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If an instrument becomes inoperable due to failure, overload or expendable supply replacement the test coordinator must be notified before corrective action is taken. A maximum of 30 minutes is permitted after which time the instrument will be removed form the test phase

and allowed to clear. The sampling can continue at a late point. The event will be recorded by the scorer/observer.

Repeated failure or overload which appears to seriously threaten the time schedule may result in the instrument being declared inoperable by the referee for the remainder of the test phase.

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ITI Comments on the FBI Explosives Detector
Evaluation

1. We would point out that the devised test scenarios were of the "response" type as opposed to routine screening operations. WE feel it would have been instructive to engineer a security checkpoint scenario in which the operator would have a chance to obtain vapor from inside the cases/packages. It is common practice in checkpoint applications to set conditions and employ techniques to enhance detection. For example it would have been useful to show the benefits of some of the techniques used to extract vapor from packages. These include non-contact thermal pumping (raising the package temperature rapidly by the use of a high powered light), burping of flexing the package to expel air and penetration of the barrier with needle probes. Also the atmosphere in the vicinity of the test would not be heavily contaminated with both halogens and nitro compounds.

2. The results of sniffing Semtex explosive were not reported because it has been assumed that the explosive sample had been contaminated by EGDN. our tests with the Model 97 showed that the Semtex has a very volatile nitro compound in the headspace vapor which is easy to detect this vapor was shown to be DIFFERENT for EGDN .

3. Internationally based terrorist organizations use ANPO and SEMTEX. Inclusion of these materials would have been more typical of the threat faced by some of the Government Agencies.

4. We would like to take the opportunity to point out the difference between discontinuous sampling devices and continuous sniffing devices. The Model 97 is a continuous sniffing device which will continue to operate in a contaminated background as was demonstrated during the first morning of the trials. The contaminated background, however, may have impaired the effective sensitivity of the instrument.

5. Contaminated backgrounds and hang-up from previous tests causes false positive in batch sampling detection systems. For this reason with this type of instrument, blank samples should be taken after each positive detection until no response is achieved. Unfortunately, no blanks were taken after detecting the pure explosives during the preliminary trials. consequently, the results form the preliminary test on the pure explosives may be misleading.

II.

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MARYLAND STATE POLICE AT BALTIMORE WASHINGTON INTERNATIONAL

On January 28, 1987, the field test of two explosive detectors took place. Equipment tested was the Model 97 from ITI and the Scintrex EVD-1. Personnel participating in the evaluation were: Captain Larry E. Harmel, Comdr., MSP Airport Division; Lt. Robert L. McWhorter, Assist. Comdr., Airport Division; Sergeant Kenneth Chartrand; Tfc. Ronald Price; Deputy Chief Allen L. Ward and Deputy Fire Marshall Richard G. Labrocco.

The test consisted of searches aboard aircraft, on the tarmac and of motor vehicles. Additional searches were conducted inside the terminal building and included those of pay lockers and hold room (pre-board) areas.

Continental Airlines Manager, Orlando Berry, provided a DC-8 aircraft for the exercise. Due to the short term availability of the aircraft, both the Model 97 and the EVD-1 were evaluated alternately. About a half a dozen bags were placed in the first class seats and overhead baggage area. One of these bags contained sheet explosive and another contained detonator cord.

Tfc. R. E. price searched the aircraft first with the Model 976 and then the EVD-1. The searches were monitored by Deputy Chief Ward, who recorded the results for each machine. Following the on-board search activity an attempt to detect the explosives by sampling air discharged through the "dump valve" was made. This entailed sampling air discharged for the aircraft at an external port (dump valve).

Other bags had been lined up on the tarmac, one of which contained C-4 explosive and another TNT. Again each bag was scanned by TfG. Price using the Model 97 and by Sgt. K. Chartrand using the EVD-1.

The Evaluation Committee found the Scintrex EVD-1 to be unsuitable for its intended use at BWI Airport. This is due to the inherent operational limitations of the equipment. While as reliable as the ITI Model 97, it was found to be too slow since it is a sample and analyze type instrument. It was subject to human error and to require manpower resources for operation which are not feasible.

The Model 97 was found reliable under a wide variety of conditions. It is fully portable and can be deployed upon short notice by a single operator. Operation is simple enough to permit all police personnel to operate it with minimal training.

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The Model 97 renders immediate analysis since it is a continuous testing instrument. This permits the searching of a large number of articles within a relatively short time. It enables the operator to identify the specific article, area, etc., emitting the suspect vapor, thus eliminating confusion and additional hand searches.

The Evaluation Committee concurred that continuous screening is an essential capability of any explosive detections equipment and was unanimous in its findings and recommendations of the Ion Track Instruments, Inc., Model 97 explosive detector for deployment at BWI Airport.

other tests have been conducted for the detection capabilities of the Model 97 by organizations such as Aramco Oil Corporation of Houston, British Petroleum and Stone and Webster Engineering. These particular test haven't been presently released. All of the above have reported excellent results for the Model 97 and 85.

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