Beam distribution parameters before IBS:
    emit_a      :   3.800000000000000E-009
    emit_b      :   1.790000000000000E-011
    sigmaE_E    :   8.126045314880993E-004
    sigma_z     :   9.214969169335188E-003
 
 Beam distribution parameters after IBS:
    emit_a      :   1.119898859262764E-008
    emit_b      :   2.027889776673552E-011
    sigmaE_E    :   8.738823344027307E-004
    sigma_z     :   9.909862001878045E-003