laboratory portraitFigure 3. Schematic view of the ISAC facility at TRIUMF sooner after theISAC-II superconducting linear accelerators were installed.“The TRIUMF ISOL Facility,” whichwas presented to the TRIUMF Boardof Management in June 1985. Theproposal recommended
laboratory portraitaccelerated rare isotope beam of 21 Nawas delivered in spring <strong>20</strong>01. Detailsof the ISAC construction history andplans can be found in Ref. [2].ISAC-IIIn the <strong>20</strong>00–<strong>20</strong>05 Five-Year Plan,TRIUMF included plans to upgradeISAC (now called ISAC-I) and beginconstruction of an additional RIBpost-accelerator to 6.5 MeV/u utilizingsuperconducting radio-frequency(SRF) cavities (ISAC-II). ISAC-IIincreased the available energy abovethe Coulomb barrier and expandedthe range of nuclear physics studies[3]. The Canadian federal governmentannounced funding in February<strong>20</strong>00, and $8.7 million CAD ofprovincial funding for civil constructionwas released on June 1, <strong>20</strong>01.The allocated funds allowed work tobegin on the first of three SRF acceleratorsections.Figure 5. Schematic view of theTRINAT neutral atom trap. Shownare the trapping circularly polarizedlasers (beige arrows), the decay betaparticle and detectors, the recoil ionand its multi-channel plate detector,and the implied neutrino direction.Support for completing a secondISAC-II SRF accelerator section and thehigh-energy experimental beamlineswas obtained in the <strong>20</strong>05-<strong>20</strong>10 5YPbudget. Acceleration of 4 He 2+ through asingle SRF module was demonstrated in<strong>20</strong>05, while in April <strong>20</strong>06, 40 Ca 10+ fromOLIS was accelerated through bothISAC-I linear accelerators and all ISAC-II superconducting cavities to a finalenergy of 2<strong>20</strong> MeV (5.5 MeV/u). TheISAC-II era began when the firstradioactive ion beam ( 11 Li) was deliveredto the MAYA experiment in theISAC-II experimental hall on January05, <strong>20</strong>07. Details of the ISAC-IIdesign and construction can be foundin Ref. [3]. Refer to Figure 3 for aschematic view of the ISAC facilitiesand Figure 4 for a plan view of theISAC-II experimental area.Radioactive isotope productionat ISACISOL TargetAt ISAC, radioactive beamsare produced with an intense (up to100 µA), beam of 500 MeV protonsfrom the TRIUMF cyclotron. Thecyclotron has been in continuousoperation since 1975, and broke aweekly beam-delivery performancerecord in <strong>20</strong>09 [4].The ISAC first radioactive beam( 38m K) was delivered to the TRINATexperiment in late 1998. Today, withthe advent of high-powered beamintensities up to about 80 μA on targetis considered normal. In the targethall, the proton beam is delivered toone of two target stations to increaseproduction efficiency. Targets ofroughly <strong>20</strong> g/cm 2 thickness are maintainedat high temperatures by beamand ohmic heating to release reactionproducts into a directly-coupled ionsource. A variety of target materialsFigure 6. b–n correlation parameterfrom the TRINAT 38m K experiment(pure Fermi) compared to othermeasurements with varying degreesof Gamow-Teller admixture.are used, depending on the rare isotopebeam desired.Radioactive Ion sourcesSeveral types of ion sources canbe used with the ISOL production targetsat ISAC - a surface ionizationsource useful for production of lowionizationenergy elements (e.g.,alkali elements Li, Na, K, Rb, Cs, Fr),a specially-designed FEBIAD plasmasource for a broad range of elementsincluding volatile species (e.g., 18 F),and the TRILIS (TRIUMF ResonantIonization Laser Ion Source) sourcecapable of ionizing a wide variety ofisotopes (e.g., 23 Mg). Rare isotopebeam intensities at ISAC are the highestin the world for certain isotopes,without which many important experimentscould not have been performed.e.g., 11 Li intensities of ~5000/sand 21 Na intensities of ~few X 10 9 /son target.Stable Ion SourceISAC also employs several stablebeam ion sources. Originally usedprimarily for accelerator and experimenttuning, they have been used6 Nuclear Physics News, <strong>Vol</strong>. <strong>20</strong>, <strong>No</strong>. 2, <strong>20</strong>10
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