Scott E. Campbell, Georg Bollen, B. Alex Brown, Adam Dockery, Christian M. Ireland, Kei Minamisono, Daniel Puentes, Brooke J. Rickey, Ryan Ringle, Isaac T. Yandow, Kevin Fossez,
Alejandro Ortiz-Cortes, Stefan Schwarz, Chandana S. Sumithrarachchi, Antonio C.C. Villari
We report the first mass measurement of the proton-halo candidate 22Al performed with the low energy beam ion trap facility's 9.4 T Penning trap mass spectrometer
at facility for rare isotope beams. This measurement completes the mass information for the lightest remaining proton-dripline nucleus acheivable with Penning traps. 22Al has
been the subject of recent interest regarding a possible halo structure from the observation of an exceptionally large isospin assymetry [J. Lee et al., large isospin assymetry in
Si22/O22 Mirror Gamow-Teller transitions reveals the halo structure of 22Al,
Phys. Rev. Lett. 125, 192503 (2020).
The measured mass excess value of ME = 18 092.5(3) keV, corresponding to an exceptionally small proton separation energy Sp = 100.4(8) keV, is compatible
with the suggested halo structure. Our result agrees well with predictions from sd-shell USD Hamiltonians. While USD Hamiltonians predict deformation in the 22Al ground state
with minimal 1s1/2 occupation in the proton shell, a particle-plus-rotor model in the continuum suggests that a proton halo could form at large quadrupole deformation. These
results emphasize the need for a charge radius measurement to conclusively determine the halo nature.
Adam Dockery, Kristian König, Jeremy Lantis, Yuan Liu, Kei Minamisono, Skyy V. Pineda, and Robert Powel
Collinear laser spectroscopy experiments were performed on singly charged 45Sc (45Sc II). Fourteen fine-structure transitions in the 3d4s ↔
3d4p configuration were studied for three sets of triplet states, the 3D1, 3D2, 3D3 states in the 3d4s
configuration and the 3F2, 3F3, 3F4, 3D1, 3D2, 3D3
states in the 3d4p configuration. Furthermore, the hyperfine magnetic dipole (A) and the elctric quadrupole (B) coupling constants were determined. Detailed studies
of experimental systematic uncertainties lead to accurate determination of the coupling constants and facilitate comparison with theoretical models, especially for B constants. The
improved experimental uncertainty reveals deviations from available theoretical calculations and suggests the need for further theoretical studies.
Kristian König, Stephen Fritzsche, Gaute Hagen, Jason D. Holt, Andrew Klose, Jeremy Lantis, Yuan Liu, Kei Minamisono, Takayuki Miyagi, Witold Nazarewicz,
Thomas Papenbrock, Skyy V. Pineda, Robert Powel, and Paul-Gerhard Reinhard
Charge radii of neutron deficient 40Sc and 41Sc nuclei were determined using collinear laser spectroscopy. With the new data, the chain of Sc
charge radii extends below the neutron magin number N = 20 and shows a pronounced kink, generally taken as a signature of a shell closure, but one notably absent
in the neighboring Ca, K, and Ar isotopic chains. Theoretical models that explain the trend at N = 20 for the Ca isotopes cannot reproduce this puzzling behavior.
Root-mean-square charge radii are discussed in terms of spherical energy-density functional (EDF) models
corrected for quadrupole deformations. We discuss the specific examples for the isotope shifts of the calcium
isotopes and the isotonic shift between tin and cadmium.
Robert Powel, B. Alex Brown, J. D. Holt, Andrew Klose, Kristian König, Jeremy Lantis, Kei Minamisono, T. Miyagi, and Skyy Pineda
The hyperfine coupling constants of the proton dripline odd-odd 40Sc nucleus were deduced from the hyperfine
spectrum of the 3d4s3D2 ↔ 3d4p3F3 transition in Sc II,
measured by the bunched beam collinear laser spectroscopy technique. The ground-state magnetic-dipole and electric-quadrupole moments were determined
as μ = +5.57(4)(2)μN and Q = +42(38)(28) e2 fm2, respectively. The magnetic moment is well reproduced
by the additivity rule with magnetic moments of neighboring odd-even nuclei in the vicinity of the doubly magic
40Ca nucleus. An ab initio multishell valence-space Hamiltonian was also employed to calculate the magnetic
moment of 40Sc, which spans across the sd and f p nuclear shells, where we obtained good agreements.
