US dollars. (As always, prices are subject to change.) This price range is reasonable for a device of this feature set. You can find cheaper radiation detectors online, in particular certain models made in Russia. You can find smaller and less expensive devices with a greatly reduced feature set (such as the NukAlert). But in my opinion, the Gamma Scout has the best combination of features and price.

On the subject of availability, in the aftermath of Fukushima, they quickly ran out of stock and lead times increased to over 5 months. If you wait until a radiological disaster occurs, even if that disaster occurs in another country, radiation detectors will be nearly impossible to obtain. So if you are prepping for any type of radiological disaster — nuclear power plant disaster, dirty bomb, nuclear bomb explosion — really you can’t wait until the disaster occurs before getting a Geiger counter.

– Thoreau

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