1. A stable elementary particle of the baryon family that is a component of all atomic nuclei and carries a positive charge equal to that of the electron's negative charge.
2. The number of protons in the nucleus of an atom equals the atomic number of the element.
3. An elementary particle having a single positive electrical charge and constituting the nucleus of the ordinary hydrogen atom.

The positive charge of the nucleus of any atom is due to its protons. Every atomic nucleus contains one or more protons; the number of protons, called the atomic number, is different for every element.

A particle accelerator which accelerates protons to high energies, as opposed to one which accelerates heavier ions or electrons.

A measure of proton concentration, or the number of atomic nuclei for given volumes.

It is one of the major determinants of magnetic resonance signal strength in hydrogen imaging.

1. A device used in subsurface detection which records variation in the earth's magnetic field.
2. An instrument used in magnetic surveying for detecting changes in magnetic field intensity.

It takes intermittent measurements of absolute field strength.

3. A sensitive device designed to measure the frequency of the proton resonance in ordinary water.

1. A powerful type of microscope that uses a beam of protons, giving high resolution and sharp contrast.
2. An instrument that uses protons instead of electrons to form the image of minute or tiny objects for viewing.

1. A drug that limits acid secretion in the stomach.
2. Any of a group of drugs that inhibit the activity of proton pumps and are used to restrain gastric acid secretion in the treatment of ulcers and gastroesophageal reflux disease.
3. Any of a group of drugs used to treat excessive secretion of acid in the stomach and any resulting ulcers.

They block the enzyme (proton pump) in the cells of the gastric glands that secrete hydrochloric acid.

1. A ring-shaped synchrotron that accelerates protons to energies of several billion electron volts.
2. A circular, very high-energy particle accelerator that accelerates protons through the action of magnetic fields and a high-frequency electric field.

1. Treatment in which doctors use nuclear technology and magnets to fire protons into tumors at about two thirds the speed of light.

Proton therapy's promise lies in its ability to destroy cancerous cells while sparing healthy cells half a millimeter away, reducing side effects. It also allows doctors to ramp up the radiation dose, theoretically improving cure rates.

The precise targeting is possible because the subatomic particles release the bulk of their destructive energy beneath the skin, at the tumor's depth, rather than near the surface, as X-rays do; and while standard radiation tends to cause damage to healthy tissues on the far side of tumor, protons slow and stop as they release their energy pulse, eliminating a harmful exit dose.

2. A precise form of radiation treatment for cancer and other conditions.

It is said to minimize damage to healthy tissue and surrounding organs, and such proton treatment is considered to be highly successful and it results in fewer side effects.