def evaluate_power(ripple, gamma):
    """helper function to score ripple/gamma power ratio"""
    tmp = ripple/gamma
    scoreRG = 0
    if tmp > 20.:
        scoreRG = 3
    elif 10. < tmp <= 20.:
        scoreRG = 2
    elif 2. <= tmp <= 10.:
        scoreRG = 1
    return scoreRG