Thermal luminescence sensor for ground-path contamination detection.
A standoff method of detecting liquids on terrestrial and synthetic landscapes is presented. The interstitial liquid layers are identified through their unique molecular vibration modes in the 7.14-14.29-microm middle infrared (fingerprint) region of liberated thermal luminescence. Several seconds of 2.45-GHz beam exposure at 1.5 W cm(-1) is sufficient for detecting polydimethyl siloxane lightly wetting the soil through its fundamental Si-CH3 and Si-O-Si stretching modes in the fingerprint region. A detection window of thermal opportunity opens as the surface attains maximum thermal gradient following irradiation by the microwave beam. The contaminant is revealed inside this window by means of a simple difference-spectrum measurement. Our goal is to reduce the time needed for optimum detection of the contaminant's thermal spectrum to a subsecond exposure from a limited intensity beam.
Carrieri
A H
AH
U.S. Army Soldier and Biological Chemical Command, Edgewood Chemical Biological Center, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010-5424, USA. arthur.carrieri@sbccom.apgea.army.mil
Barditch
I F
IF
Owens
D J
DJ
Roese
E S
ES
Lim
P I
PI
Talbard
M V
MV