Energy Loss Routines

The energy loss routines in CREME are based on the following papers:

• S.P. Ahlen, "Z⁷₁ Stopping Power Formulae for Fast Heavy Ions", Physical Review A17, 1236 (1978).
• S.P. Ahlen, "Calculation of the Relativistic Bloch Correction to Stopping Power", Physical Review A25, 1856 (1982).
• J.D. Jackson and R.L. McCarthy, "Z³ Corrections to Energy Loss and Range", Physical Review B6, 4131 (1972).
• R.M. Sternheimer and R.F. Peirels, "General Expression for the Density Effect for the Ionization Loss of Charged Particles", Physical Review B3, 3681 (1971).

Preliminary comparisons between the CREME energy-loss routines and the Stopping and Range of Ions in Matter (Version 96.02; SRIM96) program by Ziegler and Biersach shows only small discrepancies which are irrelevant for SEU effects:

• The most significant discrepancy appears near the peak of the Fe stopping power curve, at ~ 1 MeV/nuc: the SRIM96 stopping power is larger here than CREME's by about 15%. The origin of this discrepancy is not yet understood; but it is too small to have any practical impact in SEU calculations.
• A systematic discrepancy between the CREME and SRIM96 codes appears at ion energies below ~0.1 MeV/nuc. At these very low energies (where ion ranges are less than 1 micron), SRIM96 shows stopping powers which monotonically decrease with decreasing energy. CREME, on the other hand, shows stopping powers which increase with decreasing energy below ~0.1 MeV/nuc. This low-energy "turn-up" in the CREME stopping power curves is due to atomic collisions after the projectile nucleus has captured electrons from the medium. It may be that such collisions are neglected in the SRIM code. In any case, this discrepancy has no significant impact on SEU calculations.