Abstract. Electron screening enhances nuclear reaction cross sections at low energies. We studied the nuclear reaction 1 H( 19 F,αγ) 16 O in inverse kinematics in different solid hydrogen targets. Measured resonance strengths differed by up to a factor of 10 in different targets. We also studied the 2 H(p,γ) 3 He fusion reaction and observed electrons emitted as reaction products instead of γ rays. In this case electron screening greatly enhances internal conversion probability.