PART1 Survey of General properties of Beta decay PART2 Beta decay and nuclear astrophysics PART3 Beta decay in n-rich nuclei

PART1

Survey of General properties of Beta decay

PART2

Beta decay and nuclear astrophysics

PART3

Beta decay in n-rich nuclei

-  in-flight fragmentation facilities -  ISOL facilities

-  TAS experiments

PART1

Survey of General properties of Beta decay

3

Beta  Decay:    universal  term  for  all  weak-­‐‑interaction         transitions  between  two  neighboring  isobars

Takes  place  is  3  different  forms

β-, β+ & EC  (capture  of  an  atomic  electron)

β - :  n  à  p  +  e-­‐‑  +  ν ∼             β+:  p  à  n  +  e+  +  ν      

a  nucleon  inside  the  nucleus  is  transformed  into  another

EC:  p  +  e-­‐‑  à  n  +  ν      

Beta decay: survey of general properties

4

•  β

decay

–  β

decay –  β

decay

–  Electron capture (EC)

•  β

decay is the most common type of radioactive decay –  All nuclides not lying in the valley of stability can β

decay

pe

n →

ν

ne

p →

ν

n

pe

→ ν

Beta decay: survey of general properties (1)

5

Beta decay: survey of general properties (2)

Because beta decay is a three body decay, the electron energy spectrum is a continuum

β^- decay is a weak interaction

“semileptonic” decay

The quark level Feynman diagram for β^- decay is shown on left

6

•  The Q value in beta decay is

effectively shared between the electron and antineutrino

–  The electron endpoint energy is Q

( ) ( )

( )

(

)

( ) ( )

( ) ( )

max max

1 , 1

,

2 1

, ,

:

!

!

since 1

, ,

is decay for

value

c m Z

A M Z

A M Q

note

T T

Q

keV T

T T

T T

T Q

Z A M Z

A M Q

Q

e e

Z A e M

Z e A M

−

−

−

=

=

=

<

+

≈ +

+

=

+

−

=

+

−

+ +

−

−

+ +

−

β β ν

ν β ν

β

β Note these are

atomic masses

Beta decay: survey of general properties (3)

7

Ε

I_iπ_i

I_fπ_f

β

β

S

L I

I

=

+ + _π

_π

= (− 1 )

)

~( )

(β ν ν

β

β

l l

L =

+ S

= s

+ s

= {

allowed forbidden

when  the  angular  momentum   conservation  requires  that  

L

=n

>0  and/or  π

π

=-­‐‑1

1 ,

≡ 0

−

=

Δ I I

I

when    L

=n=0  and  π

π

=+1

 L

 =  n  defines  the  degree  of  forbiddenness  (n)

Classification of β decay transition

8

0+

Ε

1+

Fermi

↓↑

β

= 0

0 S

β

= L

≡ 0

−

=

Δ I I

I

) 1 ( π _i π _f = +

Gamow-­‐‑Teller

0+

Ε

0+

= 0

L

S

=1 ↑↑ or ↓↓

≡ 1

−

=

Δ I I

I

2+

Ε

2+

Δ I = I

− I

≡ 0 I

≠ 0

mixed  Fermi  &  Gamow-­‐‑Teller

Classification of allowed decay

9

Type  of  transition Order  of  

forbiddenness ΔI π_iπ _f

Allowed 0,+1 +1

Forbidden  unique

1 2 3 4 .

 2

 3

 4

 5 .

-­‐‑1 +1 -­‐‑1 +1 .

Forbidden

1 2 3 4 .

0,  1

 2

 3

 4 .

-­‐‑1 +1 -­‐‑1 +1 .

Classification of β decay transitions

10

The  fifth  power  beta  decay  rule:

the  speed  of  a  β  transition  increases  approximately  in  proportion  to  the   fifth  power  of  the  total  transition  energy  (if  other  things  are  being  equal,   of  course)

q   depends  on  spin  and  parity  changes  between  the  initial  and  final  state q   additional  hindrance  due  to  nuclear  structure  effects  :

 isospin,  “l-­‐‑forbidden”,  “K-­‐‑forbidden”,  etc.  

