The Maier-Leibnitz-Laboratory for Nuclear and Particle Physics of LMU Munich and TU Munich

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The Maier-Leibnitz-Laboratory for Nuclear and
Particle Physics of LMU Munich and TU Munich
Nuclear Structure Studies at the MLL Tandem
accelerator
Prof. Dr. Reiner Krücken TU Munich Acting
Director, MLL
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Theory
QCD at shortest distances (elementary particles,
Hadron properties, SUSY, GUT)
Paul (TUM) Schaile (LMU)
Buras (TUM) Fritsch (LMU) Lüst (LMU) Ratz (TUM)
QCD at large distances (Hadrons Nuclei)
Habs (LMU) Krücken (TUM) Paul (TUM)
Ring (TUM) Weise (TUM) Wolter (LMU)
Nuclear astrophysics Cosmology
Habs (LMU) Krücken (TUM) von Feilitzsch (TUM)
Mukhanov (LMU) Ring (TUM)
Methodological and Instrumental Developments
Electroweak interactions
Paul (TUM) von Feilitzsch (TUM)
Buras (TUM) NN(TUM)
Neutrino astronomy
Neutrino properties Dark matter
Applications of nuclear methods Material
analysis Medical applications imaging Radiation
biology
Habs (LMU) Krücken (TUM) Paul (TUM) von
Feilitzsch (TUM)
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DFG Cluster of ExcellenceOrigin and Structure of
the Universe
www.universe-cluster.de
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MLL Tandem laboratory
14 MV Tandem

• Ion sources
• Polarized hydrogen
• Sputter source
• AMS source

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MLL Tandem Nuclear Spectroscopy
Q3D Light-ion transfer reactions with 5 keV
resolution - states in the 2nd and 3rd minimum
in actinides - studies of single-particle
structure - discovery of multitude of 0 states
- investigation of cluster states

• MLL Trap (under construction)
• mass measurements of highly charged ions
• use of gas-ion-catcher
• sympathetic cooling with laser cooled Mg ions
• simultaneaous use of two precision traps
• charge breeding with EBIS

final goal Dm/m 10-10
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Experimental search for 0 states at Q3D

• - (p,t) reactions
• using 25 MeV protons
• 3-5 angles

MLL Uni Köln Yale Bucharest Surrey
2005 (D.A. Meyer)
Plot by Ryan Winkler (Yale)
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Investigating the multiple-humped fission barrier
in Actinides 236U
P. Thirolf, D. Habs, A. Krasznahorkay (Debrecen)

• Transmission resonances in prompt fission
  probability
• coupling of compound states in 1. minimum
• to collective states in 2. and 3. minimum

• rotational substructure of transmission
• resonances resolved in 235U(d,pf)236U, Ed 10
  MeV

• rotational band fit of spectrum and angular
  distribution
• -gt resonance is high-K hyperdeformed

deep third minimum
EIII 2.7(4) MeV
M. Csatlos et al., Phys. Lett. B 615 (2005) 175.
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MLL Tandem MLL Trap Project
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Increased 0 density at the shape phase-transition
154Gd D.A. Meyer et al., PLB 638 (2006), 44-49
and PRC 74 (2006) 044309 152Sm D.A. Meyer, M.
Reithner et al., to be published
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Concept of the MLLTRAP facility

• fusion reaction products from Tandem via buffer
  gas stopping cell (MLL-IonCatcher)
• measurement with Penning trap of highly-charged
  ions
• simultaneous relative measurement of individual
  ions in two precision traps
• (sympathetic) cooling of highly-charged ions with
  laser-cooled Mg ions inside Penning trap and
  Paul trap
• replacement of classical preparatory trap
  inside Penning set-up by A- and Z-selecting
  devices outside Penning trap
• charge breeding with (commercial) EBIS

final goal Dm/m 10-10
Physics Q values for Vud ? MLL
masses from radioactive beams ? GANIL (SPIRAL 2)
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Investigating the multiple-humped fission barrier
in Actinides 236U
transmission resonance spectroscopy
Munich Q3D magnet spectrograph
reaction 235U(d,pf)236U, Ed 10 MeV
focal plane detector energy resolution ca. 5 keV

• (Fission)-lifetimes of states in 3.
• minimum too short for direct
• spectroscopy 10-15s 10-18s

• Transmission resonances in prompt
• fission probability
• coupling of compound states in 1. minimum
• to collective states in 2. and 3. minimum

P. Thirolf, D. Habs, in collaboration with group
of A. Krasznahorkay (Debrecen)
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Investigation of 229mTh
229Th nucleus with lowest-lying excited state in
nuclear physics
recent measurement (3.5 1.0) eV ? (7.6 0.5)
eV 163 11 nm
R. Beck et al., PRL 98 (2007) 142501
isomeric lifetime 1-5 hrs ? extremely sharp
transition
unique perspectives - nuclear metrology
- coherent excitations - potential
improvement in a/a 1010
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search for the 7.6 eV transition _at_MLL

• population via a decay from 233U
• high-precision identification of transition
  energy (optical wavelength)
• later detection of resonance absorption of 163
  nm photon from
• frequency comb (collaboration with T. Udem
  et al., MPQ)

229mTh transition bridge between nuclear
physics and laser physics
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Experiment at Munich Tandem
K. Wimmer (LMU)
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Summary of E0 measurements
154Sm
166Er
K. Wimmer (LMU)
127(60)
? IBA predictions of large E0 strength in
deformed nuclei confirmed
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Increased 0 density at the shape phase-transition
spdf
D.A. Meyer et al., PLB 638 (2006), 44-49
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Expectations for large (unrealistic) Boson numbers
NB30
R4/22.5
R4/23.33
R4/22.0
h0.8
D. Meyer et al.
Further X(5) candidates 150Nd, 152Sm