NCJ Number
58402
Date Published
1978
Length
8 pages
Annotation
RESULTS OF A LABORATORY STUDY ON THE FEASIBILITY OF DETECTING EXPLOSIVES VIA THERMAL NEUTRON ACTIVATION ANALYSIS ARE DISCUSSED IN THIS ARTICLE.
Abstract
THE STRUCTURE OF THE SYSTEM CONSISTED OF A 1-INCH POLYETHYLENE CAVITY SHELL SURROUNDED BY PARAFFIN. THE SIX DETECTORS USED IN THE STUDY WERE 2-INCH-WIDE AND 10-INCH-LONG NE102 PLASTIC SCINTILLATOR CYLINDERS COUPLED TO PHOTOMULTIPLIER TUBES. AFTER THE EXPLOSIVE OR NITROGENOUS MATERIAL WAS POSITIONED IN THE SUITCASE, THE SUITCASE WAS INSERTED INTO THE CAVITY ON TOP OF THE LOCATING BOARD. AT EACH OF 16 SEQUENTIAL POSITIONS, THE DATA NUMBERS FROM THE 6 SCALERS WERE TYPED INTO A TELETYPE WHICH WAS THEN READ INTO A PDP-11E/10 COMPUTER. THE EXPLOSIVE DETECTION ASSESSMENT TEST WAS BASED ON 12 TESTS. IN THE TESTS DESIGNED TO MEASURE THE SYSTEM'S CAPACITY TO DETECT EXPLOSIVES ALONE IN BAGGAGE, IT WAS FOUND THAT IT WAS POSSIBLE TO 'SEE' AN IMAGE OF THESE EXPLOSIVES WITHIN AN EMPTY SUITCASE. TESTS WERE THEN RUN TO SEE IF THE SYSTEM WOULD SEND OUT A FALSE ALARM FOR MATERIALS WITH A HIGH NITROGEN CONTENT SUCH AS LEATHER SHOES. APPLICATION OF PATTERN RECOGNITION TECHNIQUES CAN SIGNIFICANTLY REDUCE FALSE ALARMS FROM LUGGAGE CONTAINING LARGE QUANTITIES OF NITROGENOUS ITEMS. THIS SYSTEM CAN MEET THE FEDERAL AVIATION ADMINISTRATION REQUIREMENT OF A BAG PROCESSING RATE OF 10 PER MINUTE. PHOTOGRAPHS, ILLUSTRATIONS, AND STATISTICAL TABLES PRESENTING TEST DATA ARE PROVIDED. (KCP)