News Releases Corporate Profiles

March 1, 2000
Development of the world's most sensitive explosive detection technology
- Instantaneous detection of explosive chemicals in the air -
     Hitachi, Ltd(TSE:6501). announced the development of the world's most sensitive 
detection technology capable of detecting airborne explosive ingredients instantaneously.  
This technology enables real-time detection of the main ingredients of plastic explosives, and 
is expected to pave the way for increasing security in important facilities such as airports and 
electric power plants.
     Currently, two types of detection methods are in main use. The "bulk detection method", 
which uses x-rays to determine the existence of suspicious objects such as knives and firearms, 
from their shapes; and, the "trace detection method", which detects the presence of explosives 
by chemically analyzing the vapor from explosive ingredients.  The combined use of bulk 
detection and trace detection to improve sensitivity, is increasing and becoming more popular.
    Quick detection speed, high sensitivity, and high selectivity to identify the vapor 
generated from explosive substances, are considered important factors in the trace detection 
method.  The technology already exists to detect the presence of the common explosive 
trinitrotoluene (TNT) at room temperature, by analyzing for the presence of vaporized 
explosive ingredients in the air surrounding the object concerned.  However, the main 
ingredient of plastic explosives, RDX*1 or PETN*2, have a vapor pressure about 3 orders of 
magnitude lower than that of TNT.  As such, only a trace amount of the substances exist in a 
vaporized state at room temperature.  Conventional technology requires pre-treatment such 
as condensing the air extracted or increasing the amount of vaporized substance by warming 
the sample.
    The Central Research Laboratory of Hitachi, Ltd. has solved the above issues, and 
developed a high-speed high-sensitivity explosive substance detection technology capable of 
detecting substances such as RDX and PETN which have a low vapor pressure.  The newly 
developed detection technologies have the ability to efficiently ionize a given vaporized 
substance, and the ability to detect the selected substance using mass spectrometry.  With 
this technology, it is now possible to detect by direct air sampling the presence of explosive 
substances which only exist in trace amounts at room temperature without pre-treatment such 
as concentration or heating, and determine the substance.
    This technology is suitable for hand luggage, persons, mail pieces, etc.; situations where 
a large amount of objects need to be inspected quickly.  By combining it with the 
conventional bulk detection method, it is possible to increase security in facilities such as 
airports, customs and power plants.
    The next step is to commence development for practical application, such as decreasing 
equipment size and developing software, as well as consideration into increasing the range of 
dangerous substances detectable (e.g. narcotics).

 Features of the New Technology
(1) Real- time detection without the need for pre-treatment
    Detection is conducted by simply placing the object near the air sampling probe.  Pre-
    treatment such as heating or sample concentration is unnecessary.  The response time 
    after the sample gas is introduced into the analysis chamber is about 0.2 seconds.  If 
    applied to baggage inspection, the total detection time would be about 1-2 seconds, even 
    taking into account the gas introduction time.
(2) Highly sensitive detection by using a newly developed ion source  
    A new design ion source was developed to efficiently ionize explosive substances.  By 
    creating a counter flow between the direction of the gas extracted and the ion flow, 
    neutral substances which interfere with the ionization reaction were removed from the 
    ionization region.  By detecting the ions created, it is possible to detect trace amounts of 
    explosive substances adhering to body or clothing, and to successfully detect the presence 
    of RDX or PETN at room temperature for the first time in the world.
(3) Highly selective detection for identifying explosives
    In order to identify explosives from the wide range of chemical substances present in the 
    atmosphere, mass spectrometry technology, with an outstanding ability to identify 
    substances, was applied in the detection region.  In particular, by employing the "multi-
    stage mass spectrometry"*4 function of the 3D quadrupole mass spectrometer*3 used in the 
    analysis of organic substances, the error rate was kept at an extremely low level. 

< Explanation of Terms>
(*1) RDX¡§Hexogen ¡Ê1,3,5-Trinitrohexahydro-1,3,5-triazine¡Ë
(*2) PETN¡§Pentaerythritol Tetranitrate
(*3) Three-dimensional quadrupole mass spectrometer: A quadrupole ion-trap type mass 
     spectrometer consisting of a ring electrode and two endcap electrodes.
(*4) Multi-stage mass spectrometry: To improve selectivity, fragment ions dissociated from 
     pre-determined mass ions can be analyzed.

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