( ^{( ) ( 1 )} ) ^{2 ] 5}

1 [

c Z

M Z

M − ±

τ ∝

Ε

I_f I_i

Useful empirical rules

11

P

T T t

β β

exp 2 / 1 2

/

1

=

≡

∫ ⁻

=

n

g p W W W F Z W C dW

T

2 3 0

2 2

/ 1

) ,

( )

2 ( 2

ln

π

partial  half-­‐‑life  of  a  given

decay  branch  (i)

g  –  week  interaction  coupling  constant p

 –  momentum  of  the  β  particle

W

 –  total  energy  of  the  β  particle

W

 –  maximum  energy  of  the  β  particle

F(Z,W

)  –  Fermi  function  –  distortion  of  the  β  particle  wave  function  by  the   nuclear  charge

C

 –  shape  factor Z  –  atomic  number

β decay lifetime

•  Treat beta decay as a transition that depends upon the strength of coupling between the initial and final states

•  Decay constant is given by Fermi's Golden Rule

–  matrix element which couples the initial and final states –  a phase space factor which describes the volume of

phase space available for the outgoing leptons –  Small system perturbation

•  Contained within M

•  E is Q value

•  Rate proportional to the strength of the coupling between the initial and final states factored by the density of final states available to the system

dv V

M E

M

⁼ ∫

= π ρ ψ ψ

λ

²

^{( );}



Fermi Golden Rule

•  Based on probability of electron energy emission coupled with spectrum and the Coulomb correction f

t

is called the

comparative half life of a transition

•  Assumes matrix element is independent of energy (true for allowed transitions)

•  Yields ft (or f

t

), comparative half-life

–  may be thought of as the half life corrected for differences in Z and W

•  f

can be determine when Fermi function is 1 (low Z)

•  Rapid estimation connecting ft and energy

o

if

f

M t K

2 2

/ 1

2 ln = λ =

∫ ^{− −}

=

=

Wo

o o

o

dW W

W W

W W Z F f

h g

c m K

1

2 2

/ 1 2

7 2

4 5 4

) (

) 1 (

) ,

(

/ 64 π

Comparative Half Lives

•  Z is daughter and E

is maximum energy in MeV (Q value)

•  Log ft = log f + log t

–  t_1/2 in seconds

) 1 log(

5 . 3 6 . 5 log

0 . 2 log

log 3 )

1 (

009 .

0 007

. 0 79 . 0 log

0 . 4 log

log ) 1 (

005 .

0 02

. 0 78 . 0 log

0 . 4 log

2

+ +

−

=

⎟⎠

⎜ ⎞

⎝

+ ⎛

− +

+

=

−

− +

+

=

+

−

Z E

f

Z E Z

E f

E Z

Z E

f

o EC

o o

o o

β β

Comparative Half Lives

• 

O to

N

–  positron decay –  Q=1.81 MeV –  T

=70.6 s

•  Log f

= 1.83, log t = 1.84

•  Log ft=3.67

2 2

3 81 . log1 ) 1 7 ( 009 . 0 ) 7 ( 007 . 0 79 . 0 81 . 1 log 0 . 4 log

log 3 ) 1 (

009 . 0 007

. 0 79 . 0 log

0 . 4 log

⎟⎠

⎜ ⎞

⎝

+ ⎛

− +

+

=

⎟⎠

⎜ ⎞

⎝

+ ⎛

− +

+

=

+ +

β β

f

Z E Z

E

f _o ^o

Logft calculations

16

coming  from  experiment

t f

ft log log

log = +

coming  from  calculations

Decay  

Mode Type   ΔI  (π_iπ _f) ^{log  f}

β-

EC + β+

allowed 0,  +1  (+)

β-

EC + β+

1^st-­‐‑forb   unique

"

2  (-­‐‑)

−

log f

) /

log(

log f

+ f

f

) log( f

+ f

N.B.  Gove  and  M.  Martin,  Nuclear  Data  Tables  10  (1971)  205

)]

/(

)

log[( f

+ f

f

+ f

Log ft values

Log ft calculation

•  ²¹² Bi beta decay

•  Q = 2.254 MeV

•  T _1/2 = 3600 seconds

–  64 % beta branch – λ

=1.22E-4 s

–  T

Beta =5625 seconds

•  Log f=3.73; log t=3.75

•  Log ft=7.48

254 .

2 log ) 1 84 ( 005 .

0 ) 84 ( 02 . 0 78 . 0 254 .

2 log 0 . 4 log

log ) 1 (

005 .

0 02

. 0 78 . 0 log

0 . 4 log

−

− +

+

=

−

− +

+

=

−

−

β β

f

E Z

Z E

f

Log ft data

•  What drives the changes in the log ft values for

Hg?

