Kieran Flanagan University of Manchester

Since 1995 Before 1995 Z N Key questions Does the ordering of quantum states change? Do new forms of nuclear matter exist? What are limits of nuclear existence? Are there new forms of collective motion? Laser spectroscopy measurements to date 77,78 B. Cheal and K.T. Flanagan, J. Phys. G: Nucl. Part. Phys (2010)

Hyperfine Structure Hyperfine Structure 3s 3p 2 P 3/2 2 P 1/2 2 S 1/2 FjFj FiFi Spin, magnetic and electric moments, all nuclear observables are extracted without model dependence.  IS =  MS +  FS Isotope Shift Isotope Shift ppm shift Changes in nuclear charge radii and sensitive to changes in dynamic nature and deformation as well as volume.

ISOL Primary Beam Light ion (1.4GeV protons) 60keV Ionizer Ions Electromagnetic separator Low-energy High-quality t 1/2 ~ ms chemical properties Limits In-Flight Fragmentation (GSI) Primary Beam 1 GeV/u Electromagnetic Separator High-energy Low-quality All elements t 1/2 ~ μs Low intensities Limits heavy ion 1 GeV/u Thick Target Thin target Gas Catcher+ RFQ Cooler Buncher Low-energy High-quality

B.A. Marsh (RILIS website)

E0E0 E1E1 IP Length of ionizer T=~2000 ⁰C Decay losses J,ћω i J,ћω j Need to satisfy the Flux and Fluence conditions in order to saturate transitions and maximise efficiency. Short duration pulsed lasers (10-20ns) with ~1-10mJ per pulse. CW Laser> 500W (and tight focus) just to saturate the first step! Evacuation time ~100μs Therefore a repetition rate of 10kHz is required for maximum efficiency. ~100mW at 10kHz for resonant steps ~1-5W at 10kHz for quasi resonant steps ~10-20W at 10kHz for non-resonant steps

Relative Frequency (GHz) 68 Cu ΔE=const=δ( 1 / 2 mv 2 )≈mvδv Collinear Concept Applied Doppler tuning voltage For ionic spectroscopy Doppler tuning voltage applied to light collection region PMT Charge exchange Ion Source Separator electrostatic acceleration Energy (eV) nm 287.9nm Cu

Applied Doppler tuning voltage Background due to scattered light PMT Charge exchange Relatively low detection efficiency ~ 1: Large background due to scattered light /s Typical lower limit on yield is 10 6 /s (with a couple of exceptions) ISCOOL z End plate potential Accumulate Release Reacceleration potential PMT 10µs gate eg. 200ms accumulation = 10µs gate width Background suppression ~ min With ISCOOL Counts Tuning Voltage 46 K

Relative Frequency (GHz) 68 Cu ΔE=const=δ( 1 / 2 mv 2 )≈mvδv Collinear Concept Applied Doppler tuning voltage For ionic spectroscopy Doppler tuning voltage applied to light collection region PMT Charge exchange Ion Source Separator electrostatic acceleration Energy (eV) nm 287.9nm Cu In-source + collinear will dramatically reduce the scanning region and therefore the required time to locate resonances.

Combining high resolution nature of collinear beams method with high sensitivity of in-source spectroscopy. Allowing extraction of B factors and quadrupole moments. Relative Frequency (GHz) 68 Cu GHz 30MHz Yu. A. Kudriavtsev and V. S. Letokhov, Appl. Phys. B (1982)

 Charge exchange efficiency into meta stable states  Below saturation on second step  Duty cycle losses due to lasers Total efficiency 1: Ch. Schulz et al., J. Phys. B, 24 (1991) 4831

Relative frequency (MHz) Ion Counts  200 ions per bunch  6 scans  1:30 efficiency  Factor of 1000 increase in detection efficiency. Background due to non- resonant collisional ionization in poor vacuum (10 -5 mbar) ~5 non-resonant ions per bunch

 RIS performed on a fast atomic bunched beam.  Pulsed Amplified CW laser has a resolution which is Fourier limited.  Background events are due to non-resonant collisonal ionization, which is directly related to the vacuum  Very high total experimental efficiency  Neutralization (element dependent)  Ionization efficiency % (no HFS)  Detection efficiency almost 100%  Transport through ISCOOL 70%  Transport to experiment 80-90% 1:30 From Jyvaskyla off-line tests ( K. Flanagan, PhD)

π(1/2+) proton intruder state becomes the ground state in 195At and 185Bi Systematic reduction in energy of the deformed π(1/2+) in isotopes in this region of the chart Suggestion that 199 Fr has I=1/2 + ground state spin with an associated large oblate deformation. 1/2 + 7/2 - 9/2 - 1/2 + 7/2 - 9/ Fr 203 Fr The isomer shifts of 201,203 Fr and their magnetic moments will provide important information to better understand the evolution of nuclear structure in this region.