Felix Sommer, Kristian König, Dominic M. Rossi, Nathan Everett, David Garand, Ruben P. de Groote, Jason D. Holt, Phillip Imgram, Anthony Incorvati,
Colton Kalman, Andrew Klose, Jeremy Lantis, Yuan Liu, Andrew J. Miller, Kei Minamisono, Takayuki Miyagi, Witold Nazarewicz, Wilfried Nörtershäuser,
Skyy V. Pineda, Robert Powel, Paul-Gerhard Reinhard, Laura Renth, Elisa Romero-Romero, Robert Roth, Achim Schwenk, Chandana Sumithrarachchi, and Andrea Teigelhöfer
Nuclear charge radii of 55,56Ni were measured by collinear laser spectroscopy. The obtained information
completes the behavior of the charge radii at the shell closure of the doubly magic nucleus 56Ni. The trend
of charge radii across the shell closures in calcium and nickel is surprisingly similar despite the fact that the
56Ni core is supposed to be much softer than the 48Ca core. The very low magnetic moment μ(55Ni) =
-1.108(20) μN indicates the impact of M1 excitations between spin-orbit partners across the N,Z = 28
shell gaps. Our charge-radii results are compared to ab initio and nuclear density functional theory
calculations, showing good agreement within theoretical uncertainties.
Skyy V. Pineda, Kristian König, Dominic M. Rossi, B. Alex Brown, Anthony Incorvati, Jeremy Lantis, Kei Minamisono, Wilfried Nörtershäuser,
Jorge Piekarewicz, Robert Powel, and Felix Sommer
The nuclear root-mean-square charge radius of 54Ni was determined with collinear laser spectroscopy to be R(54Ni) = 3.737(3) fm.
In conjunction with the known radius of the mirror nucleus 54Fe, the difference
of the charge radii was extracted as ΔRch = 0.049(4) fm. Based on the correlation between ΔRch and the
slope of the symmetry energy at nuclear saturation density (L), we deduced 21 ≤ L ≤ 88 MeV. The
present result is consistent with the L from the binary neutron star merger GW170817, favoring a soft
neutron matter EOS, and barely consistent with the PREX-2 result within 1σ error bands. Our result
indicates the neutron-skin thickness of 48Ca as 0.15-0.21 fm.
Robert Powel, MaKenna Koble, Julian Palmes, Nathan Everett, Phillip Imgram, Kristian König, Jeremy Lantis, Kei Minamisono, Wilfried Nörtershäuser, Ryan Parker, Skyy Pineda, Felix Sommer & Andrew Klose
A laser wavelength meter was calibrated to ±1 MHz 1σ using transitions in molecular iodine at around 700 nm, where precise experimental measurements of iodine lines are sparse. Two saturation absorption spectroscopy systems were used to measure and characterize the R(118)(2-8) a10, R(54)(3-9) a1, and P(48)(3-9) a15 hyperfine lines of molecular iodine near 700 nm. The transition frequencies were measured using a frequency comb and used to calibrate the wavelength meter. Additionally, the full hyperfine spectrum of the R(54)(3-9) transition was obtained and fitted using a theoretical model allowing for hyperfine coupling constants to be deduced, which agreed with theoretical values.
Kristian König, Felix Sommer, Jeremy Lantis, Kei Minamisono, Wilfried Nörtershäuser, Skyy Pineda, and Robert Powel
The isotope shifts of the 3d94s3D3→3d94p3P2 transition in the stable even-even nickel isotopes were measured. An improved accuracy was achieved by transforming the systematic contribution of the wavelength-meter-based laser-frequency measurement into a statistical-acting contribution by measuring the same observables at different frequency sets. A detailed King-fit analysis was performed to extract the mass-shift and field-shift parameters, which are crucial for the determination of the charge radii of short-lived isotopes from recently measured isotope shifts. A critical dependence of the achievable charge-radius accuracy on the choice of the reference isotope in the King-fit analysis was observed and is discussed.
