A concept for continuously tunable titanium-sapphire (Ti:Sa) lasers using dispersion prisms is under investigation for the ARIEL (Advanced Rare IsotopE Laboratory) laser ion source at TRIUMF ...(Canada’s particle accelerator center). Wavelength selection for pulsed Ti:Sa lasers used in hot cavity laser resonance ionization spectroscopy is usually done with birefringent filters (BRFs) and etalons or diffraction gratings. For resonance ionization spectroscopy a laser system allowing a continuous wavelength scan is necessary. Tunable lasers based on BRFs and etalons have high output powers however require synchronized optimization for continuous laser wavelength scans and are therefore laborious to use in scanning applications. Diffraction grating tuned lasers can provide continuous wavelength scan over 200 nm range but typically have lower output laser power due to the grating deformation under high pumping power. Aiming to overcome both shortcomings a laser design based on prisms as dispersing element has been revisited. Simulations on the beam path and optical reflectivity are done which show that these losses can be minimized to around 0.04 % for a tuning range from 700 nm up to 920 nm. Further improvement on the tuning range and reduction on the linewidth will be pursued.
In the search of efficient laser resonance ionization schemes and optimal source parameters, offline laser ion source development is of importance for successful online radioactive beam delivery. An ...overview and update on recent TRIUMF’s resonance ionization laser ion sources (TRILIS) offline developments is presented. This includes titanium-sapphire (Ti:Sa) laser development and the investigation of the laser ionization efficiency dependence on source temperature and laser polarization.
Hot cavity resonant ionization laser ion sources (RILIS) provide a multitude of radioactive ion beams with high ionization efficiency and element selective ionization. However, in hot cavity RILIS ...there still remains isobaric contamination in the extracted beam from surface ionized species. An ion guide-laser ion source (IG-LIS) has been implemented at TRIUMF’s isotope separator and accelerator (ISAC) facility that decouples the hot isotope production region from the laser ionization volume. A number of IG-LIS runs have been conducted to provide isobar free radioactive ion beams for experiments. Isobar suppression of up to 10
6
has been achieved, e.g. for Mg, Cd, Ga and other isotopes, IG-LIS however, still suffers from an intensity loss of 50-100× as compared to hot cavity RILIS. The work towards operating the IG-LIS in an optimized fashion and possible design improvements to the operational prototype for efficient and robust (radiation hard) on-line operation and recent SIMION ion optics simulation results as well as the ongoing development status of the IG-LIS are presented.
Resonance laser ionization spectroscopy of selenium Li, Ruohong; Liu, Yuan; Mostamand, Maryam ...
Spectrochimica acta. Part B, Atomic spectroscopy,
January 2021, 2021-01-00, 20210101, 2021-01-01, Letnik:
175, Številka:
C
Journal Article
Recenzirano
Odprti dostop
Photoionization spectra of Se have been studied by step-wise resonance laser ionization. The Rydberg series 4s24p3(4S)np3P0,1,2 and 4s24p3(4S)np5P1,2,3 were measured via different excitation schemes. ...Using the Rydberg series 4s24p3(4S)np3P2 with n = 15–49, the ionization potential of Se was determined with improved precision to 76,658.15(2)stat(4)sys cm−1, which resolved the discrepancy in previous literatures. Autoionizing (AI) spectra between the IP and two neighboring converging limits of the Se ionic states 4s24p3(2D3/2) and 4s24p3(2D5/2) were obtained. In total eight AI Rydberg series have been observed, measured and assigned.
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•Stepwise resonance ionization spectroscopy of Se I with Ti:Sapphire lasers.•The ionization potential (IP) of Se is refined to be 76,658.15(2)stat(4)sys cm−1.•New members of odd-parity autoionizing series 4s24p3(2D3/2)nd3Do, ns3Do.•New members of odd-parity AI series 4s24p3(2D5/2)nd3Do, ns3Do, nd3So, nd3Po.•Six Rydberg series 4s24p3(4S)np3P0,1,2 &4s24p3(4S)np5P1,2,3 with 54 new levels.
Using TRIUMF's off-line laser ion source test stand with a system of tunable titanium sapphire lasers, the polarization dependence of laser resonance ionization has been investigated using beryllium. ...A significant polarization dependence was observed for the excitation path 1S0 → 1P1∘ → 1S0, which are typical transitions for alkaline-earth and alkaline-earth like elements. This polarization dependence was further verified on Be radioactive isotopes at TRIUMF's isotope separator and accelerator facility (ISAC). Laser polarization was proven to be an important parameter in operating resonance ionization laser ion sources (RILIS).
The polarization spectroscopy was performed off-line both on the 2p2 1S0 autoionizing (AI) state and high-n Rydberg states of the 2sns1S0 and 2snd1D2 series. The energy of the 2p2 1S0 AI state and ionization potential (IP) of beryllium were extracted as 76,167(6) cm−1 and 75,192.59(3) cm−1. Polarization spectroscopy can be used to determine the J values of newly found states in in-source spectroscopy of the complex/radioactive alkaline-earth like elements such as Ra, Sm, Yb, Pu and No.
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•Polarization-dependent laser resonance ionization of Be in hot-cavity ion sources•Polarization spectroscopy on the 2p2 1S0 AI state and 2sns1S0 and 2snd1D2 series•2p2 1S0 autoionizing state energy measured to be 76,167(6) cm−1•Ionization potential of Be measured to be 75,192.59(3) cm−1•Polarization dependence observed for 9–11 Be isotopes in hot-cavity ion sources.
