Abstract: A radiation beam modulator (1; 500; 600) that can be employed for modulating a radiation beam (60) in a radiation system. The modulator (1; 500; 600) comprises a bath (590; 690) containing a radiation attenuating fluid (520; 620) and multiple low radiation attenuating bars (570; 670) immersed in the fluid (520; 620) to form an array of multiple columns (525; 625). A height adjuster (530; 630) is arranged for adjusting a respective level of immersion of the bars (570; 670) in the fluid (520; 620) thereby to adjust the heights of the fluid columns (525; 625) such that the columns (525; 625) collectively form a radiation beam modulating profile.

Abstract: The present invention involves a radiation beam modulator (1; 100; 200; 300; 400; 500; 600) that can be employed for modulating a radiation beam (60) in a radiation system. The modulator (1; 100; 200; 300; 400; 500; 600) comprises an array of multiple columns (125; 225; 325; 425; 525; 625) of a radiation modulating fluid or liquid (120; 220; 320; 420) and a height adjuster (130; 230; 330; 430; 530; 630). This height adjuster (130; 230; 330; 430; 530; 630) adjusts the heights of the multiple fluid columns (125; 225; 325; 425; 525; 625) so that the adjusted columns (125; 225; 325; 425; 525; 625) collectively will form a target radiation modulating profile. In a first embodiment, the modulator (100; 200; 300; 400) includes a bundle of capillaries (150; 250; 350; 450) in which the modulating fluid (120; 220; 320; 420) is conveyed to form the columns (125; 225; 325, 425).