Cold molecular clouds as cosmic ray detectors

The ionization of the neutral gas in an interstellar molecular cloud plays a key role in the cloud's evolution, helping to regulate the heating and cooling processes, the chemistry and molecule formation, and coupling the ...

New CubeSat will observe the remnants of massive supernovas

Scientists at CU Boulder are developing a satellite about the size of a toaster oven to explore one of the cosmos' most fundamental mysteries: How did radiation from stars punch its way out of the first galaxies to fundamentally ...

Chemotherapy drugs react differently to radiation while in water

Cancer treatment often involves a combination of chemotherapy and radiotherapy. Chemotherapy uses medication to stop cancer cells reproducing, but the medication affects the entire body. Radiotherapy uses radiation to kill ...

What ionized the universe?

The sparsely distributed hot gas that exists in the space between galaxies, the intergalactic medium, is ionized. The question is, how? Astronomers know that once the early universe expanded and cooled enough, hydrogen (its ...

Lightning produces afterglow of gamma radiation

Lightning can produce X-rays and gamma radiation. In the past, researchers thought that this phenomenon only lasted for a very short time, about one ten-thousandth of a second. However, the ionizing radiation of lightning ...

Explaining why the universe can be transparent

Two papers published by an assistant professor at the University of California, Riverside and several collaborators explain why the universe has enough energy to become transparent.

Chernobyl, three decades on

It was 30 years ago that a meltdown at the V. I. Lenin Nuclear Power Station in the former Soviet Union released radioactive contaminants into the surroundings in northern Ukraine. Airborne contamination from what is now ...

page 1 from 6

Ionizing radiation

Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach electrons from atoms or molecules, ionizing them. The occurrence of ionization depends on the energy of the impinging individual particles or waves, and not on their number. An intense flood of particles or waves will not cause ionization if these particles or waves do not carry enough energy to be ionizing. Roughly speaking, particles or photons with energies above a few electron volts (eV) are ionizing.

Examples of ionizing particles are energetic alpha particles, beta particles, and neutrons. The ability of electromagnetic waves (photons) to ionize an atom or molecule depends on their wavelength. Radiation on the short wavelength end of the electromagnetic spectrum - ultraviolet, x-rays, and gamma rays - is ionizing.

Ionizing radiation comes from radioactive materials, x-ray tubes, particle accelerators, and is present in the environment. It is invisible and undetectable by human senses, so instruments such as geiger counters are required to detect its presence. It has many practical uses in medicine, research, construction, and other areas, but presents a health hazard if used improperly. Exposure to radiation causes microscopic damage to living tissue, resulting in skin burns, radiation sickness and death at high doses and cancer, tumors and genetic damage at low doses.

This text uses material from Wikipedia, licensed under CC BY-SA