def calculate_transmission(thickness_cm: np.float, atoms_per_cm3: np.float, sigma_b: np.array):
miu_per_cm = calculate_linear_attenuation_coefficient(atoms_per_cm3=atoms_per_cm3, sigma_b=sigma_b)<EOL>transmission = calculate_trans(thickness_cm=thickness_cm, miu_per_cm=miu_per_cm)<EOL>return miu_per_cm, transmission<EOL>
calculate the transmission signal using the formula

    transmission = exp( - thickness_cm * atoms_per_cm3 * 1e-24 * sigma_b)

    Parameters:
    ===========
    thickness: float (in cm)
    atoms_per_cm3: float (number of atoms per cm3 of element/isotope)
    sigma_b: np.array of sigma retrieved from database

    Returns:
    ========
    transmission array