Calculation of atomic radiations in nuclear decay – BrIccEmis and beyond
T. Kibèdi, B.Q. Lee, A.E. Stuchbery, K.A. Robinson
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Outline
Talk is largely based on Kȧlmȧn Robertson (ANU) Honours project (2010)
Boon Quan Lee (ANU) Honours project (2012)2012Le09 Lee et al., “Atomic Radiations in the Decay of Medical Radioisotopes: A Physics Perspective”Computational and Mathematical Methods in MedicineVolume 2012, Article ID 651475, doi:10.1155/2012/651475
2011 NSDD meeting (IAEA)
Radiative and Non-radiative atomic transitions in nuclear decay
Nuclear and atomic data Existing programs to evaluate atomic radiations New model based on Monte Carlo approach Future directions
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Atomic radiations - Basic concept
1S
2S2P
3S3P
3D
K
L1
L2
L3
M1
M2
M3
M4
M5
Initial vacancy
Vacancies on the inner-shell can be produced by electron impact photo ionization ion-atom collision internal conversion electron capture secondary processes
accompanyingb-decay or electron capture
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Atomic radiations - Basic concept
1S
2S2P
3S3P
3D
K
L1
L2
L3
M1
M2
M3
M4
M5
Initial vacancy
X-ray emission
X-ray
photon
Ka2 X-ray1 secondary
vacancy
22 LKX EEEK
a
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Atomic radiations - Basic concept
K
L1
L2
L3
M1
M2
M3
M4
M5
Initial vacancy1S
2S2P
3S3P
3D
K
L1
L2
L3
M1
M2
M3
M4
M5
Initial vacancy
X-ray emission
Ka2 X-ray1 secondary
vacancy
22 LKX EEEK
a
X-ray
photon
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Atomic radiations - Basic concept
K
L1
L2
L3
M1
M2
M3
M4
M5
Auger-electron
Auger-
electron
23232
LLLKLLK EEEE
K L2 L3 Auger-electron2 new secondary
vacancies
1S
2S2P
3S3P
3D
K
L1
L2
L3
M1
M2
M3
M4
M5
Initial vacancy
X-ray emission
X-ray
photon
Initial vacancy
Ka2 X-ray1 secondary vacancy
22 LKX EEEK
a
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Atomic radiations - Basic concept
K
L1
L2
L3
M1
M2
M3
M4
M5
Coster-Kronig electron
CK- electro
n
2121121
LMLLMLL EEEE
L1 L2 M1 Coster-Kronig transition
2 new secondary vacancies
1S
2S2P
3S3P
3D
K
L1
L2
L3
M1
M2
M3
M4
M5
Initial vacancy
X-ray emission
X-ray
photonInitial
vacancy
22 LKX EEEK
a
Ka2 X-ray1 secondary vacancy
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Atomic relaxation and vacancy transfer
K
L1
L2
L3
M1
M2
M3
M4,5
N1
N2,3
N4,5
O1,2,3
A vacancy cascade in Xe From M.O. Krause, J. Phys. Colloques, 32 (1971)
C4-67
X
AA
AAA
KC
AAAAAAAA Full relaxation of an initial inner
shellvacancy creates vacancy cascade involving X-ray (Radiative) and Auger as well as Coster-Kronig (Non-Radiative) transitions Many possible cascades for a
single initial vacancy Typical relaxation time ~10-15
seconds Many vacancy cascades
following a single ionisation event!Initial
vacancy
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Transition energies and Rates
Auger-electron
X-ray emission
Number of primary vacancies
For a single initial vacancy on the K-shell following nuclear decay
T
KK Pn
aa
1Internal conversion
Electron captureKK PPn
Energy YKX EEEKY
XYXKKXY EEEE
Intensity KKX nIKY
KKKXY anI 1 KK a
for L1 shell )( 312111 LLLLLKXYL ffanI
1312111 LLLLLL ffa
111 LLX nIYL
in an ion
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Medical applications - Auger electrons
Kassis, Int. J. of Radiation Biology, 80 (2004) 789
electrons
Biological effect: Linear energy transfer LET, keV/mm
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Medical applications - Auger electrons
2011 August, INDC International Nuclear Data Committee Technical Meeting on Intermediate-term Nuclear Data Needs for Medical Applications: Cross Sections and Decay DataEdited by A.L. Nichols, et al., NDC(NDS)-0596
(Courtesy of Thomas Tunningley, ANU).
