GQ Geiger Counter GMC-800 Nuclear Radiation Detector American Design US National Standard Dosimeter with Global Data Logger & Sharing Beta Gamma X-Ray Portable Device

For this review, I've uploaded my side-by-side background radiation comparison photos of this new American GQ GMC-800 Geiger Counter with the readings given by two far more expensive high-end, calibrated scintillation counters: a Thermo Radeye with external dual phosphor probe, and a Radiagem with a 2x2" NaI phosphor external gamma probe. The background readings are in a relatively high background region of Cornwall, not very far from the old South Terras Uranium Mine). Note that 300 nSv/hr = 0.3 uSv/hr, so that a GMC-800 reading of 0.3 uSv/hr is identical to the Radiagem's 300 nSv/hr. The American GMC-800 is accurate, lightweight, pocket sized and has just the features you need to rapidly check background gamma radiation. It will display counts/second, milli-Roentgens per hour (for the imperialists), uSv/hr, or counts/minute. The GMC-800's manufacturer's geiger tube gives 25 counts/second per mR/hr or per 2.5 uSv/hr (they use the RBE=1 conversion whereby 1 mR = 10 uSv). It also functions as a dosimeter, so you scroll through the options to display accumulated dose. You can also set the alarm threshold however high you like. Accuracy is within +/-20%. It comes with USB data and charge cord, a 3.7v lithium ion rechargable battery (AA sized) which is removable via a battery cover on the back, a soft dust proof case, and instructions plus radiation safety data "credit card" for a wallet, listing radiation levels and precautions needed. To turn it on, you need to hold the on/off button down for 4 seconds (probably to prevent it accidentally being turned on or off by keys or change in your pocket). The only disadvantage is that the AA sized 3.7v lithium ion battery cannot be substituted for a common AA 1.5 v battery in an emergency (it needs over 3v and won't work with a common 1.5v AA battery, I checked this). So you might want to buy a spare 3.7v lithium ion AA sized battery, or take a USB charge cable and portable phone charging power pack with you, if you want to ensure you don't run out of power. By default it makes a soft click every time a gamma ray is detected, the LED light above the display screen flashes with every "count". You can customise these settings. I have previously "tried" to buy two cheaper pocket geiger counters of other brands on Amazon, but both have been defective and been returned (I don't like reviewing totally defective products, as there's nothing to say and of course occasionally items are damaged in transit so you can't necessarily blame the product itself, which would create a misleading "review"). This American GMC-800 is brilliantly designed to do a straightforward job, does that job well, and I recommend it to anyone who needs to measure radiation.

Very good product

I have been looking at Geiger counters for years, but haven't been able to justify the expense (until now). Basically, I wanted it because while I don't personally work with radioactive materials or radiation, I do work with people who do, and contamination does happen. So basically I was looking for something for everyday carry. I was also interested in confirming that granite and quartz counter tops, as well as tiles, were not radioactive. I also know a lot of people with antique china (some of which is radioactive). Okay, I mostly wanted it as a gadget, but okay, I also wanted it as a prep (eyes rolling). No seriously, if you ever actually need a Geiger counter as a prep, it might be too late to buy one. So I have a few basic preps, and now this is one of them. People often wear those little radiation dosimeter badges. I have often thought this was a bit weird, because basically they tell you that you were exposed a couple of weeks ago. Whoops - it would have been nice to have known that when the exposure was happening, so you could have stopped it. So I have been looking at a number of Geiger counters for a while, and the thing that pushed me over the edge, is that the cat was about to have I-131 treatment for hyperthyroidism (this is where the patient, in this case our cat, is injected with radioactive iodine to treat hyperthyroidism). The patient (again in this case our cat) ends up fairly radioactive for a few weeks. My biggest problem upon receiving the device is that I had no way to test it. I could find literally nothing in the house that was radioactive (thank goodness). None of the china was radioactive, none of the tiles and countertops are radioactive, and I couldn't find a single old watch or clock (i.e. with radioactive glow in the dark hands). When the cat's treatment started, this problem was solved. The cat was hot, the cat's thyroid was even hotter. The litter box was hot. The cat's vomit (sometimes invisible, except to the naked foot) was hot, and the cat unfortunately in one instance missed the litter box, so then that spot of carpet was hot. I really like the device. It has a very nice display and menu options. The battery life is great: I haven't checked, but I think it lasts more than 24 hours with the display continuously on. I like that it has a rechargeable battery that you can replace, and I like that you can recharge the battery via USB-C (i.e. while the device is running). I like that it has an alarm, so if the cat sneaks up on me, I know right away. The device is very light, so I can put it in my bag and forget that it is even there. Based on what I know, GQ is quite a reputable company in the affordable Geiger counter space. The plastic looks a bit brittle, but in practice I have (unfortunately) whacked it and dropped it a couple of times, without incident (thank goodness). There are still a few Geiger counter features that I would like (again, mostly thinking of this like a gadget): - A large and sensitive paddle tube - A mica window to detect alpha particles - A gamma spectrometer I also really like the idea of ultra compact Geiger counters (like keychain ones) for everyday carry, but in practice there is a tradeoff between size and sensitivity. One thing that would be really nice for everyday carry is bluetooth connectivity. It occurs to me that one of the most likely reasons to be exposed to radiation, is if someone you know is having some sort of medical treatment and hasn't told you. It would be super embarrassing if you were in a conference room, and your Geiger counter were to go off, because surprise, your boss's boss is having brachytherapy for prostate cancer. Awkward. So for everyday carry like this, it would be better if the device were just to inconspicuously show a notification on your phone. So I don't know if this will be my last Geiger counter, but this is the one that finally bought, after years of wanting one. All in all, I would say that the perfect Geiger counter is the one that you actually own, and that you are carrying when you are exposed. This is the one that pushed me over the edge, and so for me, right now, I would say this is the perfect Geiger counter.

Product is just as described! Extremely satisfied !

Simplemente genial. Es un gran contador Geiger Muller. Tecnología USA perfecta. La batería dura muchísimo. Muy buena calidad. Mediciones bien calibradas. Mide por conteo por segundos y por conteo por minutos. Mide tanto en microsievert/ como en milirem/h. Tiene dosímetro. Tiene varias formas de alama. Alrma programable. Es muy fiable y mide correcto en relación con mis otros Geigers. Viene con funda protectora. Se puede actualizar su firmware. Una compra muy recomendable. Lo recomiendo.