Transcript Decay of 177 Lu - Filip G. Kondev
Example of Evaluation: Decay of
177
Lu (6.647 d)
Filip G. Kondev
[email protected]
2 nd Workshop for DDEP Evaluators, Bucharest, Romania May 12-15,2008
Outline
Introduction
nuclear structure properties of 177 Lu
the relevance to applications
Nuclear Data Properties
lifetime
beta and gamma-ray emission probabilities
Atomic Data
Guidelines for Evaluators 2
Nuclear Structure Properties of
177
Lu
deformed rare-earth nucleus with 71 protons and 106 neutrons Q(7/2+) = 3.39(2) eb
m
(7/2+) = 2.239(11)
m
N
Q
( 3
K
2
I
I
( 1 )( 2
I I
1 3 ) )
Q
0 0 .
271 m
g K
g
2
R I
0 .
68 ; (
g K g K
( 7 / 2
g R K
)
I
1 2 [ 404 ]) 0 .
65
Q(23/2-) = 5.2(5) eb
m
(23/2-) =2 .337(13)
m
N Q(
)=500.6(7) keV
G.Audi et al, Nucl. Phys. A729 (2003) 337
3
Why of interest to applications
177 Lu (6.647 d) is a therapeutic radionuclide
used to cure the so-called “metastatic bone disease” – when breast or prostate cancer spreads from their primary sites to the bone – the cure is to use high-energy
particles to the bone
177m Lu (160.44 d) can be used as
g
ray energy & efficiency standards (high multiplicity) & has a potential for energy related applications (e.g. energy storage device)
gamma-ray tracking , where the efficiency depends on
g
ray multiplicity 4
Nuclear Data
Q(
)
G. Audi et al, Nucl. Phys. A729 (2003) 337
http://www.nndc.bnl.gov/qcalc/
Lifetime
need to be evaluated
Emission energies & probabilities (
and
g)
need to know the decay scheme - adopted Ex, J
p
, mult (ENSDF)
a
T – use BRICC (see talk by T. Kibedi)
evaluate E
g
, P
g
,
d
, P
calculate E
,
max , log ft 5
Production of
177
Lu
(n, g )=3.02 (5) b
no contaminants
small production CS
(
n
, g ) 2090 ( 70 )
b
large production CS
but be aware of potential complications 6
Lifetime measurements
A
(
t
)
dN
(
t
) /
dt
N
(
t
)
A
0
e
ln( 2 )
t
/
T
1 / 2
Tag on specific signature radiations (
a, ,
ce or
g)
in a “singles” mode Clock Detector Source
usually follow several T 1/2
statistical uncertainties are usually small
systematic uncertainties (dead time, geometry, etc.) dominate, but often these are not reported 7
Half-life of
177
Lu
not a trivial task – depends on the main production mode – all measurements used 176 Lu(n,
g
) 177 Lu production
T 1/2 , d 6.75 (5) # 6.74 (4) # 6.71 (1) # 6.7479 (7) # 6.645 (30) 6.65 (1) Reference 1958Be41 1960Sc19 1972Em01 1990Ab02 1982La25 2001Zi01 6.646 (5) 6.647 (4) 2001Sc23 Adopted Comments T 1/2 ( 177m Lu)=159.5 d (7) was used in the fitting procedure Corrections for T 1/2 ( 177m Lu) have been applied, but the value has not been reported T 1/2 ( 177m Lu)=160.4 d was used in the fitting procedure
8
Half-life of
177
Lu - cont
E x
6 .
3
MeV
(
n
, g ) 2090
b
J
p 13 / 2 , 15 / 2 (
n
, g ) 2 .
8
b
A
(
t
)
A
0 ( 177
Lu
)
e
T
1 / ln 2 2 ( 1 7 7
Lu
)
t A
0 ( 177
Lu
)
A
0 ( 177
m Lu
)
m
( 177
Lu
) ( 177
m Lu
)
A
0 ( 177
m Lu
)
e
T
1 / ln 2 2 ( 1 7 7
m Lu
)
t
0 .
