ZhETF, Vol. 127,
No. 1,
p. 5 (January 2005)
(English translation  JETP,
Vol. 100, No. 1,
p. 1,
January 2005
available online at www.springer.com
)
COULOMB CORRECTIONS TO BREMSSTRAHLUNG IN ELECTRIC FIELD OF HEAVY ATOM AT HIGH ENERGIES
Lee R.N., Milstein A.I., Strakhovenko V.M., Schwarz O.Ya.
Received: April 29, 2004
PACS: 12.20.Ds, 95.30.Cq
We consider the differential and partially integrated cross sections for bremsstrahlung from highenergy electrons in the atomic field, with this field taken into account exactly. We use the semiclassical electron Green's function and wave functions in an external electric field. It is shown that the Coulomb corrections to the differential cross section are very susceptible to screening. Nevertheless, the Coulomb corrections to the cross section summed over the finalelectron states are independent of screening in the leading approximation in the small parameter 1/mr_{scr} (r_{scr} is the screening radius and m is the electron mass, ). We also consider bremsstrahlung from a finitesize electron beam on a heavy nucleus. The Coulomb corrections to the differential probability are also very susceptible to the beam shape, while the corrections to the probability integrated over momentum transfer are independent of it, apart from the trivial factor, which is the electronbeam density at zero impact parameter. For the Coulomb corrections to the bremsstrahlung spectrum, the nexttoleading terms with respect to the parameters ( is the electron energy) and 1/mr_{scr} are obtained.