 Region characterised by reversal in odd-even staggering, which is attributed to presence of octupole-quadrupole deformation.  Also characterised in the interleaving alternating band structure connected by enhance E1 transitions

intruder 1/2+ isomer Region of reflection asymmetry Previous measurements

 Bunched, accelerated ions focused and steered Ions accelerated to scanned velocity and neutralized Remaining ions deflected Pulsed lasers ionize studied atom Resulting ions steered and focused to detector

 From the ISCOOL tests a limit of 10 7 per bunch were trapped and measured on an MCP.  Conservative efficiency of 1:30 (number from Jyvaskyla work) and a pressure of mbar and a high isobaric contamination of 10 7 (expect much lower). Background suppression: Pressure mbar = 1: Detection of secondary electrons by MCP Alpha decay detection allows discrimination of isobaric contamination (50-100cts/s) Limited to ~ 100pps Limited ~5pps With 50% efficiency and signal limited noise regime = 0.3pps

Hyperfine Structure Hyperfine Structure 3s 3p 2 P 3/2 2 P 1/2 2 S 1/2 FjFj FiFi Spin, magnetic and electric moments can dramatically change for the isomeric state.  IS =  MS +  FS Isotope Shift Isotope Shift ppm shift large shift in the transition frequency for the isomeric state compared to the ground state

E0E0 E1E1 IP E2E2 E0E0 E1E1 S1S1 E2E2 S2S2 A B S=ΠS i = S 1 *S 2 With more than three steps S can reach S i of 10 4 is possible

( Ü. Köster et al., NIM B, 160, 528(2000); L. Weissman et al., PRC65, (2000)), I. Stefanescu PRL 98, (2007)) 6 - (g.s.) Cu   3-3-  (g.s.) 68 Cu   70 Cu/ 70 Ga = 50%/50%  lasers ON vs. lasers OFF 70 Cu: 6 -  65% 3 -  23%  ~12% of the total beam 1 +  12%

Cu 70 Cu P. Vingerhoets in preparation

 From the ISCOOL tests limit of 10 7 per bunch were trapped and measured on an MCP.  Conservative efficiency of 1:30 (number from Jyvaskyla work) and a pressure of mbar and a high isobaric contamination of 10 7 (expect much lower). Isobar suppression: Pressure mbar = 1: pps reduces to less than 100pps Typical selection per transition: S i = For two resonant steps S i ~10 7

68 Cu B. Cheal nm 223 nm Second IP 10.1eV 680 nm Ba + Ba 2+ No need to neutralise and therefore more efficient. Non-resonant 2+ production rate should be very low Many step schemes possible (2 step scheme shown here would have S i ~10 7

H H Li Na K K Rb Cs Mg Be B B C C N N O O F F He S S Cl Cu Se Br I I As Sc Ti V V Cr Mn Fe Y Y Co Ni Te Zn Nb Zr Hf Ru Pd Ag Cd La Ce Th Nd Pr Eu Sm Gd Tb Dy Ho Er Yb Tm Pm Lu Mo Hg Pt Au Po Os Re W W Ta Ca Sr Ba Fr Ra Rh Al Ga In Tl Si Ge Sn Pb P P As Sb Bi Ne Ar Kr Xe Rn Ir Tc Ac Pa Possible Scheme exists Accessible Ground state transitions No Scheme possible U U

COMPLIS experiment beam line. Quadrupole Triplet and 34 degree bend retained for CRIS

Basic scheme went through several iterations before converging on the final design. UHV requirements constrained the design and forced the beam line to be ~3m in length

“Railway track” installation Allows one person to open the vacuum system and move chambers.

Delivery of vacuum chambers, Faraday cage, charge exchange cell and installation of pumps.

Vacuum testing, initial bake-out of UHV section reached <5e-9mbar (limit of the gauge) in the interaction region.

Laser launch direction into the beam line ISOLDE beam from HRS

Andreas Krieger, Institute of Nuclear Chemistry - University of Mainz Peak width 0,8  s ~20cm spatial bunch length at A~200

9.11e-9 mbar <5e-9 mbar 7.24e-8mbar 9.64e-7mbar 7.5e-7mbar Results from ISOLDE

100% >70% 30%

Off-line ion source, HV platform and site for future off-line RFQ trap for technique development Alpha detection chamber Windmill design for UHV application ~3m ~2m

Kara Lynch, PhD Project Starting 2010 Possible option: 3 EUROGAM / EUROBALL detectors Fast timing measurement of isomeric states ~2m

M. Hori and A. Dax OPTICS LETTERS 34, 1273 (2009) Tested tuning range 726–941 nm Line width ~6MHz E=50–100 mJ Replacing CW TiSa with a diode laser system (845nm, 300mW) Turn key table top system with minimal interventions during operation. Novel laser system for radioactive ion beam facilities

J. Billowes, B. Cheal, T.E. Cocolios, K.T. Flanagan, D.H. Forest, R. Hayano, M. Hori, T. Kobayashi, F. Le Blanc, O. Levinkron, D. Lunney, K.M. Lynch, G. Neyens, T. Procter, M. Rajabali, S. Rothe, A.J. Smith, H.H Stroke, G. Tungate, W. Vanderheijden, P. Vingerhoets, K. Wendt. Collaboration