0012
9
T 1/2 = 6.7479 (7) d 208.4
10
A
(
t
)
A
01
e
t
/ 1
A
02
e
t
/ 2
A
(
t
)
A
0
e
t
/
A
01
A
02
m
( 177 ( 177
m Lu
)
Lu
)
const
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Half-life of
177
Lu
T 1/2 , d 6.75 (5) # 6.74 (4) # 6.71 (1) # 6.7479 (7) # 6.645 (30) 6.65 (1) Reference 1958Be41 1960Sc19 1972Em01 1990Ab02 1982La25 2001Zi01 6.646 (5) 6.647 (4) 2001Sc23 Adopted Comments T 1/2 ( 177m Lu)=159.5 d (7) was used in the fitting procedure Corrections for T 1/2 ( 177m Lu) have been applied, but the value has not been reported T 1/2 ( 177m Lu)=160.4 d was used in the fitting procedure
12
What we want to know accurately: T 1/2 , E g , I g , mult – d & a T E g – determines Ex and E I g , mult., d & a T – determine P (g)
E1(+M2) E2 M1(+E2)
P
i
[
I tot
(
out
)
I tot
(
in
)]
I tot
(
out
/
in
)
i I
g
i
( 1 a
T i
) a
T
(
M
1
E
2 ) a
T
(
M
1 ) 1 d d 2 2 a
T
(
E
2 )
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Gamma-ray energies – example
Reference
1989Ma56 1981Hn03 1967Ha09 1965Ma18 1964Al04 1961We11 1955Ma12
Adopted g 1,0
112.9498 (4) 112.95 (2) 112.95 (2) 112.952 (2) 112.97 (2) 112.97 (2) 112.965 (20)
112.9498 (4)
Lweight 14
Gamma-ray intensities – example
Reference
2001Sc23
g 1,0
59.6 (6) 1987Me17 59.6 (11) 1974Ag01 1964Al04 1961We11 1955Ma12
Adopted
60 (5) 58 (4) 62 (2) 45.5 #
59.7 (5)
Lweight 15
Gamma-ray mixing ratios – example
Reference d(g 1,0 )
1974Kr12 1974Ag01 1970Hr01 1961We11 1972Ho54 1972Ho39 1977Ke12 1992De53
Adopted
-4.7 (2) -3.99 (25) -3.7 (3) -4.0 (2) -4.75 (7) -4.5 (3) -4.8 (2) -4.85 (5)
-4.4(4)
16
P
=9.1 % (2)
E g 113 137 Mult M1+E2 M1+E2 208 E1+M2 I g 6.20 ( 7) 0.0470 (7) 10.38 (7) d -4.4 (4) -3.0 (7) 0.074 (13) a T 2.272
1.158 0.068
a
T
(
M
1
E
2 ) a
T
(
M
1 ) 1 d d 2 2 a
T
(
E
2 )
I tot (137)+I tot (208)=11.19 (7) I tot (113)=20.29 (7)
I
g
tot i
I
g
i
( 1 a
T i
)
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log ft values
ENSDF analysis program LOGFT – both Windows & Linux distribution
http://www.nndc.bnl.gov/nndcscr/ensdf_pgm/analysis/logft/
LOGFT Web interface at NNDC
http://www.nndc.bnl.gov/logft/ 18
Q(
) 13/2-,409.4085
7/2+
13/2 ;
D
I=3;
p
i
p
f =-1 3 rd forbidden
log
f
log
T
1 / exp 2
a
log
P
i a
log
ft
19
from systematics
log
f
1 .
5 log
T
1 / exp 2 5 .
8
from LOGFT from expt.
P
i
( 13 / 2 ) 10 15
19
Q eff
allBR i
1
Q i BR i
;
Q calc
all
g
j
1
E
g
j P
g
j
all
k
1
E
k P
k
all
a
l
1
E
a
l P
a
l
etc
.
Consistenc y
Q eff
Q eff Q calc
100 %
Using RADLST
Decay Mode n CE + Auger g Q calc Q eff Q i , keV 450.8 (20) 13.2 (3) 33.41 (18) 497.4 (25) 498.3 (8)
Consistency = 0.18 % 20
Atomic Data
g
-ray
π E i J i
K L X-ray M Energetics of CE-decay (i=K, L, M,….) E i = E f + E ce,i + E BE,i + T r
π E f J f
emission of X-rays
emission of Auger electrons 21
Where Data Come From?
The X-ray energies: J.A. Bearden, Rev. Mod. Phys. 39 (1967) 78 (also TOI)
Fluorescence yields:
w
K : 1% (Z>35) to 10% (Z=5) -W. Bambynek et al. Rev. Mod. Phys. 44 (1972) 716
w
L : < 4% (Z>29) - E. Schonfeld and H. Janssen, PTB-Report RA-37 (1995)
w
M – J.H. Hubbell et al., J. Phys. Chem. Ref. Data 23 (1994) 339 (fit to expt. data)
Relative K
/K
a
and K
a1
/K
a2
emission rates (<1% assumed):
from E. Schonfeld and H. Janssen, PTB-Report RA-37 (1995) and J.H. Scofield, Phys. Rev. A9 (1974) 1041, respectively
The K- and L-Shell Auger electron energies:
F.P. Larkins, ADNDT 20 (1977) 313
Emission probabilities of K-shell Auger electrons: deduced from X-ray ratios- E. Schonfeld and H. Janssen, PTB-Report RA-37 (1995) 22
Guideline for evaluators
Start with the examination of the known decay scheme
use ENSDF for J
p
, mult., etc. as a first approximation – but check for latest references using the NSR database and be aware of potential differences – create your own ENSDF file – you can use some useful ENSDF programs (ALPHAD, BRICC, GABS, GTOL, LOGFT, & RADLST)
Use Q values from G. Audi et al. mass evaluation (2003Au03)
Evaluate T 1/2 , I
g
, mult.,
a
T &
d
following DDEP rules
use LWEIGHT for statistical analysis of data
Deduce level energies using evaluated transition energies, e.g. E
g
+/-
D
E
g
, etc. (using GTOL for example)
Do the intensity balances of the decay scheme and deduce P
, P
a
, P
g
, etc. for each level (transitions) 23
Guideline for evaluators-cont.
Calculated log ft and/or HF
a
ALPHAD) values (using LOGFT and
Estimate possible week branches (or missing ones) using systematics of log ft and/or HF
a
values – get P
and/or P
a
Check the decay scheme for consistency (using RADLST)
Qeff
allBF i
1
Q i BF i
;
Qcalc
all
g
j
1
E
g
j P
g
j
all
k
1
E
k P
k
all
a
l
1
E
a
l P
a
l
etc
.
Consistenc y
Qeff
Qcalc Qeff
100 %
Get the atomic data using the EMISSION program
need to provide E
g
+/-
D
E
g
, P
g
+/-
D
P
g
and
a
K ,
a
L ,
a
M ,
a
N etc (and their uncertainties)
compare with experimental data, if any, for consistency
Get E
max and E
av.
using LOGFT program 24
Some personal notes …
Be critical to the experimental data you are dealing with!
as all nuclei are different, so are the experiments
A good evaluation is not just simply averaging numbers!
sometime the most accurate value quoted in the literature is not the best one!
Enjoy what you have been doing!
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