STUDIES OF ENERGY RECOVERY LINACS AT ... - CASA

FIG. 2.3: Additional hardware installed to energy recover the beam in CEBAF. The
phase delay chicane is installed in an empty cryomodule slot denoted as 2L23 and the
beam dump is installed in empty cryomodule slot 2L22. An overhead view of the region
is given in the upper drawing and a ground level view is on the bottom.
required to energy recover the beam in CEBAF, a phase delay chicane and a beam
dump and beamline outfitted with appropriate diagnostics. These components were
installed in regions of the south linac denoted as 2L22 and 2L23 and are shown in
Fig. 2.3. The new hardware did not interfere with CEBAF’s primary function of
providing beam to the nuclear physics community. The energy recovery experiment
was noninvasive in the sense that with the dipole string of the phase delay chicane
deactivated, it remains transparent to standard CEBAF operations.
The CEBAF-ER experiment operated with a one-pass up, one-pass down scheme.
The electron beam was injected into the north linac at 56 MeV where it was acceler-
ated to 556 MeV. The beam traversed arc 1 and then began acceleration through the
south linac where it reached a maximum energy of 1056 MeV. Following the south
linac, the beam passed through the newly installed phase delay chicane and through
arc 2. The chicane generated a path length differential of 1/2-RF wavelength so that
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