the atomic masses - nucleide.org masses… · iii ‐the atomic mass evaluation 3 iv ... vi...

THE ATOMIC MASSES Georges AUDI

[email protected]

I ‐ INTRODUCTION TO THE NUCLEUS – 1NUCLEAR BINDING ENERGY

II ‐ EXPERIMENTAL METHODS FOR MEASURING MASSES 2III ‐ THE ATOMIC MASS EVALUATION 3IV ‐ THE ATOMIC MASS ADJUSTMENT PROGRAM V ‐ ESTIMATES OF UNKNOWN MASSES 4VI ‐ NUBASE VII ‐ The AMDC

csnsm G. Audi

ISOMERS ANDNUBASE� gs – isomer identification

if �-emission�NSDD

if no � �decay energy to other nuclide�� AME

� NUBASE ‘horizontal’ evaluationhalf-livesspin and paritiesdecay modes��which state is the ground-state��which states are involved in a

massrelation� Other needs for NUBASE

radioactive parameters for calculationsreactors

waste management

nuclear astrophysics

prepare nuclear physics experiment

��

� �� %�� '

��),�- � (�� <�� ,

� ��

� ��=�� =�� :��

� ��!�� =��, �B� /�=��3

� ��%�� %�� '

��- �� ( �� , �"��#�

��- � ( �� , ��

��- � ( �� , ��

� ��

� �� "3��#�

. "��

� % ��(�*� �� >�� ?

@ "��

) '��!4��C�� 0��

�) -��& �� 0��

�) 0��&� '��& 0��

"��

Precision for 14N

year

Mea

sure

men

t pre

cisi

on

1940 1960 1980 2000

10

-11

10

-10

10

-9

10

-8

10

-7

10

-6

10

-5

10

-4

14N

One order of magnitude every 10 years• 1935: 400 keV• 1995: 0.9 eV• 2003: 0.5 eV

Csnsm Georges Audi

50 years of mass evaluations

The more recent history of atomic masses can be found in:

Georges Audi

“The history of nuclidic masses and of their evaluation”

International Journal of Mass Spectrometry 251 (2006) 85–94

An early (perhaps the first) attempt for a mass evaluation is

M.S. Livingston, H.A. Bethe, “Nuclear Physics, C. Nuclear dynamics, experimental”,

Rev. Mod. Phys. 9 (1937) 245, XVIII. Nuclear masses; p. 366

The authors combined data from mass spectrometry and nuclear reaction and

decay data up to 40Ar.

In the early 1950’s it was found that the many relations (direct and indirect)

overdetermined the mass value of many nuclides.

Aaldert H. Wapstra established a procedure using a least-squares method to

solve the problem of overdetermination.

The first table of atomic masses using this method is dated 1955.

History of Wapstra’s type AME A.H. Wapstra, Physica 21 (1955) 367 + 385; J.R. Huizenga, Physica 21 (1955) 410

F. Everling, L.A. König, J.H.E. Mattauch, A.H. Wapstra, Nucl. Phys. 18 (1960) 529

L.A. König, J.H.E. Mattauch, A.H. Wapstra, Nucl. Phys. 31 (1962) 18

J.H.E. Mattauch, W. Thiele, A.H. Wapstra, Nucl. Phys. A67 (1965) 1 + 32 + 73

A.H. Wapstra & K. Bos, At. Data Nucl. Data Tables 19 (1977) 175

A.H. Wapstra, G. Audi & R. Hoekstra, Nucl. Phys. A432 (1985) 185

G. Audi & A.H. Wapstra, Nucl. Phys. A 565 (1993) 66

C. Borcea, G. Audi, A.H. Wapstra & P. Favaron, Nucl. Phys. A 565 (1993) 158

G. Audi, A.H. Wapstra & M. Dedieu, Nucl. Phys. A 565 (1993) 193

G. Audi & A.H. Wapstra, Nucl. Phys. A 595 (1995) 409 ; an update

A.H. Wapstra, G. Audi & C. Thibault, Nucl. Phys. A 729 (2003) 129

G. Audi, A.H. Wapstra & C. Thibault, Nucl. Phys. A 729 (2003) 337

Evaluation of Nuclear Data

• Theoretical evaluation (= theoretical predictions)

predict values for large sets of nuclei

make effective calculations for : r-process - reactors - . . .

uncertainties : just starting security <=> feasibility

• Evaluation of experimental data

basic blocks : results from experiments

if available : prefered to theoretical predictions

allows also to test theoretical “evaluations”

