The Reduction of Instrumental Helicity-Dependent Intensity Asymmetries in an Optical Train
Abstract
False asymmetries that mimic true parity violation signals are a serious systematic problem in the search for electron circular dichroism (ECD) [1, 2] as well as general parity violation experiments [3]. The source of many of these problems can be traced to the optical train of the polarized electron sources used in such experiments. Until recently, efforts to reduce these false asymmetries in our lab have been limited to passive techniques, such as careful alignment and temperature stabilization of the system. We report here work with an acoustic optical modulator (AOM) to actively control these false asymmetries. A significant reduction in helicity-correlated intensity asymmetries has been achieved. In addition a piezo-electric controlled mirror has been used to reduce a spatial asymmetry with computer-controlled feedback. [1] S. Mayer and J. Kessler, Phys. Rev Lett. 74, 4803 (1995). [2] K.W. Trantham, M.E. Johnson, and T.J.Gay J. Phys. B 28 L543 (1995). [3] T. Averett, C.E. Jones, R.D. McKeown, and M. Pitt, Nucl. Instrum. Methods A 438, 246 (1999).
- Publication:
-
APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004APS..DMP.J1079Z