Elemental x-ray imaging using Zernike phase contrast
Shao Qi-Gang1, Chen Jian1, Wali Faiz1, Bao Yuan1, Wang Zhi-Li2, Zhu Pei-Ping3, †, 
, Tian Yang-Chao1, ‡, , Gao Kun1, ¶,
, Tian Yang-Chao1, ‡, , Gao Kun1, ¶, Subtraction images: (a) phase contrast, and (b)–(f) absorption contrasts. The sample exposures correspond to PND: 4 × 1010, 4 × 1010, 8 × 1010, 1.2 × 1011, 1.6 × 1011, 2 × 1011 photons/μm2, respectively. The SNRs of the images are 12.6, 7.3, 9.9, 11.9, 13.8, and 15.4, respectively.