Csnsm Georges Audi

��

� ��%� ��

�!��& �� ' �� #�'

7�8�� -��

�� @��

7�8� �� -��

��

� �� (��&

�!��& �� ) �*�

� ��(�& ��

.� =�>� "?�.� �� %�

�� "��+

�� ( �$�9�9�� :�A�

�� ( �$�9�9��$ � ��$� :�A

"��

��

� ��"�� :��

&)�� *� �� 1 � �� "

5 10 15 200

0

X m

b a

σ

� 7��-� �.��:��

, �� , ��

� 7�-�� .��:�� + ;��

,� �!��

��$� �� , ��

$��

��

� �� #�� !��

�� . �� 1 � �� "

MaxX Xmin

��,�� <��

$��

��

� �� $� ��

(-� � �� 5��-� �� " ��

�� ;<( 5��-�

�� =�� . ��

4�� . ��

MaxX Xmin

�� - ��> �� #

��,�� <��

�� -�� 0�� #�� >

�� 4��$ �

��: �$�$��: ��=�$��

$��

��

� ��

(�� 5��-� �� " �� $ ��

�� ? �+ $&��>

�� -�� 0�� >

�� 4��

$��$: ��

� �� >

�� 4 ��: �$�$��: �$��: $

$ ��

$ : �� $��

$��

��

�

�

�

��

CSNSM-OrsayMISTRAL Collaboration

��

��

��

��

��

��

��

��

��

��

��

!��

��"#��

��

� ��

��

� ��! �� $� ��

&��

1�� ) ��

1�� 1��A 1�� 0 )�� 0 C�-��

:�-��. �� . ��

$��'�� "

>�� /�.��

D��

'�6�� - )��

��

$��

��

� �� %� ��

� &�� ! � ' �$��

� ��) ��

� ��

� ��

� ��

'��A �� # ��

�0��--��-

�� # ��

0

N Z

N ZN Z

N Z

n n

odd odd

even odd

odd even

even even

∆

∆

∆

∆

∆

n p

n n

p p

p p

� �� $� ��(

�$�� )��

� ��( ��! �� *�� &��!

$��

Regularity of the Mass Surface II• New Physics

• Coherent deviations in (N, Z)⇒ new physical property (e.g. 23N15 N = 108− 115 Cs63−112 )

• Outliers

• One single ‘Irregularity’⇒ question correctness of datum

re-measure same and/or measure neighborsstrongly deviating 1-experiment (chaotic surf.):

⇒ replace by estimated ‘recommended’ value

• Conflict among Data⇒ which one agrees with estimate?

• Unknown Masses⇒ Estimates : Interpolate - Extrapolate

Csnsm Georges Audi

Regularity of the Mass Surface III

• Extrapolations (short extrapolations)

from regularity of the surface of massesfor medium and heavy nuclides

consider several graphs

knowledge of n-stable or n-unstablefor light n-rich nuclides

similar for p-rich ← but Coulomb !!

mirror and IMMEfor light p-rich nuclides

Csnsm Georges Audi

Neutron Number N

Mex

p-M

Duf

lo-Z

96

sph.

+Z

*1.0

(M

eV)

Fig. 6. Mass Exp-Mass Duflo-Z 96 sph. N= 70 to 118

70 75 80 85 90 95 100 105 110 115

70 75 80 85 90 95 100 105 110 115

60

62

64

66

68

70

72

74

76

60

62

64

66

68

70

72

74

76

149Nd142Nd 152Pm

135Pm 155Sm

133Sm 167Eu

133Eu

169Gd

134Gd

171Tb

136Tb

173Dy138Dy

175Ho140Ho

177Er143Er

179Tm145Tm

181Yb

148Yb

184Lu

150Lu

188Hf

153Hf

190Ta

155Ta

190W

157W

187Re159Re

Recent observationsof the mass surface

• Magic numbers vanishing (quenching)

when going far from stability

earlier : N = 20, N = 28

now also (since Ame2003) : N = 50, N = 82

• Rising of the wings

Qβ’s often underestimated

r-process paths less far from stability

expected influence on reactors and on waste calculations

Csnsm Georges Audi

Neutron Number N

Mex

p-M

Duf

lo-Z

96

sph.

