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Using Geiger Counter Measurements and things to know #5-1

TCharley300

Well-known member
Think of a Geiger counter like the old canary in the coalmine. Meaning, if the canary died or passed out, it’s time to head to the surface for air. Well, the Geiger counter is somewhat of the same way, except it’s to let you know about Gamma radiation and Beta particles in your area.

Radiation:: You can’t see it---You can’t smell it----You can’t taste it. Only one exception you can at least taste ionized particles, because it will have a metallic taste. But honestly, if you can taste it, more than likely you will die fairly soon from radiation poisoning. It takes an extremely high dosage of radiation to ionize particles.

So, your Geiger counter is your ‘sniffer’ and taster in this respect.

I’m going to start off with the “old school” Geiger counters, because I’ve used them many times in the past and have come to rely upon them versus the newer models.

The old models used a measurement called Rads. You’ll also hear the term Rems. Both rads and rems are basically the same thing, and the calculations are basically the same—one to one for ease of figuring. Although this is an opinion basis on my part, I think that the many different terms used with radiation are deliberately used to confuse the public. Currently, at least in the past 10-20 years, the term sievert is most commonly used, and that one is very easy to screw up in your mind. The sievert measurements are supposed to be designed to be more accurate. (yea right) Sure, it would be more accurate as far as trying to read the digital readout versus an analog gauge, and it can go in smaller numbers, but really, that’s about it.

Now, to understand measuring radiation, there are basically 4 areas, but for ease and importance of learning, only two, which are the most important will be represented.

This is not complete and not intended to be complete. I’m just trying to give information as easily as possible for the ‘man on the street’.

Think of the term read or R E A D

R is radioactivity. Radioactivity refers to the amount of ionizing radiation released by a material. Whether it emits alpha or beta particles, gamma rays, x-rays, or neutrons, a quantity of radioactive material is expressed in terms of its radioactivity (or simply its activity), which represents how many atoms in the material decay in a given time period. The units of measure for radioactivity are the curie (Ci) and becquerel (Bq). ( Don’t worry about the curie and Becquerel)

E is the exposure. Exposure describes the amount of radiation traveling through the air. Many radiation monitors measure exposure. The units for exposure are the roentgen (R) and coulomb/kilogram (C/kg).

A is the amount absorbed by the body Absorbed dose describes the amount of radiation absorbed by an object or person (that is, the amount of energy that radioactive sources deposit in materials through which they pass). The unit measurement for absorbed doses are the radiation absorbed dose (rad) and gray (Gy).

  • D is the dosage equivalent Dose equivalent (or effective dose) combines the amount of radiation absorbed and the medical effects of that type of radiation. For beta and gamma radiation, the dose equivalent is the same as the absorbed dose. By contrast, the dose equivalent is larger than the absorbed dose for alpha and neutron radiation, because these types of radiation are more damaging to the human body. Units for the dose equivalent are the roentgen equivalent for man (rem) and sievert , which is (Sv) and biological dose equivalents are commonly measured in 1/1000th of a rem (known as a millirem or what is called mrem
Confused yet?????

For practical purposes, 1 R (exposure) = 1 rad (absorbed dose) = 1 rem or 1000 mrem (dose equivalent-- Or sievert.

Now, we will only deal with rads (which is also rems) and M rems (or 1,000th of a rad or rem) Think of it this way for ease of figuring. Take the Rad measurement, multiply by 10 first, put your decimal point to the right of that number and add 2 zeros to get the mili sievert. (1X10=10) put the decimal point at the new figure (10.) then add 2 zeros 10.00 Your new answer is 10.00 mili sievert. So, 1 rad = 10 milli sieverts.

I’ll use the Chernobyl movie as an example The first reading stated was 3.6 rem. OK, take the 3.6, multiply by 10 which equals 36 put the decimal at the last number on the right, THEN ADD 2 zeros. You now have 36 mili sieverts. Movie said “not great not terrible” Which if you look at the OSHA chart below, you’ll find the statement to be true.

This is why I say that when folks here the word milli, and micro it automatically puts their mind at ease. (thinking it’s a real small number)

The problem is that those real small numbers can kill you.

For the old school bunch that are used to rads or rems---to convert to mili sievert take your number multiply by 10. Put the decimal point at the last number and add 2 zeros to the right.

To convert mili sievert to rads or rems, place the decimal point one space to the left, Then add one zero to the right.



I don’t know how to make it any simpler than that.

I’m not even going to go with the sievert route, because 1 sievert or above is over a 50% fatality rate in a period of close to 30 days. The maximum readings on a Terra-P dosimeter is 999 mili sieverts.

Western Kentucky University, which is an applied science university uses the following figures for radiation exposure. This is their radiation safety training sector, probably for x-ray techs, MRI, CT scan, etc.

Annual Maximal

Permissible Dose

5,000 mili rem or 5 rem 50 mili sieverts (0.05 sieverts) Whole Body Deep Dose equivalent

100 mili rem or (0.1) rem a year 1 mili sievert or 0.001 sievert a year This is the gen public

I placed those figures above to just show what a huge difference there was with radiation workers and the general public. For the sake of a nuclear detonation, the charts from OSHA makes much more general sense.

The graph below comes from OSHA It’s the easiest one to understand

1642378302792.png



Now, let’s put this stuff together and make sense of everything.

Which is better? 1 Severt or 100 rads? If the radio broadcaster said that a reading of 1 sievert was in the area, how would you feel? Would you feel safe? Or if the broadcaster said that a reading of 100 rems or rads was in the area, how would you feel? Answer that question to yourself. Oh, by the way, the readings are the same, which is a potentially lethal dose. See the deception to the general public that doesn’t know any better? This is exactly why I think old school is the best.

Let’s put this new knowledge to work. And yes, some mathematics is involved.

We’ve had a detonation and the reading is 2 rads per hour. (remember the total of 100 is tops to survive) Now—that tops is cumulative, so there’s no subtraction. If you’re caught outside and can’t get to shelter, you’re getting 2 rads EVERY HOUR. So, if you’re stuck outside for 24 hrs—That’s a total of 48 rads or rems. Let’s round it up to 50 to make things easy. That’s day one. If your still caught outside on that 2nd day, you’ve gotten another 48 rads. So, round it up a tad to 50. Well, there’s your dose right there all accumulated up in only 2 days. Day 3-??? There’s a 50% or more chance you’re gonna die a horrible death.

So, you have one of the newer Terra-P type. They read in Sieverts. (which I personally despise)

Their display shows either mili sieverts which is a small m then a space then sv and it doesn’t show per hour, it only shows the total exposure for the time period. The main display shows micro sieverts, which is a funny looking U with a stem off the left side of the U and then the S for sieverts and then the / sign showing per hour. The unit automatically defaults at 30 micro sieverts per hour, sounding an alarm. Let’s use 30 as an example. The alarm is sounding . Rounding up from 48 rads in a day to 50 for ease of figuring equals 500 mili sieverts That’ day one Day two same readings, but now the body has absorbed 1000 mili sieverts or 1 sievert.

(Borderline death) Day three same readings you’re a gonner.
 
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