Auger emitters: 67Ga , 71Ge, 77Br, 99mTc, 103Pd, 111In, 123I, 125I, 140Nd, 178Ta, 193Pt, 195mPt, 197Hg
Targeted tumor therapy
Regaud and Lacassagne (1927)“The ideal agent for cancer therapy would consist of heavy elements capable of emitting radiations of molecular dimensions, which could be administered to the organism and selectively fixed in the protoplasm of cells one seeks to destroy.”
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Existing calculationsPhysical approach
RADAR DDEP Eckerman & Endo(2007)
Howell(1992)
Stepanek(2000)
Pomplun(2012)
Nuclear decay data
ENSDF DDEP ENSDF ENSDF ENSDF ICRP38
Conversion coefficients
HsIcc RpIcc/BrIcc RpIcc,1978 Band
RpIcc 2000 Stepanek HsIcc,1971 Dragoun,
1976 Band
Electron Capture Ratios
1971 Gove & Martin
1995 Schönfeld 1977 Bambynek 1971 Gove & Martin,
1970Martin
1971 Gove & Martin,
1970Martin
1971 Gove & Martin
Atomic transition rates
1972 Bambynek,RADLST
1974 Scofield,1995 Schönfeld
& Janßen,2006 Be et al.,
EMISSION
1991 Perkins,EDISTR04
1979 Chen,1972/1975 McGuire,
1983 Kassis, 1974 Scofield, 1974
Manson & Kenedy
1991 Perkins 1979 Chen,1972/1975
McGuire, 1970 Storm & Israel, 1979 Krause
Atomic transition energies
1970 Bearden & Burr, Neutral
atom
1977 Larkins,Semi-empirical
1991 Perkins, Neutral atom
Z/Z+1 (Auger),Neutral atom (X-
ray)
Dirack-Fock calculation
1991 Desclaux, Dirack-Fock calculation
Vacancy propagation
Deterministic Deterministic Deterministic(+++)
Monte Carlowith charge
neutralization
Monte Carlo Monte Carlo
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Existing calculationsAuger electron yield per nuclear
decayRADAR DDEP Eckerman &
Endo(2007)
Howell(1992)
Stepanek(2000)
Pomplun(2012)
99mTc (6.007 h) 0.122 0.13 4.363 4.0 2.5
111In (2.805 d) 1.136 1.16 7.215 14.7 6.05
123I (13.22 h) 1.064 1.08 13.71 14.9 6.4
125I (59.4 d) 1.77 1.78 23.0 24.9 15.3 12.2
201Tl (3.04 d) 0.773 0.614 20.9 36.9
Vacancy propagation
Deterministic Deterministic Deterministic(+++)
Monte Carlowith charge
neutralization
Monte Carlo Monte Carlo
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Existing programs
Common problems / limitations In some cases neutral atom binding energies are used for
atoms with vacancies; i.e. for ions Single initial vacancy is considered. Secondary vacancies are
ignored Atomic radiations only from primary vacancies on the K and
L shell Limited information on sub-shell rates Auger electrons below ~1 keV are often omitted
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
BrIccEmis – Monte Carlo approach for vacancy creation and
propagation Initial state: neutral isolated atom Nuclear structure data from ENSDF Electron capture (EC) rates: Schönfeld (1998Sc28) Internal conversion (IC) coefficients: BrIcc (2008Ki07) Auger and X-ray transition rates: EADL (1991 Perkins)
Calculated for single vacancies! Auger and X-ray transition energies: RAINE (2002Ba85)
Calculated for actual electronic configuration! Vacancy creation and relaxation from EC and IC are
treated independently Ab initio treatment of the vacancy propagation:
Transition energies and rates evaluated on the spot Propagation terminated once the vacancy reached the
valence shell
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
BrIccEmis
Reads the ENSDF file, evaluates absolute decay intensities of EC, GAMMA, CE and PAIR transitions
Simulates a number (100k-10M) radioactive decays followed by atomic relaxation
Electron configurations and binding energies stored in memory (and saved on disk). New configurations only calculated if needed. (55Fe: 15 k, 201Tl: 1300k)
Emitted atomic radiations together with shells involved stored like histories in large files (several Gb)
Separate files for X-rays and Auger electrons Smaller programs to sort/project energy spectra, produce
