The detector in "Stalker 2: Heart of Chernobyl" is a special prop used to find various things in the game. If you want to get a detector, you can buy it from the vendor NPC in the settlement. For example, like bear detectors, echo detectors are built-in by default.
How to get the Chernobyl Heart Detector in S.T.A.L.K.E.
The echo detector is a device available by default in the early stages of the campaign. It can be used to find prehistoric artifacts in abnormal areas. It is not difficult to obtain other detectors. Later, you can purchase more advanced equipment, such as bear detectors, from unknown settlements.