Ramachandra K Bhat

US Patent:

49123238, Mar 27, 1990

Filed:

Jan 10, 1989

Appl. No.:

7/295325

Inventors:

Ramachandra K. Bhat - Springfield VA
Janine P. Guadagno - Springfield VA

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01V 500
G01T 1169

US Classification:

2502521

Abstract:

This invention relates to a method for preparing radium-free standard solutions of radon-222-in-water of known concentration for use in the more accurate calibrating of liquid scintillation counters than obtainable by the use of radium-226 as standards for calibration. A radium-free radon-in-water standard of the type contemplated herein is defined as a known volume of deionized water with a known activity of radon gas without the presence of any radium activity. This new method provides for the rapid, accurate and inexpensive analysis of Radon-222 water samples by utilizing standards whose activity is derived from actual instrumental quantitative analysis as opposed to problematical mathematical derivation. Using a glass jar generator apparatus, this method generates with a few days a radium-free radon-222-in-water standard whose concentration is determined by gamma spectroscopy using one sample portion of the standard; and at the same time, using cocktail diluted mixtures of plural sample portions of the same standard to calibrate simultaneously one or several liquid scintillation systems.

US Patent:

48994537, Feb 13, 1990

Filed:

Sep 27, 1988

Appl. No.:

7/249940

Inventors:

Ramachandra K. Bhat - Springfield VA
Janine P. Guadagno - Springfield VA
Clarence E. Duncan - Fredricksburg VA

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01C 1710

US Classification:

33348

Abstract:

A magnetic compass is illuminated by a light emitting diode. The compass is nclosed in a case made of a lightweight, plastic composite material. The light-emitting diode is energized by a low profile, nonmagnetic battery connected to the light emitting diode through a nonmagnetic microswitch operated on the exterior of the casing by a pushbutton. The compass has a compass rose with strips of phosphorescent material disposed thereon, a rotatable bezel with a strip of phosphorescent material thereon and a lid having a sighting slot therein traversed by a cross hair. Located at the bottom and top of the cross hair are additional strips of phosphorescent material so that the compass may be utilized in the dark. The phosphorescent material may be charged by ambient light and by light emitted by the light emitting diode.