Ni-08-22-13

Nickel foils were placed in front of and behind the Au+Sand, the blank crucible, and the gold foil. Nickel foils were also place in front of and behind the crucible with the Barium Oxide.

lines are observed near, 238, 511, 578, 604, 903, 1264, 1362 keV

Naturally occurring Isotopes of Nickel are

Ni-58 ( 68.077% ) Ni-60 ( 26.223% ) Ni-61 ( 1.140% ) Ni-62 ( 3.634% ) Ni-64 ( 0.926% )

Neutron knockout

Ni-58 ->Ni-57 has the following lines in order of decreasing intensity: 511, 1377, 127 , 1919 half life = 35.6 hours

Ni-60 -> Ni-59 : no high intensity lines above 100 keV, half life 7e4 years

Proton knockout

Ni-58-> Co-57 : 122,136, half life 271.74 days

N-P knockout

Ni-58->Co-56 :847, 1238, 511, 2599, 1771, 1038, half life = 77 days

Extracting Photon flux using Nickel Foil

The two reactions below can be used to extrapolate the photon flux

[math]{58 \atop 28 }Ni_{76}(\gamma,n){57 \atop 28 }Ni_{75}[/math]

Ni-57 has a 35.6 hour half life with high intensity lines at 511 (87%) and 1377.63 (81.7%)

[math]{58 \atop 28 }Ni_{76}(\gamma,2n){56 \atop 28 }Ni_{74}[/math]

Ni-56 has a day half life with intensity lines at 158 (87%) and 811 (81.7%)

Since the two neutron knockout reaction requires a higher photon energy one may be able to estimate the bremmsstrahlung distribution by requiring that the ratio of the integral for photon energies allowing single neutron knockout to the integral for two neutron knockout match the observed counting rate that has included cross -section

Energy needed to liberate a neutron from the Nucleus

Neutron Separation Energy=[math]S_n = B({A \atop Z} X_{N})-B({{A-1} \atop Z} X_{N-1})[/math]

[math]B({58 \atop28} Ni_{76}) = 506,453.842 keV[/math] [math]B({57 \atop28} Ni_{75}) = 494,234.980 keV[/math] [math]B({56 \atop28} Ni_{74}) = 483,987.827 keV[/math]

Neutron Separation Energy for [math]{58 \atop 28 }Ni_{76}(\gamma,n){57 \atop 28 }Ni_{75}[/math]

=[math]S_n = B({58 \atop 28} Ni_{76})-B({{57} \atop 28} X_{75})= 506,453.842 - 506,453.842 = 12218.862 keV = 12.218862 MeV [/math]

2 Neutron Separation Energy for [math]{58 \atop 28 }Ni_{76}(\gamma,2n){56 \atop 28 }Ni_{74}[/math]

=[math]S_n = B({58 \atop 28} Ni_{76})-B({{56} \atop 28} X_{74})= 506,453.842 - 483,987.827 = 22,466.015 keV = 22.466015 MeV [/math]

Unfortunately the electron beam energy may have been 22 MeV thereby forbidding two neutron knockout.

PAA_8-22-13#Nickel_normalization_foils

A_W_thesis