[en] It is of great importance to provide an experimental demonstration of the coherence of the radiation of electromagnetic waves from a short bunch of electrons performing oscillations in a direction transverse to the main direction of motion. It is known that electrons circulating in a storage ring lose energy to synchrotron radiation. Another method to stimulate radiation is to let an electron bunch travel through a wiggler or an ondulator device. In either case the spectrum usually peaks in correspondence of wavelengths considerably smaller the length of the electron bunch in this situation the power radiated is then linearly proportional to the number N of electrons in the bunch, as it is customarily observed. Nevertheless, it may be possible conceiving a situation where the bunch length is considerably smaller or at least comparable to the wavelength of the peak of the radiation spectrum. If this is the case, it is then speculated that the power radiated is proportional to the square N² of the number of particles in the bunch. This effect, which we can call a coherent effect, if of course very important since it would help to enhance the amount of the power radiated with a lower electron intensity. Unfortunately the coherent effect is difficult to observe since it is not easy to create beam and trajectory parameters which yield a bunch of length smaller than the radiation wavelength. We thus propose here an experiment which has the two goals: to generate an experimental situation where electrons in a bunch of length ell radiate electromagnetic power at a variable wavelength λ, and to observe with measurements the total amount of radiation versus λ and the beam intensity N. This experiment can be executed at the Accelerator Test Facility either at Brookhaven or at Argonne National Laboratory