Transillumination of the subsurface and cavity detection

摘要

#$%^&*AU2019203737A120200116.pdf#####Abstract In a method for generating a transillumination signal (28a to 28c) of a section (22) of the subsurface (2), an HPEM radiation source (14) radiates an electromagnetic pulse (20) into the section (22) for the purpose of exciting electromagnetically reactive structures (12) to emit an electromagnetic response signal (24), wherein, for the pulse 5 (20), a pulse duration of at most 500 ns, and a centre frequency in the range between 10 MHz and 10 GHz, and a bandwidth in the range from 10% to 150% of the centre frequency has, and the transillumination signal (28a to 28c) is formed as the sum of response signals (24) received at a measuring location (Ma to Mc). 10 In a method for detecting a cavity (HR) in the subsurface (2), the above method is carried out, and the structures (12) are detected from the transillumination signal (28a to 28c) with the aid of a detection method (DV), and the cavity (HR) is detected if the structures (12) satisfy a detection criterion (DK). 15 A detection arrangement (30) having the HPEM radiation source (14) contains a receiver (26a to 26c) for the response signals (24). An HPEM radiation source (14) is used to carry out the methods/in the detection arrangement (30). 20 (Figure 1)1/4 ~04 £ crO co Co1 CoN 00oC Q4 CNN