Abstract
Utilizing noninvasive 2D scans with laser wires, we tomographically reconstructed the 4D transverse phase space distribution of a 1-GeV hydrogen ion (i.e., H-) beam during operation. The 4D tomography is based on two new advances. First, we extended the formulation of maximum entropy phase space tomography to take 2D projections as input and derived theoretical results relevant to our application. Second, we introduced the method of "perpendicular scans"to obtain cross-plane information from a laser wire emittance scanner. Perpendicular scans are two unconventional 2D measurements performed with perpendicular front and back wires. In contrast, only parallel front and back wires (i.e., "parallel scans") are utilized in ordinary measurements of the horizontal and vertical 2D phase space distributions. When we applied the technique to the laser emittance station in the high-energy beam transport of the Spallation Neutron Source, experimental results showed that perpendicular scans can provide significant new information to the reconstructed 4D phase space distribution.
| Original language | English |
|---|---|
| Article number | 042801 |
| Journal | Physical Review Accelerators and Beams |
| Volume | 25 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2022 |
Funding
We are grateful to Alexander Zhukov from Oak Ridge National Laboratory for suggesting the use of perpendicular scans as a source of cross-plane information. This research used resources of the Spallation Neutron Source, which is a DOE Office of Science User Facility. 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 .