Kristian König, Kei Minamisono, Jeremy Lantis, Skyy Pineda, and Robert Powel
An approach to determine the kinetic beam energy at the 10-5 level is presented, which corresponds to an improvement by more than one order of magnitude compared with conventional methods. Particularly, collinear fluorescence and resonance-ionization spectroscopy measurements on rare-isotope beams, where the beam energy is a major contribution to the uncertainty, can benefit from this method. The approach is based on collinear spectroscopy and requires no special equipment besides a wavelength meter, which is commonly available. Its advent is demonstrated in a proof-of-principle experiment on a Ni beam. In preparation for the energy measurement, the rest-frame transition frequencies of the 3d94s3D3→3d94p3P2 transitions in neutral nickel isotopes have been identified to be ν0 (58Ni) = 850 343 678 (20) MHz and ν0 (60Ni) = 850 344 183 (20) MHz.
B. A. Brown, K. Minamisono, J. Piekarewicz, H. Hergert, D. Garand, A. Klose, K. König, J. D. Lantis, Y. Liu, B. Maaß, A. J. Miller, W. Nörtershäuser, S. V. Pineda, R. C. Powel, D. M. Rossi, F. Sommer, C. Sumithrarachchi, A. Teigelhöfer, J. Watkins, and R. Wirth
Charge radii of the unstable 36Ca and 38Ca nuclei were recently determined and used to compute differences in charge radii between mirror nuclei ΔRch for the 36Ca – 36S and 38Ca – 38Ar mirror pairs. Given the correlation between ΔRch and the slope of the symmetry energy L at the nuclear saturation density, we deduce L=5-70 MeV, which rules out a large fraction of models that predict a "stiff" equation of state. This is the most precise determination of L in this model based on electromagnetic probes of nuclear ground states. The determined range is consistent with earlier analyses from both laboratory experiments and astrophysical observations, including the recent detection of gravitational waves from the merger of two neutron stars.
A. J. Miller, K. Minamisono, A. Klose, D. Garand, C. Kujawa, J. D. Lantis, Y. Liu, B. Maaß, P. F. Mantica, W. Nazarewicz, W. Nörtershäuser, S. V. Pineda, P.-G. Reinhard, D. M. Rossi, F. Sommer, C. Sumithrarachchi, A. Teigelhöfer and J. Watkins
One of the most important global properties of the atomic nucleus is its size. Experimentally determined nuclear charge radii carry unique information on the nuclear force and complex dynamics of protons and neutrons moving inside the nucleus. The intricate behaviour of charge radii along the chain of Ca isotopes, including the unexpectedly large charge radius of neutron-rich 52Ca, poses a daunting challenge for nuclear theory. Here we present the measurements of the charge radii of proton-rich isotopes 36,37,38Ca, whose properties are impacted by the interplay between nuclear superfluidity and weak binding. Calculations carried out within nuclear density functional theory show that the combination of a novel interaction and a state-of-the-art theoretical method can successfully explain the behaviour of charge radii from the lightest to the heaviest Ca isotopes. Through this model, we show how the new data on 36,37,38Ca elucidate the nature of nucleonic pairing in weakly bound proton-rich isotopes.
A. Klose, K. Minamisono, A. J. Miller, B. A. Brown, D. Garand, J. D. Holt, J. D. Lantis, Y. Liu, B. Maaß, W. Nörtershäuser, S. V. Pineda, D. M. Rossi, A. Schwenk, F. Sommer, C. Sumithrarachchi, A. Teigelhöfer, and J. Watkins
The hyperfine coupling constants of neutron deficient 37Ca were deduced from the atomic hyperfine spectrum of the 4s2S1/2↔4p2P3/2 transition in Ca II, measured using the collinear laser spectroscopy technique. The ground-state magnetic-dipole and spectroscopic electric-quadrupole moments were determined for the first time as μ = +0.7453(72)μN and Q = –15(11)e2fm2, respectively. The experimental values agree well with nuclear shell-model calculations using the universal sd model-space Hamiltonians versions A and B (USDA/B) in the sd-model space with a 95% probability of the canonical nucleon configuration. It is shown that the magnetic moment of 39Ca requires a larger non-sd-shell component than that of 37Ca for good agreement with the shell-model calculation, indicating a more robust closed subshell structure of 36Ca at the neutron number N = 16 than 40Ca. The results are also compared to valence-space in-medium similarity renormalization group calculations based on chiral two- and three-nucleon interactions.
