Question 1

Can this measure radiation in ocean fish?

Accepted Answer

This is a complex question. The GCA-07W can detect alpha, beta, x-ray and gamma radiation. Checking fish or food for radioactive contamination is a little difficult and Geiger counters, (from us or any other manufacturer) is not the ideal instrument to do so, here's why. The GCA-07W Geiger counter can detect alpha radiation. However if the fish (or food) being tested has a alpha radiation emitter internally, the food itself will block the alpha radiation and stop it from being detected. If the alpha radiation contamination is on the surface of the fish (unlikely), it can be detected. Similarly, if the fish has a beta radiation contamination internally, let's say a SR-90 contamination,  the water in the flesh of the fish will effectively block the beta radiation from being detected. Again if the beta contamination is on the surface of the fish (unlikely), it can be detected. With gamma radiation the situation changes. Gamma radiation can penetrate the flesh of the fish to be detected. The problem arises is that low level contamination gamma radiation from let's say a CS-137 contamination will be indistinguishable from normal background radiation. So to test for this contamination , one method a laboratory may perform is a gamma spectroscopy (scintillation detector) to determine the source of the radiation.    In the case of testing for alpha and beta radiation mentioned before, a lab might incinerate the food or fish in question down to ash. Without the water blocking radiation it becomes easier to test the material for beta and alpha contamination.On the Images website we have a number of nuclear experiments and articles. We have an article on testing food for radioactive contamination that goes into greater detail than I can here.I hope this information helps.

Question 2

Will this measure radon in your house?

Accepted Answer

The GCA-07W is sensitive to alpha radiation given off by radon. However this is not the instrument to use to detect or measure Radon in the home. There are specialty instruments and equipment available for just this purpose.

Question 3

Does it have an end sensitive wand?

Accepted Answer

I'm not sure what you mean here. The wand has an open end that exposes the mica window of the GM tube for the detection of alpha particles. In the photograph the wand has a plastic end cap on it that I recommend you keep on unless you are specifically trying to detect alpha particles.  The mica window of the GM tube is thin and easily damaged.

Question 4

Does this unit beep or click? I have seen mixed info. Could someone upload a video of it?

Accepted Answer

That's an interesting question.  The audio output is a tone generator. But that audio output is pulsed quickly so the tone  sounds more like a click than a beep. Technically, they're both right.

ASIN	B000796XSC
Best Sellers Rank	#500,485 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #78 in Lab Geiger Counters
Date First Available	October 1, 2001
Item Weight	1.46 pounds
Item model number	GCA-07W
Manufacturer	Images SI Inc.
Product Dimensions	7.5 x 4.1 x 1.2 inches

Geiger Counter - Digital - Professional - Model # GCA-07W External Wand Probe - ANSI N323A Certification Ready- 0.001 mR/hr Resolution - 1000 mR/hr Range

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