Nuclear gauges have a radioactive source that is covered by a radiation blocking shield. Gauges can contain a
gamma, beta or neutron radiation source
. Different sources are used depending on what the nuclear gauge is measuring. Radiation from a nuclear gauge does not make the materials it measures radioactive.
What are two types of radiation that the gauge uses to measure density and moisture?
One of the radioactive sources, Cesium 137, emits
gamma ray photon radiation
to determine density, while the other radioactive source, Americium 241 (combined with non-radioactive Beryllium), emits neutron radiation to determine moisture content.
What are the two types of radiation that the gauge used to measure density and moisture?
Gamma, beta and neutron radiation
What is a moisture density gauge?
The Nuclear Moisture Density device (or Nuclear Gauge) is
specifically designed to measure the moisture and density of soils, aggregates, cement, and lime treated materials
, and to measure the density of asphalt concrete.
How does a moisture density gauge work?
The gauge works by
counting the radiation that is received over a given period of time, generally one minute
. So when you push the button to take a test the gauge counts the radiation for one minute and calculates the density based on the depth of measurement.
What is the most penetrating type of radiation?
Gamma rays
have the most penetrating powers of all three radiation sources.
Which type of radiation has no mass?
ELECTROMAGNETIC RADIATION (Gamma rays and X-rays)
has no mass and no charge.
What’s the safest level of radiation?
Adult:
5,000 Millirems
. The current federal occupational limit of exposure per year for an adult (the limit for a worker using radiation) is “as low as reasonably achievable; however, not to exceed 5,000 millirems” above the 300+ millirems of natural sources of radiation and any medical radiation.
Are used in nuclear radiation level indicators?
Nuclear gauges are devices that
use radioactive sources to measure parameters
such as thickness, density, moisture or fill level. Nuclear gauges normally incorporate a nuclear source, a detec- tor and a shutter. Although radiation is being emitted all the time, the shutter can be closed to shield the radiation beam.
What is the average background radiation exposure for a citizen of the United States?
According to the National Council on Radiation Protection and Measurements (NCRP), the average annual radiation dose per person in the U.S. is
6.2 millisieverts (620 millirem)
.
What is ASTM D6938?
ASTM D6938
This
test method describes the procedures for measuring in-place density and moisture of soil and soil-aggregate by use of nuclear equipment
. The density of the material may be measured by direct transmission, backscatter, or backscatter/air-gap ratio methods.
Can compaction be more than 100?
In low water content, the soils are difficult to be compacted. … In case the compaction test results indicate values exceeding 100%, it only means that
the in-situ compaction is more than that being carried out in laboratories
which is treated as the basic criterion for satisfactory degree of soil compaction.
What is the difference between wet density and dry density?
The relationship between dry density and wet density is:
dry density = wet density divide by (1 + moisture content as a fraction)
. e.g., Moisture content is 10%. Wet density is 110 pcf, then the dry density is 110/1.1 = 100 pcf.
What does a Troxler test?
The Troxler Model 3440 gauge can
measure the moisture content, density and percent compaction of soils
, soil-stone aggregates, concrete, asphalt treated bases, asphalt surfacing and other materials that are similar in density and / or moisture content.
Which is the equation of nuclear density?
The usual definition of nuclear density gives for its density:
ρ
nucleus
= m / V = 238 x 1.66 x 10
– 27
/ (1.73 x 10
– 42
) = 2.3 x 10
17
kg/m
3
. Thus, the density of nuclear material is more than 2.10
14
times greater than that of water.
Can you use a nuclear density gauge in the rain?
Do not use the gauge in the rain
.
