Monochromatic high-energy γ rays from positron annihilation in single-crystal silicon
Bochek G.L., Vit'ko V.I., Grishaev I.A., Kovalenko G.D., Kulubaba V.I., Morokhovskii V.L., Shramenko B.I.
It is shown that the channeling of 1-GeV positrons in a silicon single crystal 300 μ thick changes appreciably the emission spectrum of the channeling positrons in comparison with the emission spectrum of the positrons of an amorphous target: the bremsstrahlung intensity (Jbr) decreases by a factor of 4.4 and that of the annihilation radiation (/ап„щ) decreases by a factor 1.6, thus increasing the ratio Annih/ibr by 2.7 times.