+Z

*1.0

(M

eV)


10 15 20 25 30 35 40 45

10 15 20 25 30 35 40 45

12

14

16

18

20

22

24

26

28

12

14

16

18

20

22

24

26

28

40Mg

21Mg

42Al

22Al

44Si

23Si

46P

24P

49S

26S

51Cl 28Cl 53Ar

30Ar55K

32K57Ca

34Ca

60Sc

36Sc

63Ti

38Ti

65V

40V

67Cr

42Cr

69Mn

44Mn

72Fe

45Fe

65Co 47Co

Neutron Number N

Mex

p-M

Duf

lo-Z

96

sph.

+Z

*1.0

(M

eV)


20 25 30 35 40 45 50 55 60 65

20 25 30 35 40 45 50 55 60 65

24

26

28

30

32

34

36

38

40

24

26

28

30

32

34

36

38

40

67Cr 44Cr

69Mn 45Mn

72Fe

45Fe

75Co

47Co

78Ni

48Ni

80Cu

52Cu

83Zn

54Zn

86Ga

56Ga

89Ge

58Ge

92As

60As

94Se

64Se

97Br 67Br

100Kr 69Kr

102Rb 71Rb

104Sr

73Sr

105Y 76Y

80Zr

78Zr

Neutron Number N

Mex

p-M

Duf

lo-Z

96

sph.

+Z

*1.0

(M

eV)


35 40 45 50 55 60 65 70 75 80 85

35 40 45 50 55 60 65 70 75 80 85

36

38

40

42

44

46

48

50

52

36

38

40

42

44

46

48

50

52

100Kr

76Kr

102Rb 71Rb

105Sr

73Sr

108Y 76Y

110Zr

78Zr

113Nb

81Nb

115Mo

83Mo

118Tc

85Tc

120Ru

87Ru

122Rh

89Rh

124Pd

91Pd

130Ag

93Ag

132Cd

95Cd

135In

97In

136Sn 99Sn

137Sb103Sb

TO CONCLUDE

• Deriving a mass value from one or several experiments

sometimes requires expertise

• Mathematical tools (LSM)

+ computer tools+ evaluator’s judgment

are essential ingredients to reach the best possible mass-values———————————————————————————-• unknown masses

• close to last ones : predicted from extension of mass surface• further out : derived from models.

but models diverge!!! (10’s of MeV in region of r-process)

• therefore:

• best possible experimental data• best possible evaluation of masses −→best set of mass values

on which models may 1) adjust their parameters2) improve predictions further away

Csnsm Georges Audi

csnsm G. Audi

NUCLEAR DATA

� Static Nuclear Datamasses�� & ��

excitation energiesdecay modes at rest and intensitiesdecay from excited statesneutron capture cross-sectionsmagnetic moments & radii. . .

� Dynamic Nuclear Datareaction cross-sectionsreaction ratesreaction mechanismsspectroscopic factors. . .

"Static" Nuclear Data

Z = 1Z = 2

Z = 3Z = 4

A =

1A

= 2

A =

3A

= 4

A =

291

A =

292

A =

293

structuresand

decays(Ensdf)

(NSDD network)

masses (Ame)

Ame:created by A.H. Wapstra (Amsterdam) in 1959 since 1981 together with G. Audi (Csnsm − Orsay)

interaction Ame Ensdf=> NUBASE : masses

isomers EmT1/2

Jπdecay modes & intensities

“Horizontal Evaluations”

• Atomic Mass Evaluation AME

Wapstra since 1959 + G.A. since 1981

• NUBASE

Blachot, Bersillon, Wapstra, G.A. since 1993

• Radii, spins and moments

• Isotopic abundances Holden

• E2+ and B(E2) for e-e nuclides

• . . .

Csnsm Georges Audi

The Nubase evaluation of Nuclear and Decay Properties

Ground state

Isomeric states, > 100 ns • Masses

• T1/2

• Jπ

• Decay modes and intensities

AMDC : the Atomic Mass Data Centerhttp://amdc.in2p3.fr/

• Mass Evaluations Ame’83, Ame’93, Ame’95 and Ame2003texts, tables, figures of the publication + extra figs. and bonus

• Nubase Evaluation Nubase’97 and Nubase2003• Preprints on masses :

Experimental– Evaluation – Theory• Other products :

jvNubase – Nucleus PC-program – . . .+ Ensdf-files + . . .

+ BULLETIN e-mail• 1000 addressees• activities related to masses

Evaluation – Experimental – Theory

MEETING POINT andEXCHANGES −→MASSES

Registration by e-mail: amdc.audi @ gmail.com

Csnsm Georges Audi

the atomic masses - nucleide.org masses… · iii ‐the atomic mass evaluation 3 iv ... vi...

Documents