Example of Evaluation: Decay of 177 Lu (6.647 d) Filip G. Kondev 2 nd Workshop for DDEP Evaluators, Bucharest, Romania May 12-15,2008

2 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

3 Q(23/2-) = 5.2(5) eb  (23/2-) =2.337(13)  N Nuclear Structure Properties of 177 Lu deformed rare-earth nucleus with 71 protons and 106 neutrons Q(  )=500.6(7) keV G.Audi et al, Nucl. Phys. A729 (2003) 337 Q(7/2+) = 3.39(2) eb  (7/2+) = 2.239(11)  N

4 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 ( d) can be used as  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  ray multiplicity

5 Nuclear Data  Q(  ) G. Audi et al, Nucl. Phys. A729 (2003)  Lifetime need to be evaluated  Emission energies & probabilities (  and  need to know the decay scheme - adopted Ex, J , mult (ENSDF)  T – use BRICC (see talk by T. Kibedi) evaluate E , P , , P  calculate E  max, log ft

6 Production of 177 Lu no contaminants small production CS b large production CS but be aware of potential complications  (n,  )=3.02 (5) b

7 Lifetime measurements Tag on specific signature radiations (  ce or  in a “singles” mode  usually follow several T 1/2  statistical uncertainties are usually small  systematic uncertainties (dead time, geometry, etc.) dominate, but often these are not reported Detector Source Clock

8 Half-life of 177 Lu T 1/2, dReferenceComments 6.75 (5) #1958Be (4) #1960Sc (1) #1972Em (7) #1990Ab (30)1982La25T 1/2 ( 177m Lu)=159.5 d (7) was used in the fitting procedure 6.65 (1)2001Zi01Corrections for T 1/2 ( 177m Lu) have been applied, but the value has not been reported (5)2001Sc23T 1/2 ( 177m Lu)=160.4 d was used in the fitting procedure (4)Adopted not a trivial task – depends on the main production mode – all measurements used 176 Lu(n,  ) 177 Lu production

9 Half-life of 177 Lu - cont b b

10 T 1/2 = (7) d 208.4

11

12 Half-life of 177 Lu T 1/2, dReferenceComments 6.75 (5) #1958Be (4) #1960Sc (1) #1972Em (7) #1990Ab (30)1982La25T 1/2 ( 177m Lu)=159.5 d (7) was used in the fitting procedure 6.65 (1)2001Zi01Corrections for T 1/2 ( 177m Lu) have been applied, but the value has not been reported (5)2001Sc23T 1/2 ( 177m Lu)=160.4 d was used in the fitting procedure (4)Adopted

13  E  – determines Ex and E    I , mult.,  &  T – determine P  E1(+M2) M1(+E2) E2  What we want to know accurately: T 1/2, E , I , mult –  T

14 Gamma-ray energies – example Reference  1,0 1989Ma (4) 1981Hn (2) 1967Ha (2) 1965Ma (2) 1964Al (2) 1961We (2) 1955Ma (20) Adopted (4) Lweight

15 Reference  1,0 2001Sc (6) 1987Me (11) 1974Ag0160 (5) 1964Al0458 (4) 1961We1162 (2) 1955Ma # Adopted59.7 (5) Gamma-ray intensities – example Lweight

16 Reference    1974Kr (2) 1974Ag (25) 1970Hr (3) 1961We (2) 1972Ho (7) 1972Ho (3) 1977Ke (2) 1992De (5) Adopted-4.4(4) Gamma-ray mixing ratios – example

17 I tot (113)=20.29 (7) I tot (137)+I tot (208)=11.19 (7) EE MultII TT 113M1+E26.20 ( 7)-4.4 (4) M1+E (7)-3.0 (7) E1+M (7)0.074 (13)0.068 P  =9.1 % (2)

18  ENSDF analysis program LOGFT – both Windows & Linux distribution log ft values  LOGFT Web interface at NNDC

19 13/2-, Q(  ) 7/2+  13/2-;  I=3;  i  f =-1 3 rd forbidden from systematics from LOGFT from expt.

20 Decay ModeQ i, keV  (20) CE + Auger13.2 (3)  (18) Q calc (25) Q eff (8) Consistency = 0.18 % Using RADLST

21 Atomic Data  -ray K L M E i J i π E f J f π  emission of X-rays  emission of Auger electrons Energetics of CE-decay (i=K, L, M,….) E i = E f + E ce,i + E BE,i + T r X-ray

22  The X-ray energies: J.A. Bearden, Rev. Mod. Phys. 39 (1967) 78 (also TOI)  Fluorescence yields:  K : 1% (Z>35) to 10% (Z=5) -W. Bambynek et al. Rev. Mod. Phys. 44 (1972) 716  L : 29) - E. Schonfeld and H. Janssen, PTB-Report RA-37 (1995)  M – J.H. Hubbell et al., J. Phys. Chem. Ref. Data 23 (1994) 339 (fit to expt. data)  Relative K  /K  and K  /K  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) Where Data Come From?

23 Guideline for evaluators  Start with the examination of the known decay scheme use ENSDF for J , 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 , mult.,  T &  following DDEP rules use LWEIGHT for statistical analysis of data  Deduce level energies using evaluated transition energies, e.g. E  +/-  E , etc. (using GTOL for example)  Do the intensity balances of the decay scheme and deduce P , P , P , etc. for each level (transitions)

24 Guideline for evaluators-cont.  Calculated log ft and/or HF  values (using LOGFT and ALPHAD)  Estimate possible week branches (or missing ones) using systematics of log ft and/or HF  values – get P  and/or P   Check the decay scheme for consistency (using RADLST)  Get the atomic data using the EMISSION program need to provide E  +/-  E , P  +/-  P  and  K,  L,  M,  N etc (and their uncertainties) compare with experimental data, if any, for consistency  Get E  max and E  av. using LOGFT program

25 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!