Analysis of the 206Pb(n,) cross section

•Angular distribution effects in the capture yield

)(cos5.01)( 2 PW )(cos5.01)( 2 PW

%42/3

3/2-

M1 E2

+10% -10%

Analysis of the 206Pb(n,) cross section

•Angular distribution effects in the capture yield

)(cos5.01)( 2 PW )(cos5.01)( 2 PW

%42/3

3/2-

M1 E2

+10% -10%

206Pb(n,) Maxwellian Average CS (MACS)

%42/3

(MACS) = 3-4%

• Resonances 1/2 show NO angular distribution effect

• Resonances 5/2 do show, but their contribution to the total CS is negligible.

206Pb(n,) Maxwellian Average CS (MACS)

%42/3

(MACS) = 3-4%

-20%

-9%

• Bao et al. based on ORNL Exp, Mizumoto 1979, who used two C6F6 at 90o

• Imortant to quantify the effect of the angular distribution

206Pb(n,) Maxwellian Average CS (MACS)

• Mughabghab 2006 based on A. Borella's private com. from Geel Exp.

• Geel setup also 125o similar to n_TOF setup

All n_TOF Pb/Bi Maxwellian Average CS (MACS)

• R. Gallino

•S. Bisterzo

Some preliminary astrophysical implications

238UT1/2=4.5x109y

N(206Pb) = 0.6009(8%) (Lodders 2003)

Ns(206Pb) = 0.4206(9%) (This Work + AGB-Model Calc.)

Nr(206Pb) = Nr(209Bi)x8/12 = 0.075(9%) (209Bi MACS + AGB + Approx.)

Nrad(206Pb) = N(206Pb) - Ns(206Pb) - Nr(206Pb) = 0.105(15%)

N(238U) = 0.0187(8%) (Lodders 2003)

Some preliminary astrophysical implications

N(206Pb) = 0.6009(8%) (Lodders 2003)

Ns(206Pb) = 0.4206(9%) (This Work + AGB-Model Calc.)

Nr(206Pb) = Nr(209Bi)x8/12 = 0.075(9%) (209Bi MACS + AGB + Approx.)

Nrad(206Pb) = N(206Pb) - Ns(206Pb) - Nr(206Pb) = 0.105(15%)

N(238U) = 0.0187(8%) (Lodders 2003)

= 6.7(1.0) Gy

T= + 4.6 + 0.5 = 12(1) Gy

time duration of r-nucleosynthesis

decay rate of 238U

r supernova rate (-1.5 to -2x10-10 y)

1)exp()exp(

)exp(1

r

r

r

r

Fowler's exponential model

The paper

The problem of the angular distribution with C6D6

125o

The problem of the angular distribution with C6D6

125o

The problem of the angular distribution with C6D6

125o