Jeremy D. Lantis, Kei Minamisono, David Garand, Colton Kalman, Yuan Liu, Andrew Miller and Joel Zuzelski
A pulsed laser system has been installed at the BECOLA facility at NSCL/MSU to develop electronic population manipulation techniques for trapped ions of rare isotopes. A simulation has been developed to evaluate possible optical pumping schemes and estimate expected increase in the population of an energy level used in subsequent laser spectroscopy measurements. Development progress is on time and commissioning tests with stable Zr isotopes are planned.
Y. Liu, E. Romero-Romero, D. Garand, J. D. Lantis, K. Minamisono, D. W. Stracener
Three-step resonance ionization of atomic zirconium using Ti:Sapphire lasers is investigated for the first time. We have located eight new excited states between 41,160 and 41,824 cm-1 that could serve as the intermediate state for the second-step transition. Three-step ionization paths via two of the newly observed states have been studied and numerous high-lying and autoionizing levels are observed. Eight new Rydberg series of odd-parity are identified in the photoionization spectra. The convergence limits of these Rydberg series allow us to determine the first ionization potential of Zr to be 53,507.832(35)stat(20)sys cm-1 with an order of magnitude improvement in uncertainty over the previous measurements. In addition, our measurements for one of the selected three-step paths show that the transitions can be saturated with low to moderate laser powers.
M. Hughes, E. A. George, O. Naviliat-Cuncic, P. A. Voytas, S. Chandavar, A. Gade, X. Huyan, S. N. Liddick, K. Minamisono, S. V. Paulauskas, and D. Weisshaar
The half-life of the 20F ground state was measured using a radioactive beam implanted in a plastic scintillator and recording βγ coincidences together with four CsI(Na) detectors. The result, T1/2 = 11.0011(69)stat(30)sys s, is at variance by 17 combined standard deviations with the two most precise results. The present value revives the poor consistency of results for this half-life and calls for a new measurement, with a technique having different sources of systematic effects, to clarify the discrepancy.
X. Huyan, O. Naviliat-Cuncic, P. Voytas, S. Chandavar, M. Hughes, K. Minamisono, S. V. Paulauskas
The yield of photons produced by electrons slowing down in CsI and NaI was studied with four electromagnetic physics constructors included in the Geant4 toolkit. The subsequent absorption of photons in detector geometries used for measurements of the β spectrum shape was also studied with a focus on the determination of the absorption fraction. For electrons with energies in the range 0.5-4 MeV, the relative photon yields determined with the four Geant4 constructors differ at the level of 10-2 in amplitude and the relative absorption fractions differ at the level of 10-4 in amplitude. The differences among constructors enabled the estimation of the sensitivity to Geant4 simulations for the measurement of the β energy spectrum shape in He decay using a calorimetric technique with ions implanted in the active volume of detectors. The size of the effect associated with photons escaping the detectors was quantified in terms of a slope which, on average, is respectively -5.4 %/MeV and -4.8 %/MeV for the CsI and NaI geometries. The corresponding relative uncertainties as determined from the spread of results obtained with the four Geant4 constructors are 0.0067 and 0.0058.
B. R. Barquest, G. Bollenb, P. F. Mantica, K. Minamisono, R. Ringle, S. Schwarz, C. S. Sumithrarachchi
A radiofrequency quadrupole (RFQ) ion beam cooler and buncher has been developed to deliver bunched beams with low transverse emittance, energy spread, and time spread to the BECOLA collinear laser spectroscopy system at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The beam cooler and buncher contains new features which enhance performance, especially for high count rate beams, as well as simplifying construction, maintenance, and operation. The transverse emittance, energy spread, and time spread of the bunched beam, as well as buncher efficiency are reported, showcasing the capabilities of the BECOLA facility to perform collinear laser spectroscopy measurements with bunched rare isotope beams at NSCL and at the future Facility for Rare Isotope Beams (FRIB).
A. J. Miller, K. Minamisono, D. M. Rossi, R. Beerwerth, B. A. Brown, S. Fritzsche, D. Garand, A. Klose, Y. Liu, B. Maaß, P. F. Mantica, P. Müller, W. Nörtershäuser, M. R. Pearson, and C. Sumithrarachchi
The hyperfine coupling constants of neutron deficient 53Fe were deduced from the atomic hyperfine spectrum of the 3d64s25D4 ↔ 3d64s4p 5F5transition, measured using the bunched-beam collinear laser spectroscopy technique. The low-energy 53Fe beam was produced by projectile-fragmentation reactions followed by gas stopping, and used for the first time for laser spectroscopy. Ground state magnetic-dipole and electric-quadrupole moments were determined as μ = –0.65(1) μN and Q = +35(15) e2fm2, respectively. The multiconfiguration Dirac-Fock method was used to calculate the electric field gradient to deduce Q from the quadrupole hyperfine coupling constant, since the quadrupole coupling constant has not been determined for any Fe isotopes. Both experimental values agree well with nuclear shell model calculations using the GXPF1A effective interaction performed in a full fp shell model space, which support the soft nature of the 56Ni nucleus.