detailed reports
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
111In EC – vacancy propagation
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
99mTc atomic radiations
2.1726 keV below L-shell BE
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
99mTc atomic radiations – X-rays
DDEP BrIccEmisKa1 18.3672
4.21E-218.4214.05E-2
Ka2 18.2512.22E-2
18.3022.13E-2
Kb 20.6771.30E-2
20.7291.18E-2
L [2.134:3.002]4.82E-3
2.4664.72E-3
M 0.2637.83E-4
N 0.0478.73E-1
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
99mTc atomic radiations – Auger electrons
DDEP BrIccEmis
KLL [14.86:15.58]1.49E-2
15.371.48E-2
KLX [17.43:18.33]2.79E-3
17.855.58E-3
KXY [19.93:21.00]2.8E-4
20.275.07E-4
K-total2.15E-2
16.152.08E-2
CK LLM 2.08E-20.054
CK LLX 0.1449.48E-3
LMM 2.0169.02E-2
LMX 2.3281.41E-2
LXY 2.6546.07E-4
L-total [1.6:2.9]1.089E-1
1.7651.24E-1
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
99mTc atomic radiations – Auger electrons
DDEP BrIccEmis
CK MMX 0.1047.10E-1
MXY 0.1701.10E+0
Super CK NNN 0.0145.36E-1
CK NNX 0.0128.45E-1
Total yield Auger electron per nuclear decay 0.13 3.37
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
BrIccEmis: spectrum from 10 M simulated decay events
99mTc Auger electrons
No experimental spectrum to compare with
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
111In – experiment vs calculation
E.A. Yakushev, et al., Applied Radiation and Isotopes 62 (2005) 451
• ESCA; FWHM = 4 eV• Calculations normalized to the strongest experimental line
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
111In – experiment vs calculation
A. Kovalik, et al., J. of Electron Spect. and Rel. Phen. 105 (1999) 219• ESCA; FWHM = 7 eV• Calculated energies are higher• KL2L3(1D2) energy (eV):
• Multiplet splitting could not be reproduced in JJ coupling scheme
• Similar discrepancies have been seen in other elements (Z=47, Kawakami, Phys. Lett A121 (1987) 414)
19319.2(14) Experiment Kovalik (1999)
19308.1 Semi-empirical Larkins (1979La19)
19381 RAINE (2002Ba85)
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
K-shell binding energies for superheavy elements (2012Ki04)
2002Ga47 & 2008Th05: Breit magnetic electron interaction and the quantum electrodynamical (QED) corrections.
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Breit and other QED contributions (2002Ga47)
Z=49 (In)~60 eV
Alternative solution:Semi empirical corrections, like Larkins (1977La19) or Carlson (1977Ca31) used
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
131mXe IT – charge state at the end of atomic relaxation
Only a handful of measurements exist for ionization by nuclear decay
131mXe: F. Pleasonton, A.H. Snell, Proc. Royal Soc. (London) 241 (1957) 141
37Ar: A.H. Snell, F. Pleasonton, Phys. Rev. 100 (1955) 1396
Good tool to asses the completeness of the vacancy propagation
BrIccEmis: mean value is lower by ~0.7-1.0 charge
Tibor Kibèdi, Dep. of Nuclear Physics, Australian National University DDEP Workshop, Paris, 8-10 October 2012
Summary RelaxData/BrIccRelax
BrIccEmis: calculation intensive approach (hours to days) RelaxData (under development):
Nuclear decay event (EC or CE) produces a SINGLE INITIAL vacancy
Considering a single atomic vacancy the relaxation process independent what produced the vacancy
Compile a database of atomic radiation spectra for produced by a single initial vacancy on an atomic shell Carry out calculations of all elements and shells
Example: 55Fe EC, 7 shells for Z=25 and 26, calculated in couple of hours (1 M each shell)
Replace EADL fixed rates and binding energies from RAINE with GRASP2k/RATIP calculations
BrIccRelax (under development): Evaluate primary vacancy distribution and construct atomic spectra from the data base (20 seconds for 55Fe EC)