19

q   ENSDF  analysis  program  LOGFT  –  both  Windows  &  Linux  distribution

hRp://www.nndc.bnl.gov/nndcscr/ensdf_pgm/analysis/logft/

q   LOGFT  Web  interface  at  NNDC

Log f

20

P

T T t

β

β

exp 2 / 1 2

/

1

=

≡

)]

( )

(

[ I out I in

P

i

= η −

β

∑ ⁺

=

i

Ti i

tot

out in I

I ( / )

( 1 α )

2 2

1

) 2 ( )

1 ) (

2 1

( δ

α δ α α

+

= +

+ M E

E

M ^{T T}

T

q   What  we  want  to  know  accurately ü  T

,  I

,  α

 &  δ

) 10 ( 78 . 0 ) 619 416

( + =

Itot

) 16 ( 086 . 0 ) 721 521

( + =

Itot

In

Out

=  0.69(10) (net)

31 . 6 log

] [ 10 056

. 2 0022

.

0 → = ×

→ =

= t s t

η ^{→ log f = 2 . 386 → log ft = 8 . 7}

Log t

21

q   There  are  only  a  few   cases  where  unambiguous   assignment  can  be  made q   “pandemonium  effect”  –   neutron  rich  nuclei  –  log  ft   is  a  just  lower  limit!

q   needs  to  know  the  decay   scheme  and  its  properties   accurately!

~1000  cases

Rules for spin/parity assignments

22

B.  Singh,  J.L.  Rodriguez,  S.S.M.  Wong  &  J.K.  Tuli

~3900  cases  -­‐‑>  gives   centroids  and  widths

Log ft values –latest review

PART2

Beta decay and nuclear astrophysics

Nucleosynthesis is a gradual, still ongoing process:

Life of a star

Death of a star

(Supernova, planetary nebula) Interstellar

medium

Remnants (White dwarf,

neutron star, black hole)

Nucleosynthesis:

Stable burning

Nucleosynthesis:

Explosive burning H, He

continuous enrichment, increasing metallicity

Condensation

M~10^4..6 M_o 10⁸ y

10^6..10 y

M > 0.7M_o Star formation

Dust mixing

Nucleosynthesis

Dense clouds Big Bang

Creation of the elements

protons

neutrons

Mass known Half-life known nothing known

Big Bang

Cosmic Rays stellar burning

rp process

p process

s process

r process Most of the heavy elements (Z>30) are

formed in neutron capture processes, either the slow (s) or rapid (r) process

np process

Light element primary process LEPP

Nucleosynthesis

Ba: s-process Eu: r-process

Ba

Eu

Contribution of the diff. processes to the solar abundances

s-process:

Astrophysical model p-process:

Astrophysical model r-process:

Abundance of enriched-r-process

star

LEPP = solar-s-p-r

Contribution of different processes

Element formation beyond iron involving rapid neutron capture and radioactive decay

Waiting point (n,γ) - (γ-n) equilibrium

β -decay Seed

High neutron density

G(Z,A)

~ nnT-3/2 G(Z,A+1)

e

Y(Z,A+1)

Waiting point approximation

R-process basics

Masses:

•  Sn location of the path

•  Q_β, Sn theoretical β-decay properties, n-capture rates

β-decay half-lives

(progenitor abundances, process speed)

Fission rates and distributions:

•  n-induced

•  spontaneous

•  β-delayed β-delayed n-emission

branchings

(final abundances)

n-capture rates

Smoothing progenitor

abundances during freezeout

Seed production rates

ν-physics ?

Nuclear physics in the r-process

Known Pn-Values

•  Practically all NEW nuclei, are expected to be neutron emitters!

stability

P_n β-delayed neutron

emission probability

P_n: Moeller et al PRC67(2003)

The knowledge we have on nuclear structure and dynamics is based on a b o u t 3 0 0 0 n u c l e i , whereas still more than 5000 new nuclei must exist.

Almost all these new

nuclei are expected to be neutron emitters, and hence, an understanding of this property and the involved technique

becomes of pivotal impotance for NS and future studies.

Beta-delayed neutron emission

Conditions for delayed neutron emission

è neutron emission competes and can dominate over γ-ray de-excitation The process will dominate far from stability on the n-rich side.

