R. Medenwaldt et al., COHERENT RADIATION FROM 70 GEV AND 150 GEV ELECTRONS AND POSITRONS TRAVERSING DIAMOND AND SI CRYSTALS NEAR AXIAL AND PLANAR DIRECTIONS, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 103(2), 1995, pp. 139-146
Channeling radiation and energy loss for 150 GeV electrons and positro
ns incident on a 0.5 mm thick [100] diamond and a 0.6 mm thick [110] S
i crystal have been measured - near axial and planar directions. It is
found that yields from well channeled electrons are enhanced by a fac
tor of two, and those for positrons are reduced by a factor of five, a
s compared to yields outside the channeling region, The experimental c
ritical angle for channeling agrees very well with the Lindhard angle
psi 1. For incidence along planes and close to axial directions, the o
verall picture of the radiation spectra for electrons and positrons is
the same for the high-energy photons, where a strongly enhanced peak
is found, as was first discovered in an earlier electron experiment, I
n diamond, the standard coherent bremsstrahlung has been measured clos
e to the {110} planes but for 10 mrad and 50 mrad from the axis, These
experimental results agree well with calculations using the Born appr
oximation.