Radiation

Radiation are particles or waves emitted by a radioactive source.
There are more types of radiation:
Electromagnetic radiation includes radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma radiation.
Particle radiation includes alpha radiation (formed by 2 protons and 2 neutrons, same as a helium atom but without electrons), beta radiation (electrons or positrons), neutron radiation.

Radiation is ether ionizing or non-ionizing, depending on its energy.
Ionizing radiation carries more than 10 eV and can ionize atoms breaking their chemical bonds.

Ionizing radiation comes from sources that decay, because they contain unstable isotopes of an element; thorite or uranite are examples of minerals which contains thorium and respectively uranium that decay over time, emitting radiation.

Ionizing radiation is measured in dose (gray (Gy) or sievert (Sv) ) or particle counts (per seconds (cps) or per minute (cpm) ).

In 1896, Henri Becquerel found that rays emanating from some minerals penetrate black paper and cause fogging of unexposed photographic plate.
His doctoral student Marie Curie discovered that only certain chemical elements gave off these rays of energy, and she named this behavior radioactivity.

When radioactive emits radiation, they decay in other elements, losing neutrons and protons.
Unstable elements are called radioactive isotopes or radioisotopes or radionuclides.

Any element is made from protons, the number of protons dictates which element it is.
Neutrons are there to make the atom stable, or as stable as possibly can be.
With the higher number of protons and neutrons, an element becomes more unstable because is getting heavier and harder to keep its structure.
The number of neutrons define a isotope.
Hydrogen can have several isotopes.
Having one protons defines it as being hydrogen, because it has just one positive charge (proton), a neutron is not in need, just an electron will do the job.
But adding neutrons will still make stable isotopes.
A hydrogen atom with zero neutrons is called protium, isotope H 1
A hydrogen atom with one neutron will be named deuterium, isotope H 2 and a hydrogen atom with 2 neutrons will be called tritium, isotope H 3 but will be unstable, with a half-life of 12,32 years.

Half-life is the time required for an unstable element to decay half of its initial value.
So a tritium atom (Hydrogen isotope 3) will have a half-life of 12,32 years, which means in 12,32 years, from a gram of tritium, half of it (0,5 grams) will not be tritium anymore, but helium 3.
When an atom decays, its releases energy in form of radiation and a product.
Hydrogen 3 (tritium) will emits beta minus particles and as a product will be helium 3.
As helium 3 is stable, it will not decay further.

Ionizing radiation:

• Ultraviolet radiation: wavelength between 10 nm to 125 nm, ionizes air molecules and are absorbed by air and ozone (O3) and is sometimes referred as vacuum ultraviolet because is present in space. Can damage biological molecules and its DNA.
• X-ray: causes atoms to ionize when an x-ray photon collides with an atom. Large atoms are more likely to absorb an x-ray photon and become more energetic, rather than knocking its electron, thus tissue with more density can be easily identified on a x-ray scan.
• Gamma radiation: process that occurs in unstable nucleus of excess energy. because of its higher energy and having no mass or electric charge (like alpha or beta particles), gamma will penetrate further through matter and only stop by sufficiently thick or dense material, where the stopping power depends mostly on total mass. The atmosphere absorbs all gamma ray so even the air is capable of absorbing, being thick enough.
• Alpha radiation: particles of helium 4 without electrons, interact with matter strongly due to their charge, mass and velocities, penetrating a few centimeters of air or a few millimeters of low density material. Alpha particles does not penetrate further then the skin but it presents danger if is ingested or inhale. Can also be identified as simbol 4 He ++
  The alpha decay is mediated by the strong force.
• Beta radiation: Beta minus consists of energetic electrons, with a more penetrating power than alpha radiation but less then gamma. Can be stopped by a few centimeters of plastic or a few millimeters of metal. It occurs when a neutron decay into a proton, an electron and an electronic anti-neutrino (antiparticle of neutrino).
  neutron -> proton + electron + anti-neutrino
  Beta plus radiation consists of the emission of positrons (antimatter form of electrons), when a positron slows to speeds of electrons in a material, the positron will annihilate an electron, releasing two gamma photons of 511 keV in the process; those two gamma photons will be traveling in the opposite direction.
  In beta plus decay, one proton interacts with an electronic antineutrino to give a neutron and a positron.
  proton + anti-neutrino -> neutron + anti-electrons (positrons)
  The beta decay is mediated by the weak force.
• Neutron radiation: are categorized according to their speed/energy; it consists of free neutrons, emitted during spontaneous or induced nuclear fission.
  Neutron radiation is the only type of ionizing radiation that can make other objects radioactive, process called neutron activation, primary used to produce radioactive sources for medical, academic or industrial applications.

