TRIUMF Summer Institute, 2015 Precision Measurements of Nuclear - PowerPoint PPT Presentation

TRIUMF Summer Institute, 2015 “Precision Measurements of Nuclear Masses” Klaus Blaum 113 th -25 th July 2015 Klaus.blaum@mpi-hd.mpg.de

Content Motivation for precision mass data 1 Production of short-lived exotic ions 2 How to weigh an atom 3 Nuclear structure and astrophysics 4 Tests of fundamental symmetries 5 Neutrino physics applications 6

Some useful literature Books and review articles: L.S. Brown and G. Gabrielse: Physics of a single electron or ion in a Penning trap; Rev. Mod. Phys. 58, 233 (1986) G. Bollen: Traps for Rare Isotopes, Lecture Notes in Physics, 651, 169-210 (2004) F.G. Major et al.; Charged Particle Traps, Volume I and II Springer, Vol. 37, Berlin (2005) K. Blaum: High-accuracy mass spectrometry with stored ions, Phys. Rep. 425, 1-78 (2006) J. Äystö: Overview of recent highlights at ISOL facilities, Nucl. Phys. A 805, 162c-171c (2008) K. Blaum et al .: Precision atomic physics techniques for nuclear physics with radioactive beams; Physica Scripta T152, 014017 (2013)

1 Atomic masses: Motivation E = mc 2 m n,p ≈ 1 GeV/c 2 = 1.000.000.000 eV/c 2 ≈ 0,0000000000000000000000000017 kg

Fields of applications nuclear structure, (nuclear) astrophysics, astrochemistry, nuclear forces production of heavy elements, atomic and molecular binding energies H 2 fundamental interactions and their symmetries, C 60 particle antiparticle fundamental constants T P C

Atomic and nuclear masses Masses determine the atomic and nuclear binding energies reflecting all forces in the atom/nucleus. = N · + Z · + Z · – binding energy M Atom = N • m neutron + Z • m proton + Z • m electron - ( B atom + B nucleus )/ c 2 δ m / m = 10 -6 – 10 -8 δ m / m < 10 -10

Why measuring atomic masses? Experimental setups δm/m KATRIN-TRAP ≤ 10 -5 General physics & chemistry ≤ 10 -6 Nuclear structure physics - separation of isobars CSRe/ESR ≤ 10 -7 Astrophysics N · + Z · + Z · - separation of isomers TRIGA-TRAP – binding energy ≤ 10 -8 Weak interaction studies ISOLTRAP/TITAN ≤ 10 -9 Metrology - fundamental constants SHIPTRAP Neutrino physics ≤ 10 -10 CPT tests Sources: THe-TRAP Accelerator or reactor based ≤ 10 -11 radioactive beam facilities QED in highly - charged ions PENTA-TRAP and electron beam ion traps. - separation of atomic states CERN IMP/GSI MPIK TRIGA

The liquid drop model Volume Surface Coulomb Symmetry Parity 2 3 e − − − = + + + + 1 / 3 2 4 / 3 1 / 3 2 / ( ) E A a a A Z A a a A I B , Kern Vol Oberf Symm OberfSymm 5 r 0 A = N + Z , neutron number N , proton number Z and elementary charge e Nuclear Radius: R ≈ r 0 A 1/3 Symmetry: I 2 = ( N – Z ) 2 / A 2 C. F. v. Weizsäcker, Zeitschrift der Physik, 96, 431 (1935)

Comparison B nucl : Theory-experiment Nuclear structure effects like shell closures become visible. Nuclear structure effects like shell closures become visible. 1949: The shell model and magic numbers (Göppert-Mayer + Jensen).

Test of nuclear mass models Cs (Z=55)

2 Production of short-lived exotic ions

Radioactive ion beam production Principle Primary beam Secondary beam nuclear ion beam preparation, separation, reaction acceleration/deceleration, ... I 0 I RIB Reaction rate C Cross sections i 1 pb – > 10 b 1 b 10 b R = σ reaction · φ primary · N target 10 11 – 10 15 /cm 2 /s Beam flux Target thickness 0.1 – 100 g/cm 2 RIB intensity I RIB = ε · R 0.1 / day - > 10 12 / s ε = f ( ) Transmission, element, half-life, ionization, ...

