Hydrogen, oxygen and carbon losses during ¹⁵N bombardment of PMMA layers

We have studied the behaviour of thin PMMA layers during high energy ¹⁵N irradiation. Employing the ¹H(¹⁵N, αγ)¹²C and ¹²C(d, p)¹³C reactions after ¹⁵N preirradiation we determined the total energy loss of ¹⁵N ions as well as the hydrogen, carbon, and oxygen contributions in dependence upon the ¹⁵N fluence φ. Due to release effects the energy losses of the ¹⁵N ions within the PMMA films are reduced to about 0.3 of the initial values at φ = 5 × 10¹⁴ cm^-2. At fluences φ > 2 × 10¹⁴ cm^-2 the (oxygen plus carbon) contribution becomes constant and the change of the energy loss can be explained by hydrogen release alone.