X-ray inspection is commonly used for security screening of baggage, such as checked and carry-on luggage. The core system consists of x ray source, L shape photo detectors and software. They’re used to build a picture of what’s inside baggage and allow security staff to check anything that looks suspicious. 

X-rays launched from one side of the machine are picked up by a pair of detectors on the opposite side. As your bag enters through the lead-lined curtains, it crosses the path of these X-rays and absorbs some of the energy they carry. This means that the X-rays that passed through the baggage have less energy than those that sailed straight past.