Proton-induced reactions (ISOLDE, ISAC) + Spallation 201 Fr protons + + Fragmentation 1 GeV 238 U 11 Li X n + + Fission p 143 Cs Y

ISOLDE target E. Kugler, Hyp. Int. 129, 23-42 (2000). 8 V 500 A Protons 9 V 1000 A http://isolde.web.cern.ch/isolde before after

ISOLDE target robots Target- Target- station 2 station 1 HRS GPS

Ionization possibilities He H ION SOURCE: + SURFACE – hot PLASMA cooled Li Be B C N O F Ne LASER Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Mo Tc Ru Rh Pd Ag Cd Sn Sb Te Xe Rb Sr Y Zr Nb In I Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg 112 113 114 115 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ~80 elements Pa Np Pu Am Cm Bk Cf Es Fm Md No Lr ~1300 isotopes Th U

ISOL principle ISOL: Isotope Separation On-Line

3 How to weigh an atom ν c,1 ν c,1 ν c,2 ν c,2

How to weigh atoms/ions? By capturing and storing of ions and comparing with other masses! Wolfgang Paul Hans Dehmelt (1913 - 1993) (1922 - ... ) Nobel Prize in Physics in 1989 to Hans Dehmelt und Wolfgang Paul „ for the development of the ion trap technique“.

Storage and cooling techniques Penning trap Storage ring Extraction From the FRS Septum- magnet Fast kicker Hexapole- magnets magnet Electron cooler z 0 ESR RF-Accelerating r Quadrupole- Dipole magnet 0 triplet cavity Schottky pick-ups Quadrupole- dublet Gas-target To the SIS 0 0.5 1 cm 0 2.5 5 m particles at nearly rest in space relativistic particles ∗ ion cooling ∗ long storage times ∗ single-ion sensitivity ∗ high accuracy

The Penning trap • Trapping of particle via motion in em field • Strong homog. magnetic field in z direction, particle moves with cyclotron frequency q ω = B c z m → bound in radial direction • Weak, electrostatic quadrupole potential U ρ = − ρ 2 2 DC 1 V ( z , ) ( z ) 2 2 2 d ρ 2 = + 2 2 1 0 ( ) d z Geometry parameter 0 2 2 • Equations of motion in 3D: ·· F = − e 0 ( ∇φ (r) + v × B ) + mr = 0

Equation of motion in a Penning trap F = − e 0 ∇φ (r) + v × B plus Lorentz force: ·· F = − e 0 ( ∇φ (r) + v × B ) + mr = 0 equation of motion: axial oscillation 2 e U 2 e U z or axial ·· ⋅ + = ω z = 0 0   0 0 m z = 0 z m z 0 frequency 2 2 md md 0 0 radial oscillation modified substitution: ω ω ω 2 2 ω = + − cyclotron c c z = + + u x iy frequency 2 4 2 2 ω e ω = · · ω − + = 0 z i u u -  u u  u =  0 B ω ω ω c c 2 2 magnetron m 2 ω = − − c c z frequency − ( ) 2 4 2 = − ω i t u t u e 0

Storage of ions in a Penning trap B U Ion q/m Charge q Mass m The free cyclotron frequency is inverse ω = qB / m proportional to the mass of the ions! c An invariance theorem ω c = ω + + ω - ω c 2 = ω + 2 + ω - 2 + ω z 2 saves the day: L.S. Brown, G. Gabrielse, Rev. Mod. Phys. 58, 233 (1986). K. Blaum, Phys. Rep. 425, 1 (2006).

End of lecture 1 What did we learn? 1) Motivation for precision mass data 2) Liquid drop model and nuclear binding energy 3) Production of radioactive ions 4) Storage of charged particles 5) Penning trap technique What comes next? 1) Manipulation of stored ions 2) Frequency measurement techniques 3) Experimental setup 4) Applications of precision nuclear mass data * Nuclear physics and astrophysics