Dusa, S. Covrig | Engineering Papers

DOE OSTI2024

Strong interaction physics at the luminosity frontier with 22 GeV electrons at Jefferson Lab

Here, the purpose of this document is to outline the developing scientific case for pursuing an energy upgrade to 22 GeV of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Facility (TJNAF, or JLab). This document was developed with input from a series of workshops held in the period between March 2022 and April 2023 that were organized by the JLab user community and staff with guidance from JLab management (see Sec. 10). The scientific case for the 22 GeV energy upgrade leverages existing or already planned Hall equipment and world-wide uniqueness of CEBAF high-luminosity operations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

The Q weak high performance LH 2 target

A high-power liquid hydrogen target was built for the Jefferson Lab Q weak experiment, which measured the tiny parity-violating asymmetry in $\vec{e}$ p scattering at an incident energy of 1.16 GeV, and a Q 2 = 0.025 GeV 2 . To achieve the luminosity of 1.7 x 10 39 cm -2 s -1 , a 34.5 cm- long target was used with a beam current of 180 μA. The ionization energy-loss deposited by the beam in the target was 2.1 kW. The target temperature was controlled to within ±0.02 K and the target noise (density fluctuations) near the experiment's beam helicity- reversal rate of 960 Hz was only 53 ppm. The 58 liquid liter target achieved a head of 11.4 m (7.6 kPa) and a mass flow of 1.2 ± 0.3 kg/s (corresponding to a volume flow of 17.4 ± 3.8 l/s) at the nominal 29 Hz rotation frequency of the recirculating centrifugal pump. We describe aspects of the design, operation, and performance of this target, the highest power LH2 target ever used in an electron scattering experiment to date.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