Bomb detection sensors

Sensors are often utilized within the field of bomb disposal as a means to locate explosives such as C4. The sensors come in a variety of functions, such as detecting ionized leaks, decorative substances, explosive charges via neutron emission, or, albeit most unreliable, metal

Sensor A
Because explosives of any type often release their own vapor particles via leaks in the sealment of the explosives, a special type of bomb-detecting sensor, called Sensor A, was developed to "sniff out" leaked particle clusters of C4 and other explosives via a method based on ion mobility spectrometry technology. Because of this, their detection is often marked as a cloud on radar to depict the general area of the explosives.

Sensor B
Sensor B is a type of bomb-detecting sensor developed and utilized in the event that the explosives were securely sealed to prevent leaks. Instead of detecting any ionized particles released from the explosives, Sensor B detects the explosives themselves via neutron emission and picking up rear diffusion, due to neutrons interacting with the hydrogen material inside the explosive. When picking up one of the rear diffusions, the sensor will make a ping sound alerting that an explosive is nearby, to which the pings will arrive in shorter intervals the closer it is to the explosive's location.

Usage
During the 2009 Big Shell Incident, Peter Stillman had brought with him some Sensor A units that he intended to supply with SEAL Team 10's Bravo Squad to track down C4 explosives set up by Dead Cell member and former protege Fatman. However, due to SEAL Team 10's demise at the hands of Fortune, he ended up supplying Raiden and Iroquois Pliskin/Solid Snake with two Sensor A devices, along with two Coolant sprays as compensation for the recent lack of manpower in the disposal effort. In addition to the ionized leaks prevalent in the C4 bombs, it was also set up to also detect cologne used by Fatman on his C4 explosives as his modus operandum. Because they were set up to specifically locate Fatman's C4 explosives, they won't detect any C4 explosives planted by either Snake or Raiden. Stillman also spent some time while Snake and Raiden were busy trying to disarm Fatman's C4 explosives building two Sensor B units in Strut C's pantry in case it turned out Fatman had something extra planned, a suspicion that was confirmed later by Pliskin when he stumbled on the C4 charges in Strut H that were both securely sealed and lacked cologne. Raiden later used it to attempt to locate the C4 explosive at the Deep Sea Dock in Strut A after the sealed C4 had been activated due to the decoy C4's deactivation. It only picked up Fatman's C4, namely because it was slightly different from regular C4 due to Fatman adding a large amount of wax.