FIGURE 3.11
and
classical
SR spectrum in
quantum regimes.
synchrotron radiation 55
which is explored in detail in further chapters). This corresponds to K « 1 and is called the undulator regime.
As we see, the undulator parameter K ∼ γ λ u /R defines different regimes of synchrotron radiation: K » 1 is the wiggler
regime, K « 1 is the undulator regime.
FIGURE 3.10
Wiggler and undulator radiation.
Fig. 3.10 shows the differences between radiation from a
single bend and from a sequence of bends in wiggler and undulator regimes, respectively. We will consider this topic in
more detail in the Chapters dedicated to light sources and to
FELs, which are respectively 7 and 8.
3.3.6 SR quantum regime
Let’s define the parameter “Upsilon”as Υ = nω c /E. The meaning of this parameter depends on the regimes of SR.
When the parameter Υ « 1, its physical meaning is the
ratio of the characteristic photon energy to the energy of a
single electron in the beam.
However, when Υ ∼ 1 and higher, the classical regime of
synchrotron radiation is not applicable, and the quantum SR
formulae of Sokolov–Ternov should be used. Such a situation
may happen in particular in collision or highly relativistic
focused beam, e.g., in linear colliders.
In a quantum regime, the shape of the SR spectrum
changes, as there should not be a photon emitted that has
energy larger than the energy of the initial particle.
The qualitative dependence of the SR spectrum in classical and quantum regimes is shown in Fig. 3.11.
Though the quantum
to occur in
SR
radiation
is unlikely
from bends, it can happen in SR during beam collisions, as
beams focused to tiny spots can produce enormous fields that
cause the oncoming particles to radiate in a quantum regime.
and
classical
SR spectrum in
quantum regimes.
synchrotron radiation 55
which is explored in detail in further chapters). This corresponds to K « 1 and is called the undulator regime.
As we see, the undulator parameter K ∼ γ λ u /R defines different regimes of synchrotron radiation: K » 1 is the wiggler
regime, K « 1 is the undulator regime.
FIGURE 3.10
Wiggler and undulator radiation.
Fig. 3.10 shows the differences between radiation from a
single bend and from a sequence of bends in wiggler and undulator regimes, respectively. We will consider this topic in
more detail in the Chapters dedicated to light sources and to
FELs, which are respectively 7 and 8.
3.3.6 SR quantum regime
Let’s define the parameter “Upsilon”as Υ = nω c /E. The meaning of this parameter depends on the regimes of SR.
When the parameter Υ « 1, its physical meaning is the
ratio of the characteristic photon energy to the energy of a
single electron in the beam.
However, when Υ ∼ 1 and higher, the classical regime of
synchrotron radiation is not applicable, and the quantum SR
formulae of Sokolov–Ternov should be used. Such a situation
may happen in particular in collision or highly relativistic
focused beam, e.g., in linear colliders.
In a quantum regime, the shape of the SR spectrum
changes, as there should not be a photon emitted that has
energy larger than the energy of the initial particle.
The qualitative dependence of the SR spectrum in classical and quantum regimes is shown in Fig. 3.11.
Though the quantum
to occur in
SR
radiation
is unlikely
from bends, it can happen in SR during beam collisions, as
beams focused to tiny spots can produce enormous fields that
cause the oncoming particles to radiate in a quantum regime.