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

11

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 )

13

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

)

17

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!

25