210pb properties harry nelson 10/9/05
DESCRIPTION
Implantation 214Po 210Pb + α 146 keV ↨ 222Radon 218Polonium+α 214Pb(Lead)+α Τ1/2= 3.8 days 186 seconds 27 minutes 214Pb(Lead) 214Bismuth+β− 214Po+β− Τ1/2= 27 minutes 20 minutes 164 μs 214Po 210Pb + α ↨ 146 keV 8-30 μm 210Pb SRIM: dmax= 50±11 nm Aluminum 35±12 Germanium 58±12 Silicon 13± 7 Tungsten material dmaxTRANSCRIPT
210Pb Properties
Harry Nelson10/9/05
Basic ideas were pursued by Rick G. and Jip starting in 2002: seehttp://cdms.brown.edu/cdms_restricted/backgrounds/montecarlo/GEANT4/demos/Radioactive_BG/and files in that directory prefixed 210Pb_***.
This talk contains some of the plots from the literature on the 210Pb decay complex.See also http://hep.ucsb.edu/people/hnn/backgroundmeeting/pb210.pdf
Implantation222Radon 218Polonium+α 214Pb(Lead)+α
Τ1/2= 3.8 days 186 seconds 27 minutes 214Pb(Lead) 214Bismuth+β− 214Po+β−
Τ1/2= 27 minutes 20 minutes 164 μs 214Po 210Pb + α
↨146 keV
material
210Pb
dmax
dmax= 50±11 nm Aluminum35±12 Germanium58±12 Silicon13± 7 Tungsten
8-30 μm
SRIM:
Endpoint 63.6 keV B.R. 16±3%2 measurements, 1956-7 Quality not great
210Pb β− decay 210Pb22 yr
210Bi*
210Bi
Endpoint 16.96 keV B.R. 84±3% Measurement OK
210Pb β− decay spectra
Jaffe & Cohen, Phys. Rev 89, 454 (1952)
Huster, Phys. Rev 92, 1076 (1953)Pb(CH3)4 vapor in proportional chamberFluorescent X-rays escapeβ−
β−
+ Internal Conversions
High Energy β− branch hard to see…
210Pb High Energy β− decay Stanner & Ross, Proc. Phys. Soc. Lond. A 69, 836 (1956)Emulsion, tagged by Bismuth beta decay
These bins analyzed to estimate High Energy β− branch
L2L1
210Bi* decay: mostly Internal Conversion 210Bi*<3 ns
210Bi
46.539 keV4.25±0.04%
ToIL3
e-
33.12 keV0.50±0.02%
e-
30.83 keV6.0±0.2%
e-
30.15 keV57±2%
Per 210Pb decay
Campbell, J. Phys. A 36, 3219 (2003) Literature Review
24.6±0.8% emitFlourescent x-rays
M
e-
42.6 keV16±5%
N
e-
45.7 keV4.3±1.4%
NOP…
e-
46 keV0.9±0.3%
Mostly Augerelectron emission
Nucl. Data Tables A4, 1 (1968)Nucl. Data Tables A6, 235 (1969)Nucl. Data Tables A9, 119 (1971)Atom. Data. Nucl. Data Tables A81, 1, (2002).
Internal Conversion e- Spectrum (1)
Wu, Boehm, Nagel, Phys. Rev. 91, 319 (1953)
Only measurement I’veFound of M,N,O conversions
Internal Conversion e- Spectrum (2)
Gelletly & Geiger, Nucl. Phys.A123, 369 (1969)
A discrepancy`Missing’ Branching ratio:
From Internal Conversion Coefficients: BR()=5.24±0.18% (note, for *relative* IC rates, data and theory agree well)
Measurement (1990): BR()=4.25±0.04%
Perhaps /electron relative normalization is difficult.
Flourescent 210Bi x-raysCampbell, J. Phys. A 36, 3219 (2003)SiLi Detector
L3L3L3
NNNN
Table of Isotopes
Balance of energy: soft Auger electrons from M and N shell relaxation.
Subsequent Decays210Bismuth 210Polonium+β− 206Pb(Lead)+α
Τ1/2= 5.0 days 138 days Stable 1.16 MeV endpoint 5.3 MeV
210Bismuth beta decay has distorted spectrum,giving more low energy betas relative to higher energy betas than a simple Fermi spectrum. (line at left should be *straight*).
Plassman & Langer, Phys. Rev. 96, 1593 (1954)