Trace detection methods
In IMS, ions are separated in a ____________
Drift tube
The predominant form screening for both mail and luggage in the 1970s
X-ray
A collection of VOCs attributed to a given sample is called its ____________
Vapor profile / vapor signature
Device that converts chemical interaction in a measurable signal
Chemical sensor
"C" in SWaP-C standards for this.
Cost
For portable mass spectrometers to be practical for use outside of the laboratory, they commonly use this ionization method (category)
X-ray backscatter technology
Millimeter-wave technology
Two reasons vapor detection is difficult in security settings.
low abundance of analyses (low vapor pressures); background requires high selectivity, dilution and unpredictable airflow producing uncertain vapor plumes; concealment tactics
Measures the change in electrical resistance of a heated metal oxide
MOX (metal oxide semiconductor) sensors
What decade were canines were deployed for threat detection in the U.S.?
1970s
Why are sampling wands are used in trace particle sampling as opposed to swabbing by hand?
Improves consistency between individuals
The most important step in the process of vapor detection
Sampling / pre concentration / vapor transport
Series of sensors that produce a pattern of responses
Sensor array / e-nose
Figure-of-merit that expresses a system's ability to separate two peaks with drift times t1 and t2 and peak widths w1 and w2
Resolving power / resolution
3-D Computed Tomography (CT)
If you consider a detection dog a whole animal biosensor, then what are the sensors / sensing apparatus (hint. also exploited in other human-made biosensors)
olfactory receptors
Two main components of a chemical sensor
What primary feature of potassium chlorate, a common HME component, makes it difficult to detect by IMS?
low / no vapor pressure
Colorimetric test used for identification of cocaine
Scott's test
Coefficient that is proportional to a material's density and atomic number
x-ray attenuation coefficient
Mechanism for training a dog to follow a person-borne explosive device
Vapor Wake
Advantage of a biosensor that is unique compared to other types of sensors
Extremely high selectivity (specificity)
Also, can detect living organisms or biological molecules
Plot of False Alarm Rate vs Probability of Detection
Receiver Operator Characteristic (ROC) curves