Pn è gives info on decay above Sn è stringent test on β-strength function

* Sn < Q_β

* decay to states above Sn

148Cs

148Ba

148La

T_1/2= 146 ms

T_1/2= 612 ms

147Ba

β- β^-

β^- n

P_n= 20%

T_1/2= 1.26 s

Pn x 10 Pn / 10 Pn x 10 Pn x 0.4

N=126

In  134   138  ms   βn,  β2n  

During  „Freeze-­‐out“:    

detour  of  β-­‐decay  chains   ð    r-­‐abundance  changes  

During  „Freeze-­‐out“:    

enhancement  of  neutron  flux   ð    r-­‐abundance  changes  

Impact on r-process abundances

PART3

Beta decay in n-rich nuclei

-  in-flight fragmentation facilities -  ISOL facilities

-  TAS experiments

N-rich nuclei: short half-lives regime

Nuclei produced by means of relativistic frangmentation/fission of heavy nuclei on thin targets

•  GSI, Riken, MSU, (Ganil)

•  > 50 MeV/u è producton of cocktail beams of many nuclei

•  Use of spectrometers to transport and eparate nuclei of interest è Relatively long decay paths Δt > 150-300 ns

•  Nuclei are then brought to rest in final focal plane and let decay

pros Cons

•  Possibility of studying a set of nuclei AT THE SAME TIME

•  Van be used to study both short- living (ms ) and long living (100s ) nuclei

•  Study mother and daughter decay at same time (if mother nculeus has isomeric states > 1µs)

•  Get informations already with few particles

•  Low production rates

è Diminishing at increasing N/Z ratio

•  Need to run at low rate to distinguish contributions from each nucleus

Experimental technique

* Active, position sensitive, pixelated stopper to correlate implanted ions (mother) with β-decay (daughter).

è stack of several DSSSD to ensure implantation and detect electrons

* Measure γ rays (internal structure) from decays of ns-ms isomeric states in original implanted ion, and/or excited states in daughter nucleus

N-rich nuclei: short half-lives regime

beam

GSI

RIKEN

β

Beta-delayed gammas

Ion-beta correlation techniques:

distinguish implantation and decay within same detector

Implantation-decay correlations with large background

(half lifes similar to the implantation rate):

ü implant-decay time correlation:

active catcher

ü  implant-decay position correlation: granularity ü  implant of several ions:

thickness and area

ü  energy of the implanted ion and the emitted β

* Dual gain pre-amps on DSSSD to get energies of implanted ion and β-particle

* All events time stamped with MHz clock.

GSI RIKEN

* Low gain branch for implanted ions

* High-gain branch for β and α decays

Ion-beta correlation techniques:

conditions

β  and α correlations

Prompt-time γ correlations

Typical Trigger conditions Implantation:

Signal coming from separator

(egs. Last scintillator before stoppers) Decay:

OR signal coming from Si detectors γ rays are usully acquired as SLAVE in both trigger conditions

Additional conditions to be added off-line during data reduction/analysis:

-  Time correlation btw. Identified implantation and subsequent decay requiring also position correlation (neighbour pixels) and maximum

“surviving” time (egs. 3xT_1/2)

-  γ correlation to ensure correct correlation (no bg): delayed γ within

~100-200 ns window

-  Time spectrum using TIMESTAMPS and with γ gate

Silicon PIN Stack

4 x Si PIN DSSD (40⋅40)

• Implantation DSSD:

x-y position (pixel), time

• Decay DSSD:

x-y position (pixel), time

6 x SSSD

(16) Ge

Veto light particles

Beta calorimetry

Beta Counting System (BCS) [MSU/SIMBA@GSI]

Full reconstruction of all quantities: time/gamma/Qvalue

Boron Carbide Shielding Polyethylene

Moderator

BF₃ Proportional Counters

3He Proportional Counters

G. Lorusso, J.Pereira et al., PoS NIC-IX (2007)

Nuclei with β^-decay Nuclei with β-decay AND neutron(s)

P_n-values

Measurement of neutron in “delayed”

coincidence with

β

Implantation station: The Neutron Emission Ratio Observer (NERO)

Sn region

~260 ¹⁰⁰Sn nuclei produced (0.75/h)

~ 126 fully reconstructed decay chains

2.62

Measuring long half-lives

produced implanted

Fragmentation of ²³⁸U beam @ 1GeV/u Ibeam ~ 3*10⁹ pps

Beam extraction 1s, beam cycle 3s

WARNING: long lifetimes and high rates imply a careful study of bg contributions è ion-β correlations : out of beam + ion- β position correlations + ion-β time

correlations

è uncorrelated decays determined from backward-time ion-β correlations

213Pb->²¹³Tl backward ^forward

212Tl

212Pb

211Tl

211Pb

New spectroscopic information in ²¹⁹Po

211-212-213Tl

43

•  Long half-lives è cover many beam repetition cycles

•  High rate è possible double implantations Standard techniques are not available

