Combination of band-type and line-type emission phosphors with explosive

US3967990A · kind A · utility

Assignee

• The United States of America, as represented by The Secretary of The Interior · US

Inventors

• Frederick M. Ryan · Latrobe, US
• Frank M. Vodoklys · Wayne, US

Key dates

• Filing date: Mar 3, 1975
• Grant date: Jul 6, 1976
• Expiry date: Mar 3, 1995

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S149/123
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

An inorganic fluorescent phosphor consisting of a spotting phosphor and a coding phosphor is employed for tagging purposes, as for example, tagging explosives to provide post detonation information. The spotting phosphor consists of an inorganic fluorescent material which is excited by UV to produce readily detectable band-type emission, but which produces little or no emission at certain excitation wave lengths. The coding phosphor consists of a different inorganic fluorescent material which emits a line-type emission and which fluoresces efficiently at those excitation wave lengths at which the spotting phosphor produces little or no emission. Exemplary spotting phosphors are zinc silicate and calcium silicate activated by manganese, which show no excitation at a UV radiation of 325 nm. Suitable coding phosphors are yttrium vanadate activated by trivalent rare earth ions, such as europium, thulium, erbium, dysprosium or Samarium. This combination of spotters and coding phosphors in cemented phosphor grains employed for tagging purposes enables the quantity of expensive coding phosphors required to be drastically reduced.