Overview of endep

This note gives a description of the operation of the endep code, and it is an updated version of Chapter III of the Omega manual [3]. The purpose of endep is to determine the average energies of secondary particles, residual nuclei, and gammas, when the given data includes angular distributions or energy distributions of secondary particles. One difference between the current endep and that discussed in Chapter III of [3] is that the treatment of reactions induced by incident gammas is no longer done by endep but is done separately as described by the note [2]. I also wish to point out that much of the theory presented here is also given in Perkins's PD-note [5]. I have made some repetition here for the sake of completeness.

At the end of this section I explain the usage of the endep_diff code, to compare two sets of energy-deposition files for a target.

The reader should also be aware of the related code nxgam, which has the purpose of modelling gamma energy spectra when only average gamma energies are available. The theoretical basis for nxgam is given in [4], and the instructions for use of that code are contained in the note [6].

The endep code handles the following basic reactions:

1.

The modelling of discrete two-body reactions is discussed in Section 2. For these reactions the user must supply a file in ENDL format of angular distributions for the secondary particle ( $\tt I\_number$ = 1 data).

2.

Section 3 discusses the treatment of continuum two-body reactions. For these reactions the user must supply a file in ENDL format of energy distributions for the secondary particle ( $\tt I\_number$ = 4 data).

3.

Either of the above types of reactions may produce an unstable residual nucleus. The continuum decay of such a nucleus is described in Section 4. For each particle emitted the user must supply a file in ENDL format of energy distributions ( $\tt I\_number$ = 4 data).

In addition, as explained in Section 5, endep has special coding for the treatment of gamma production, fission, and the breakup of deuterium, carbon, and beryllium.