Undergraduate Research at Jefferson Lab

Improvement of Hall D Vacuum for Klong Experiment

Student: Lauren Bueter

School: Old Dominion University

Mentored By: Timothy Whitlatch

Within the next few years, experimental Hall D of Jefferson Laboratory will be introducing the Klong experiment, that will use a beamline under vacuum. The vacuum beamline between Hall D and Tagger Hall is 90 feet long with a 10-inch diameter and is stainless steel. It is covered in concrete and is underground, with only the ends being accessible. The existing vacuum pump is a Hi Cube 300 Pro, DN 100 ISO-K, Duo 11 M. Currently the beamline is at a pressure of 5e^-6 Torr, but the experiment requires the existing vacuum to be improved by 10 times (to 5e^-7 Torr). Simple hand calculations will be made to begin understanding the problem. From there, variables will be adjusted to better understand what is needed to reach the desired vacuum level. Once it is known what needs to be changed to get the desired pressure, a practical situation could be designed and calculated. Following this, the variables will be put into a simple vacuum calculation program to verify that the hand calculations were made correctly. The calculations and program have shown that not only will a better pump be needed, but will also need one pump on each side, attached directly to the beampipe. Before calculations were made, it was originally thought that only a singular, improved, pump would be needed to reach the required pressure. Following calculations, however, it was found that such a simple change would not be enough to reach such a pressure. With the improvement of the vacuum pump and the addition of a pump, the pressure of the system will reach the desired pressure. This means that when the Klong experiment is running, the beam going through the pipe will run into less molecules, create less radiation, and lead to better results for the experiment.

[Watch the presentation on YouTube]