X23A2 Beamline Evaluation: Detector Linearity

The linearity of the detectors is tested in this test. The horizontal hutch slits were set to 5 mm for these tests.

The first test, shown on the left below, measured the ratio of I_t to I_r as a vertical knife edge is moved through the sample. The same setup was used for this test as for the noise tests. The knife traveled from a position completely out of the beam on the left of the plot to blocking about 95% of the beam on the right.

The second test, shown on the right below, scans the hutch slits through the beam to test the linearity across the ion chambers. The slits were set to a horizontal opening of 1mm for this test.

The slit scan test was very successful, with the rms variation down at the 1 part in 10,000 level. The knife scan test was considerably worse, with the linearity suffering as the signal became small.