Radiation path can be modified by a magnet for alpha radiation and stronger with beta radiation.
For alpha radiation, magnetism can modify its path up to 45 degree and for beta radiation up to 75 degree, much better curves than alpha radiation.
For gamma radiation, lenses should do it.

Radiation sources:

• gamma-ray bursts and supernovae are sources of photon radiation
• Elements: Technetium, Prometheum, cesium 137, strontium 90, sodium 22 and all the elements starting with Polonium (ex Uranium, Thorium, Neptunium, Radium, Americium etc) and other unstable isotopes

Radioactive minerals:

• Uraninite
• Thorianite
• Grayite
• Torbenite
• Metatorbenite
• Autunite - has light-green fluorescence under UV
• Uranocircite - has light-green fluorescence under UV
• Fuchsite and Muscovite (Micas) - radioactivity due to potassium content but is barely detectable
• Apatite - often contains uranium and may be very low radioactive

Radiation sources easy to find:

• Food and any substances containing potassium: Brazil nuts, bananas, carrots, beans, potatoes, meat, beer and even your body has potassium; because 0,012% of potassium is an unstable isotope, potassium 40 and emits beta particles.
• Smoke detectors have americium 241 which is an alpha emitter.
• Dishes and glass made with uranium for it's color, can be orange opaque or transparent and fluorescent yellow/green used in the past before it was known to be radioactive. (FiestaWare)
• Thorium lanterns and lamps was used in the past.
• Radium watches used the element radium to make the phosphorescent paint glow all the time for several years with the brightest color in the first 10 years.
• Tungsten-thoriated welding rods containing up to 4 percent of thorium.
• Thoriated-tungsten cathode of a microwave oven magnetron.
• Fluorescent lamp starter can contain krypton 85 (that emits beta particles and 0,41 chance of gamma ray), promethium 147 (used for coating the fluorescent tubes and emits beta particles and which just 2,62 years half-life) and tritium H-3 (beta emitter with half-life of 12,3 years) in very small amounts.
• Old glass lenses contains thorium.
• Bentonite, a mineral found in organic kitty boxes which contains traces of uranium and thorium
• Green signs / emergency exit signs contains tritium, Hydrogen 3 that emits beta particles and has a half-life of 12,3 years
• Granite can contains uranium and thorium traces.

Radiation detection:

• CMOS sensor of a webcamera or any digital camera can be used to detect alpha and beta radiation; when a photodiode is hit by a particle, produces a signal and is detected by the hardware.
  The camera must be modified, everything in front of the sensor (lenses) must be removed because glass absorbs alpha particles.
  Alpha particles is high to low in detection, beta particles are detected at a high rate while gamma radiation has a very low rate of detection, the lower is the energy of the gamma ray, the higher chance of detection.
  Cosmic rays are 100% detected as they are made of high energy muons.
  The camera must be covered with a aluminum sheet to cover any light that could enter the sensor.
  To detect the radiation, a software with long exposure time will make the radiation visible when present in high quantities, in this way every radiation detection as a white pixel will remain and not be erased, accumulating frame by frame.
  Usualy pointers means alpha or gamma radiation and lines or curves means beta particles.
• Cloud chamber can be used to detect alpha and beta radiation by using cold alcohol vapors in a closed chamber with a temperature difference of cold on the bottom and warm at the top.
• Spinthariscope - is a device made of a lens, a phosphorescent material and a radioactive material.
  The lense is conected to a tube, in the middle of the tube should be a sheet of phosphor (scintilation screen - zinc sulfate activated) and at the end is a radioactive material.
  When the radioactive material decays, alpha particles will hit and make the phosphor emit light and glow for several seconds, a lens will magnify the points that glows to make it visible.
• Geiger counter - is an instrument that detects ionizing radiation.
  It is made of a tube filled with an inert gas like helium, neon or argon at low pressure and a high voltage is applired to two metals, the center rod and the tube (made of metal), both of them should not touch.
  The tube has a window, when a ionizing radiation passes the window and hits the inert gas, it will make it conductive and for a period of time, the metal parts will conduct electricity and a sound will be made by the speaker to indicate the hit.
  The Geiger counter is limited by death time, in which the Geiger counter cant measure.
• Scintillation counter

Other words: radioactive isotopes radioisotopes radionuclides