Abstract
This paper details a laser beam delivery and pointing stabilization system designed for the Laser-Assisted Charge Exchange (LACE) experiment at the Spallation Neutron Source (SNS) accelerator. The UV (355 nm) laser beam of 140 mJ pulses at 10 Hz must be transported over 65 m through a retrofitted laser transport line in a high-radiation area of the accelerator, causing the alignment of the beam to jitter and drift significantly on timescales of 0.1–1 s and >1 min, respectively, due to thermal effects and other disturbances. The laser pointing stabilization system is based on a novel technique which uses active feedback between CMOS cameras and a piezoelectric steering mirror controlled by feedback software to make corrections to the horizontal angle and vertical position of the laser beam at 10 Hz. Low frequency drift is easily controlled, and the long-term stability is limited by the amplitude of high frequency components of the spectrum near the Nyquist limit (5 Hz). With feedback turned on, the root-mean-square (RMS) deviations of the horizontal angle and vertical position over 20 min fell from 314 to 157 μrad and 309 to 167μm, respectively, which is below the pulse-to-pulse jitter at 10 Hz of 189 μrad RMS and 180μm RMS.
| Original language | English |
|---|---|
| Article number | 168548 |
| Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
| Volume | 1055 |
| DOIs | |
| State | Published - Oct 2023 |
Funding
We would like to thank Sarah Cousineau and all the members of the LACE Team at the SNS for their guidance and input in bringing this project to fruition. We would also like to thank Sydney Murray III and Anthony Webster for their technical assistance. This research used resources of the Spallation Neutron Source, which is a DOE Office of Science User Facility. This work has also been partially supported by the U.S. DOE Grant No. DE-FG02-13ER41967. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). The U.S. government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan [29]. We would like to thank Sarah Cousineau and all the members of the LACE Team at the SNS for their guidance and input in bringing this project to fruition. We would also like to thank Sydney Murray III and Anthony Webster for their technical assistance. This research used resources of the Spallation Neutron Source, which is a DOE Office of Science User Facility. This work has also been partially supported by the U.S. DOE Grant No. DE-FG02-13ER41967 . This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy (DOE) . The U.S. government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan [29] .
Keywords
- Charge exchange injection
- Hydrogen ion
- Laser stabilization
- Optical systems
- UV laser