A continuously tunable titanium:sapphire (Ti:Sa) laser self-seeded by an extended grating cavity was demonstrated and characterized. By inserting a partially reflecting mirror inside the cavity of a ...classic single-cavity grating laser, two oscillators are created: a broadband power oscillator and a narrowband oscillator with a prism beam expander and a diffraction grating in Littrow configuration. By coupling the grating cavity oscillation into the power oscillator, a power-enhanced narrow-linewidth laser oscillation is achieved. Compared to the classic grating laser, this simple modification significantly increases the laser output power without considerably broadening the linewidth. With most of the oscillating laser power confined inside the broadband power cavity and lower power incident onto the grating, the new configuration also allows higher pump power, which is typically limited by the thermal deformation of the grating coating at high oscillation power.
Using TRIUMF's off-line laser ion source test stand with a system of tunable titanium sapphire lasers, the polarization dependence of laser resonance ionization has been investigated using beryllium. ...A significant polarization dependence was observed for the excitation path \(^1\)S$_0$$\rightarrow$$^1\(P\)^{\circ}_1$$\rightarrow$$^1\(S\)_0\(, which are typical transitions for alkaline and alkaline-like elements. This polarization dependence was further verified on Be radioactive isotopes at TRIUMF's isotope separator and accelerator facility (ISAC). Laser polarization was proven to be an important parameter in operating resonance ionization laser ion sources (RILIS). The polarization spectroscopy was preformed off-line both on the 2p\)^2\( \)^1\(S\)_0\( autoionizing (AI) state and high-\)n\( Rydberg states of the \)2sns\( \)^1S_0\( and \)2snd\( \)^1D_2\( series. The energy of the 2p\)^2\( \)^1\(S\)_0\( AI state and ionization potential (IP) of beryllium were extracted as 76167(6)~cm\)^{-1}\( and 75192.59(3)~cm\)^{-1}\(. Polarization spectroscopy can be used to determine the \)J$ values of newly found states in in-source spectroscopy of the complex/radioactive alkaline-like elements such as Ra, Sm, Yb, Pu and No.
A concept for continuously tunable titanium-sapphire (Ti:Sa) lasers using dispersion prisms is under investigation for the ARIEL (Advanced Rare IsotopE Laboratory) laser ion source at TRIUMF ...(Canada's particle accelerator center). Wavelength selection for pulsed Ti:Sa lasers used in hot cavity laser resonance ionization spectroscopy is usually done with birefringent filters (BRFs) and etalons or diffraction gratings. For resonance ionization spectroscopy a laser system allowing a continuous wavelength scan is necessary. Tunable lasers based on BRFs and etalons have high output powers however require synchronized optimization for continuous laser wavelength scans and are therefore laborious to use in scanning applications. Diffraction grating tuned lasers can provide continuous wavelength scan over 200 nm range but typically have lower output laser power due to the grating deformation under high pumping power. Aiming to overcome both shortcomings a laser design based on prisms as dispersing element has been revisited. Simulations on the beam path and optical reflectivity are done which show that these losses can be minimized to around 0.04 % for a tuning range from 700 nm up to 920 nm. Further improvement on the tuning range and reduction on the linewidth will be pursued.
A continuously tunable titanium:sapphire (Ti:Sa) laser self-seeded by an extended grating cavity was demonstrated and characterized. By inserting a partially reflecting mirror inside the cavity of a ...classic single-cavity grating laser, two oscillators are created: a broadband power oscillator, and a narrowband oscillator with a prism beam expander and a diffraction grating in Littrow configuration. By coupling the grating cavity oscillation into the power oscillator, a power-enhanced narrow-linewidth laser oscillation is achieved. Compared to the classic grating laser, this simple modification significantly increases the laser output power without considerably broadening the linewidth. With most of the oscillating laser power confined inside the broadband power cavity and lower power incident onto the grating, the new configuration also allows higher pump power, which is typically limited by the thermal deformation of the grating coating at high oscillation power.
Background: Knee osteoarthritis is the most degenerative joint disease and can consequently cause a defect in balance control. Controlling balance is necessary to prevent physical and psychological ...damage. The current study investigated the effects of the Mulligan mobilization technique on static and dynamic balances in patients with moderate to severe knee osteoarthritis. Methods: In a randomized controlled clinical trial, 31 patients with moderate to severe knee osteoarthritis were selected and then randomly assigned to two groups of treatment (16 patients) and control (15 patients). Static and dynamic balances and pain score were evaluated in these patients once before and once after 10 sessions of treatment. Independent and paired t-tests were used for statistical analysis. The level of statistical significance was set at p<0.05. Results: Pain decreased significantly in both groups after intervention (p<0.001). The treatment group experienced significantly greater reduction in pain than the control group (p=0.005). A significant improvement was found in both static (p=0.01) and dynamic (p=0.006) balance in the treatment group after the intervention. Additionally, the improvement in static (p=0.04) and dynamic (p=0.02) balance was greater in the treatment group compared to the control group. Conclusions: The results of the present study reveal that Mulligan mobilization technique can improve balance in patients with moderate and severe knee osteoarthritis.
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