è numerical fit based on Monte Carlo simulations of the implantation-decay process including experimental

implantation rates and having as free parameters the β decay half life and the β detection efficiency

χ² fits to two independent time correlations:

• Experimental ion-β time-correlated spectra

• Calculated time distribution obtained from Monte-Carlo simulations

Fitting function: ratio of forward/backward time-distribution functions

218Bi:

Benchmark of Analysis

H. de Witte et al., PRC (2004)

Ad-hoc numerical procedure

Important results in heavy mass region

The description of

first-forbidden (ff) transitions using macroscopic statistical models seems a good approach for these nuclei

at variance from N<126 nuclei

FRDM+QRPA and DF3 + QRPA models in agreement with our measurements

G.Benzoni et al., PLB 715 (2012) 293

Nuclei produced by ISOL method, spallation/fission/fragmentation on thick targets, followed by chemical/physical processes to extract desired nuclei

•  High intensity proton beams and beams produced at very low energies (60 keV) [possibility for post-acceleration]

•  Monoisotopical beams sometimes achieved. Impurities due to few contaminant species

ISOL: Isotope Separation On Line

ISOL: Isotope Separation On Line

•  ISOLDE, Ganil, ALTO, Jyvaskyla, SPES….

pros Cons

•  Usually high cross sections

•  No need to re-accelarated beams

•  Usually can accept high rates

•  Study mother and daughter decay at same time (if mother nucleus has isomeric states > 1ms)

•  Short-living nuclei cannot be accessed since they decay in- flight

•  Not all nuclei can be successfully extracted

•  Relatively Long-living nuclei (> 100ms) owing to intermediate processes of effusion and

diffusion

  Laser   1 1

H 2

He

2 3

Li 4

Be 5

B 6

C 7 N 8

O 9 F 10

Ne 3 11

Na 12

Mg 13

Al 14 Si 15

P 16 S 17

Cl 18 Ar 4 19

K 20

Ca 21

Sc 22 Ti 23

V 24 Cr 25

Mn 26 Fe 27

Co 28 Ni 29

Cu 30 Zn 31

Ga 32 Ge 33

As 34 Se 35

Br 36 Kr 5 37

Rb 38

Sr 39

Y 40 Zr 41

Nb 42 Mo 43

Tc 44 Ru 45

Rh 46 Pd 47

Ag 48 Cd 49

In 50 Sn 51

Sb 52 Te 53

I 54 Xe 6 55

Cs 56 Ba * 71

Lu 72 Hf 73

Ta 74 W 75

Re 76 Os 77

Ir 78 Pt 79

Au 80 Hg 81

Tl 82 Pb 83

Bi 84 Po 85

At 86 Rn 7 87

Fr 88 Ra ** 103

Lr 104 Rf 105

Db 106 Sg 107

Bh 108 Hs 109

Mt 110 Ds 111

Rg  

* Lanthanides * 57 La 58

Ce 59 Pr 60

Nd 61 Pm 62

Sm 63 Eu 64

Gd 65 Tb 66

Dy 67 Ho 68

Er 69 Tm 70

Yb

** Actinides ** 89 Ac 90 Th 91

Pa 92 U 93

Np 94 Pu 95

Am 96 Cm 97

Bk 98 Cf 99

Es 100 Fm 101

Md 102 No

TAPE Station systems

0.5 inch Al-coated mylar tape.

Principle of operation

RI beam

Implantation point

Decay point

Each “point” is a measuring point and can be equipped with egs. Ge detectors and Plastic or Si detectors for β particles

Trigger given by implantation signal and β signal

Long-living activity is removed by moving away the tape

In-beam vs TAPE Station systems: figures

In-beam Tape station

•  Low production rates

•  Require little statistics

•  can be used to study both short- living ( ms ) and long living (100s ) nuclei

•  Get informations already with few particles

•  Can focus on single case è Clean signal

•  Usually higher cross-sections

•  Only nuclei T1/2> 100 ms

•  Naturally eliminating bg activity

•  ε_implant ~ 70 %

•  ε_β < 50%

•  ε_γ ~ 15 % (in best case) (**)

