The 5 yen coin is one denomination of Japanese yen. A 1,000 yen note, featuring the portrait of Natsume Soseki. ...

Following the Tokaimura nuclear accident, physicists Masuchika Konho and Yoshnobu Koizumi showed how this coin could be used to estimate neutron dosage to the surrounding population, by measuring its zinc isotope ratios. They write: The word physicist should not be confused with physician, which means medical doctor. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... Isotopes are forms of a chemical element whose nuclei have the same atomic number, Z, but different atomic masses, A. The word isotope, meaning at the same place, comes from the fact that all isotopes of an element are located at the same place on the periodic table. ...

The Japanese 5-yen coin is about 22 millimeters in diameter and 1.5 mm thick, weighs 3.75 grams and has a central hole 5 mm wide. We chose this coin for monitoring neutron exposure because it is widely circulated, the zinc content is precisely controlled, and the ⁶⁵Zn generated has a convenient half-life (244.1 days) and gamma ray energy emission (1,115.5 keV). To obtain a record of the dosage of neutrons released as a result of the accident, we collected exposed coins from people's houses at distances 100–550 m from the facility.

(Nature 406, 693 (2000); doi:10.1038/35021138)

They concluded that the coin could offer information about the total neutron effect during the accident, and about shielding by modern Japanese houses, given that the coins were recovered from indoors. 1¢ euro coin A coin is usually a piece of hard material, generally metal and usually in the shape of a disc, which is used as a form of money. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... For the geometric term, see diameter. ... The gram or gramme, symbol g, is a unit of mass, and is defined in the SI system of units as one one-thousandth of a kilogram (i. ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... This article is about electromagnetic radiation. ... Wikipedia does not yet have an article with this exact name. ... Nature is one of the oldest and most reputable general-purpose scientific journals, first published on November 4, 1869. ...

See also

• List of nuclear accidents

Pathways from airborne radioactive contamination to man This is a list of notable accidents involving nuclear material. ...

External links

• The front sides of two five yen coins.
• The back sides of two five yen coins. The coin on the right was shrunk with a very strong magnetic field by an amateur scientist in the United States (unrelated to nuclear power).