Generation of positrons via pair-creation from Compton scattered gamma-rays

An important role of positron (e(+)) polarization in future linear collider s is discussed in terms of effective polarization, which is closely related to the clear observation of interesting reaction processes in e(-)e(+) col lisions. In order to verify our proposed method, in which highly polarized e(+) can be generated through Compton scattering of laser light off a relat ivistic electron (e(-)) beam, we performed an experiment to prove the princ iple and observed e(+) productions for the first time. It was found that th e production rates of ei are not only consistent with those of e(-) and gam ma-ray but also in good agreement with numerical estimations. (C) 1999 Publ ished by Elsevier Science B.V. All rights reserved.