K. Minamisono, D. M. Rossi, R. Beerwerth, S. Fritzsche, D. Garand, A. Klose, Y. Liu, B. Maaß, P. F. Mantica, A. J. Miller, P. Müller, W. Nazarewicz, W. Nörtershäuser, E. Olsen, M. R. Pearson, P. G. Reinhard, E. E. Saperstein, C. Sumithrarachchi, and S. V. Tolokonnikov
Bunched-beam collinear laser spectroscopy is performed on neutron deficient 52,53Fe prepared through in-flight separation followed by a gas stopping. This novel scheme is a major step to reach nuclides far from the stability line in laser spectroscopy. Differential mean-square charge radii δ<r> of 52,53Fe are determined relative to stable 56Fe as δ<r>56,52 = –0.034(13) fm2 and δ<r>56,53 = –0.218(13) fm2, respectively, from the isotope shift of atomic hyperfine structures. The multiconfiguration Dirac-Fock method is used to calculate atomic factors to deduce δ<r>. The values of δ<r> exhibit a minimum at the N = 28 neutron shell closure. The nuclear density functional theory with Fayans and Skyrme energy density functionals is used to interpret the data. The trend of δ<r> along the Fe isotopic chain results from an interplay between single-particle shell structure, pairing, and polarization effects and provides important data for understanding the intricate trend in the δ<r> of closed-shell Ca isotopes.
C. A. Ryder, K. Minamisono, H. B. Asberry, B. Isherwood, P. F. Mantica, A. Miller, D. M. Rossi, R. Strum
The population of low-energy metastable states in Ni I subsequent to charge-exchange reactions and cascade decay was studied for 29.85 keV Ni ions impinging on a sodium vapor. The charge-exchange cross sections were calculated using a semi-classic time-dependent perturbation theory and redistribution of the population via rapid spontaneous decays was simulated. Collinear laser spectroscopy experiments were performed on four emission lines in Ni I to determine populations in low-energy metastable states: 3d94s 3D3 (204.787 cm-1), 3d94s 3D2 (879.816 cm-1), 3d94s 3D1 (1713.087 cm-1) and 3d94s 1D2 (3409.937 cm-1). Fair agreement was obtained between the simulation and experimental results. The low-energy metastable states were preferentially populated after the cascade decay in contrast to weak populations in near-resonant high-energy states in Ni I.
D. M. Rossi, K. Minamisono, H. B. Asberry, G. Bollen, B. A. Brown, K. Cooper, B. Isherwood, P. F. Mantica, A. Miller, D. J. Morrissey, R. Ringle, J. A. Rodriguez, C. A. Ryder, A. Smith, R. Strum, and C. Sumithrarachchi
Background: The systematic trend in mean-square charge radii as a function of proton or neutron number exhibits a discontinuity at the nucleon-shell closures. While the established N = 28 shell closure is evident in the charge radii of the isotopic chains of K through Mn, a similar signature of the N = 20 shell closure is absentin the Ca region. Purpose: The isotope shift between neutron-deficient 36K and 37K was determined to investigate the change ofthe mean-square charge radii across N = 20 in the K isotopic chain. Methods: The D1 atomic hyperfine spectra of 36K and 37K were measured using an optical pumping and subsequent β-decay asymmetry detection technique. Atomic rate equations were solved to fit the resonant lineshape. The result was compared to Skyrme energy-density functional and shell-model calculations. Results: The isotope shift was obtained as δν37,36 = –139(4)(3) MHz. Using a re-evaluated isotope shift, δν39,37 = –264(2)(3) MHz, the isotope shift relative to 39K was determined to be δν39,36 = –403(5)(4) MHz. The differential mean-square charge radius was then deduced as δ<r>39,36 = –0.16(5)(8) fm2. The Skyrme energy-density functional and shell-model calculations overpredict the experimental values below N = 20 and underpredict them above N = 20, and their agreement is marginal. Conclusions: The absence of the shell-closure signature at N = 20 in the K isotopic chain is understoodas a balance between the monopole and the quadrupole proton-core polarizations below and above N = 20, respectively.
