Abstract. We consider the problem of derandomizing random walks in the Euclidean space R k. We show that for k = 2, and in some cases in higher dimensions, such walks can be simulated in Logspace using only poly-logarithmically many truly random bits. As a corollary, we show that the Dirichlet Problem can be deterministically simulated in space O(log n √ log log n), where 1/n is the desired precision of the simulation. 1

The purpose of this master thesis is to simulate suitable nuclear reactions for a commissioning experiment, to be performed with the AGATA γ-ray tracking spectrometer. The main aim of the work is to find a reaction, which gives large Doppler effects of the emitted γ rays, with as small contribution as possible due to the energy and angular spread of the nuclei emitting the γ rays. Inverse kinematics heavy-ion (HI) fusion reactions of the type (HI,γ), (HI, n) on proton and deuteron targets have been studied. Target effects were investigated using the program TRIM in order to determine the impact on the Doppler effects caused by energy and angular straggling in the target material. The cross sections of a large number of reactions of protons and deuterons on nuclei with mass numbers in the range A ≈ 20−100 have been evaluated using the TALYS reaction code. The fusion-evaporation reactions, d () 51 52 ( V, n Cr and d 37Cl,) 38 n Ar were simulated in detail using the Monte Carlo code evapOR. The interactions in AGATA of the γ rays emitted in these