ABSTRACT
These properties allow experiments which are complementary to experiments at laboratory X-ray sources.
2.2 Production of synchrotron radiation [1-3] Synchrotron radiation is generated by bunches of electrons (or positrons) which circulate at relativistic energies close to the speed of light. In the simplest case, the electrons follow a circular orbit, which is defined by dipole magnets. As shown in Figure 2.2, the emitted radiation covers a range from the infrared to γ -rays. It is concentrated in a cone with opening angle *, which is centered on the tangent to the orbit (Figure 2.3). * can be expressed at the critical wavelength – λc (equation 2) – approximately by the so-called γ -ratio:
* ≈ γ−1 = (1957E)−1 (1) where E is the energy of the electrons (GeV). The critical wavelength, λc (nm), is defined at the wavelength where half of the total power is emitted according to:
λc = 0.559(R/E3) (2)
— #2
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where R (m) is the radius of curvature of the electrons in the bending magnet. The variation of λc with energy implies that several GeV of electron energy are required in order to obtain a sufficiently powerful beam in the hard X-ray regime.