D. M. Rossi, K. Minamisono, B. R. Barquest, G. Bollen, K. Cooper, M. Davis, K. Hammerton, M. Hughes, P. F. Mantica, D. J. Morrissey, R. Ringle, J. A. Rodriguez, C. A. Ryder, S. Schwarz, R. Strum, C. Sumithrarachchi, D. Tarazona, and S. Zhao
A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive 37K at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 μs bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 x 105 in resonant photon detection measurements. The hyperfine structure of 37K and its isotope shift relative to the stable 39K were determined using 5 x 104 s-137K ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A(2S1/2) = 120.3(1.4) MHz, A(2P1/2) = 15.2(1.1) MHz, and A(2P3/2) = 1.4(8) MHz, and the isotope shift δν39,37 = –264(3) MHz are consistent with the previously determined values, where available.
Collinear laser spectroscopy was performed on an atomic beam of stable 55Mn. An ion beam of 55Mn+ was generated in an ion source, accelerated to 15 keV, and neutralized via charge-exchange reactions with a Na vapor. A long-lived metastable state of Mn I, near-resonantly populated in the charge-exchange process, was investigated via laser probing in addition to a laser excitation from the ground state in Mn I. The relative population of the Mn I metastable state compared to that of the ground state was found to be 0.7±0.3. A theoretical calculation, which included feeding to the ground state and the metastable state from higher-energy excited electronic states populated in the charge-exchange process, agreed with the present result. The deduced A and B hyperfine coupling constants agreed with literature values, where available.
A collinear laser-spectroscopy (CLS) system in the BEam COoler and LAser spectroscopy (BECOLA) facility was constructed at National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The BECOLA facility will be used to advance measurements of nuclear properties of low-energy rare isotope beams generated via in-flight reactions and subsequent beam thermalization in a buffer gas. The CLS studies at BECOLA will complement laser spectroscopy studies of charge radii and nuclear moments mostly obtained so far at Isotope SeOn Line (ISOL) facilities. Commissioning tests of the CLS system have been performed using an offline ion source to produce stable-ion beams. The tests set the ground work for experiments at the future Facility for Rare Isotope Beams (FRIB) as well as experiments at the current Coupled Cyclotron Facility at NSCL.
A. Klose, K. Minamisono, Ch. Geppert, N. Frömmgen, M. Hammen, J. Krämer, A. Krieger, C.D.P. Levy, P.F. Mantica, W. Nörtershäuser, S. Vinnikova,
The performance characteristics of two charge-exchange cells (CECs) with horizontal and vertical cell configurations were determined by neutralizing a 10-keV rubidium ion beam in a potassium vapor. The neutralization efficiency and the fluorescence line shape of the 5s 2S1/2↔5p 2P3/2 (D2) transition in neutral 85Rb were investigated as a function of the reservoir temperature used to control the potassium vapor density. The CECs exhibited similar neutralization performance and at neutralization efficiencies greater than 25-50% an asymmetric line shape of the rubidium D2 fluorescent signal was observed. The asymmetry was attributed to inelastic channels in the charge-exchange process. The rubidium D2 fluorescence line shape was fitted with a multiple Voigt function, which quantitatively models the inelastic channels. In the present Rb+ + K charge-exchange process, the optimum neutralization efficiency to accurately determine the centroid of the RbD2 resonance line shape was obtained by fitting single Voigt functions to the resonance spectra obtained at neutralization efficiencies where inelastic processes were negligible.
K. Minamisono, G. Bollen, P. F. Mantica, D. J. Morrissey, and S. Schwarz
A facility for collinear laser spectroscopy and beam polarization of exotic nuclei is being developed at NSCL. The facility will make use of thermalized rare isotope beams available at NSCL from projectile fragmentation and in-flight separation with subsequent gas stopping. This system provides access to new and unexplored territory in the nuclear chart and will be implemented at the next generation rare isotope facility. Laser spectroscopy and β NMR/NQR techniques will be utilized to determine nuclear charge radii and nuclear ground state electromagnetic moments as well as for fundamental interaction tests.