2.4.3 Injection Components
Having accomplished the miracle of accelerating a particle beam to almost the
velocity of light, how does one feed this beam into the circular orbit of a synchrotron
or storage ring? A series of dc magnets bends the beam coming from the transport
line into a trajectory almost parallel to the ring orbit. Then, a special, short pulse
septum magnet is used to bend the beam the final degree or two, as close as possible
to the stored beam orbit. As the electron beam circulates around the ring, a kicker
magnet is used to give its orbit an outward deflection so that it can merge with the
injected pulses. Then, the kicker magnet and septum magnet are rapidly turned off so
orbits of subsequent bunches are not affected (Fig. 2.13).
2.4.4 Vacuum, Thermal, and Radiation Protection
Technology
A massive infrastructure of more conventional technology is required to support the
operation of a storage ring. All of the accelerator technology discussed so far
requires ultra-high vacuum in the chambers containing the beams. Chemistry lab
vacuum lines have pressures ranging from (10
À2 to 10
À4 torr) for routine Schlenk
lines or better (10
À4 to 10
À7 torr) for high vacuum lines with diffusion pumps or
turbo pumps. Storage rings typically operate at least several orders of magnitude
better still, on the order of 10
À10 torr [28].
To achieve and maintain this vacuum, the chambers are initially connected with
turbomolecular pumps backed by dry mechanical pumps during the bakeout. During
operations, the chamber vacuum is maintained with a combination of sputter ion
pumps, non-evaporable getter (NEG) pumps, and titanium sublimation pumps
(TSP).
Managing the thermal load from synchrotron radiation requires careful engineering, because without sufficient cooling the beam could melt most metals. The
synchrotron radiation that does not go down the beamline is often absorbed by a
massive water-cooled copper block known as a “crotch,” with ion and titanium
sublimation pumps placed close by.
Fig. 2.13 Left: A SPring-8 diagram showing the injection system. Right: cross section of a storage
ring vacuum vessel
2.4 Other Components
27
Having accomplished the miracle of accelerating a particle beam to almost the
velocity of light, how does one feed this beam into the circular orbit of a synchrotron
or storage ring? A series of dc magnets bends the beam coming from the transport
line into a trajectory almost parallel to the ring orbit. Then, a special, short pulse
septum magnet is used to bend the beam the final degree or two, as close as possible
to the stored beam orbit. As the electron beam circulates around the ring, a kicker
magnet is used to give its orbit an outward deflection so that it can merge with the
injected pulses. Then, the kicker magnet and septum magnet are rapidly turned off so
orbits of subsequent bunches are not affected (Fig. 2.13).
2.4.4 Vacuum, Thermal, and Radiation Protection
Technology
A massive infrastructure of more conventional technology is required to support the
operation of a storage ring. All of the accelerator technology discussed so far
requires ultra-high vacuum in the chambers containing the beams. Chemistry lab
vacuum lines have pressures ranging from (10
À2 to 10
À4 torr) for routine Schlenk
lines or better (10
À4 to 10
À7 torr) for high vacuum lines with diffusion pumps or
turbo pumps. Storage rings typically operate at least several orders of magnitude
better still, on the order of 10
À10 torr [28].
To achieve and maintain this vacuum, the chambers are initially connected with
turbomolecular pumps backed by dry mechanical pumps during the bakeout. During
operations, the chamber vacuum is maintained with a combination of sputter ion
pumps, non-evaporable getter (NEG) pumps, and titanium sublimation pumps
(TSP).
Managing the thermal load from synchrotron radiation requires careful engineering, because without sufficient cooling the beam could melt most metals. The
synchrotron radiation that does not go down the beamline is often absorbed by a
massive water-cooled copper block known as a “crotch,” with ion and titanium
sublimation pumps placed close by.
Fig. 2.13 Left: A SPring-8 diagram showing the injection system. Right: cross section of a storage
ring vacuum vessel
2.4 Other Components
27