•  Ε_implantjj, ~ 100%(*)

•  ε_β ~ 50-60%

•  ε_γ ~ 10 % (**)

(*) provided T1/2 is large otherwise we have losses due to decays “on the way”

(**) of course it depends on many parameters: number of detectors, distance from implantation point, other reactions (prompt-flash in case of in-beam)

€

ft

= constʹ′ 1

M

= constʹ′ 1

B

S

(E) = P

(E)

f (Zʹ′,Q

− E)T

= 1 ft(E)

€

t

= T

P

T

= ln(2)

λ ⁼ τ ^ln(2)

€

B

= 1

2J

+ 1 Ψ

τ

^or στ

Ψ

2

Example:

Co decay from http://www.nndc.bnl.gov/

Feeding:=I

= P

*100 Comparative half-life: ft

€

f (Zʹ′,Q) = const ⋅ F(Zʹ′, p)p²(Q − E_e)²dp

0 p_max

∫

β

Real

situation

Z

A

Z+1

A

γ

γ

2

1

€

f

= I

f

= 0 (I

2

= I

)

•  Ge detectors are conventionally used to construct the level scheme populated in the decay

• From the γ intensity balance we deduce the β-feeding

€

E_γ

1

€

E_γ

2

The problem of measuring the β-feeding

β

Z

A

Z+1

A

γ

γ

2

1

•  What happens if we miss some intensity

€

E_γ

1

€

E_γ

2

€

f

= 0 f

= I

Apparent situation

€

Single γ ^~ ε

Coinc γ ₁ γ ₂ ^~ ε ₁ ε ₂

The problem of measuring the β-feeding

.

€

f (t) = E

λ

^N

∑

^(t)

Z

A

Z+1

A

β- decays

Z

A

Z+1

A

β- decays

( )

∑ ( )

∑

=

=

i

i i

i

i i

E E

I E

E E

I E

β γ

β β

β ^,

γ β

E

E overestimation underestimation

Pandemonium effect

Since the gamma detection is the only reasonable way to solve the problem, we need a highly efficient device:

A TOTAL ABSORTION SPECTROMETER

But there is a change in philosophy. Instead of detecting the individual gamma rays we sum the energy deposited by the gamma cascades in the detector.

A TAS is like a calorimeter!

Big crystal, 4π (BaF₂/NaI/HPGe)

f B R d = ) ( ⋅

TAGS measurements

∑ ^{= ⋅}

=

j

j ij

i R f or

d d R f

R is the response function of the spectrometer, R

means the probability that feeding at a level j gives counts in data channel i of the spectrum

The response matrix R can be constructed by recursive convolution:

k jk

j

g R

R ∑

−

=

⊗

=

1 0 j k

b

g

: γ-response for j

k transition R

: response for level k

b

: branching ratio for j

k transition

0 1 2 3

Mathematical formalization by Tain, Cano, et al.

TAGS analysys

β-decay

Ge det

TAS det (NaI(tl)) (Det 1 & det 2)

Tape station Rad. beam

Si det

Det 1: 20 cm diam., 20 cm length, 5 cm hole

Det2: 20 cm diam, 10 cm length LNPI design (St. Petersburg)

TAS experimental setup

•  A large NaI cylindrical crystal 38 cm Ø, 38cm length

•  An X-ray detector (Ge)

•  A β detector

•  Possibility of collection point inside the crystal

Lucrecia : the TAS at ISOLDE (CERN)

(Madrid-Strasbourg-Surrey-Valencia)

T_1/2 = 1098(18) s; Q_β= 5516(6) keV E_β(TAGS) = 931 (10) keV

E_β(JEFF-3.1) = 1595 (75) keV E_γ(TAGS) = 3229 (24) keV E_γ(JEFF-3.1) = 1890 (31) keV

ΔE_β = -664 keV

ΔE_γ = 1339 keV D. Jordan, PhD Thesis, Valencia, 2010

D. Jordan, PRC 87, 044318 (2013)

d and R(b)*f^final

Results of the analysis for

Tc

Conclusions

reasons to study beta decay:

Ø  Access to gross informations on the decay, Half-life, Pn etc.

Ø  First information on excited states far from stability Ø  Spin assignments owing to selection rules

Ø  Access to non-yrast states

Ø  Definition of shapes of daughter nuclei Ø  Connection to mass measurements

Ø  Input for astrophysics and reactor heat calculation….

……many more…