The vertical distance between the x ray grid gate planeand the focus is called gate focal length.
Each x ray grid has its own grating focal length. Photographing at this distance will not cause significant loss of the primary ray. It also gives a range of accommodation of the photographic distance, which decreases with the increase of the grating ratio.
Chest photography and head or lumbar photography can not use the same focal length x ray grid. Because the photographic distance of the chest is 180cm, and the photographic distance between the head and the lumbar vertebrae is 100 to 120cm.
Author：X Ray Grids Maker
Tel: +86 536-8882360
Company: Weifang Newheek Electronic Tech Co., Ltd.
Address: E Building of Future Star Scientific Innovation Industrial Zone of No.957 Wolong East Street, Yulong Community, Xincheng Sub-District Office, Weifang Hi-tech Zone, Shandong Province, China