Production and decay studies of 261 Rf, 262. Db, 265 Sg, and 266 Bh for superheavy element chemistry at RIKEN GARIS

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Nishina Center Hiromitsu Haba for RIKEN SHE Chemistry

Coupling SHE chemistry to a recoil separator 2.

1 Production and decay studies of 261 Rf, 262 Db, 265 Sg, and 266 Bh for superheavy element chemistry at RIKEN GARIS RIKEN Nishina Center Hiromitsu Haba for RIKEN SHE Chemistry Collaboration CONTENTS 1. Coupling SHE chemistry to a recoil separator 2. Production and decay studies of SHE nuclides for chemistry studies with GARIS 3. SHE chemistry behind GARIS 4. Summary and perspectives

2 1. Coupling SHE chemistry to a recoil separator

3 Publications of experimental studies on SHE chemistry Publication year Aqueous Gas Aqueous chemistry: 104, 105, 106 Gas chemistry: , RIKEN JAEA IMP GSI LBNL Dubna 1970 A few pioneering experiments for elements heavier than Sg PSI Orsay 104 Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt 110 Ds 111 Rg 112 Cn 113 Nh 114 Fl

Gas jet transport technique just behind the target 248 Cm( 22 Ne,5n) 265 Sg Chemistry apparatuses Gas or liquid chromatography α/sf spectrometry 22 Ne beam Ta slit He cooling 248 Cm target α spectrum

4 Gas jet transport technique just behind the target 248 Cm( 22 Ne,5n) 265 Sg Chemistry apparatuses Gas or liquid chromatography α/sf spectrometry 22 Ne beam Ta slit He cooling 248 Cm target α spectrum of 265 Sg 265 Sg μm Be 90 kpa C beam stopper He/KCl aerosol and/or reactive gas Counts per 40 kev Problems in the conventional method m Po, At Po, m Po m At, At m Po Target: 480 μg/cm 2 Energy: 120 MeV Dose: Meas.: 105 s, 15 s coll. 265 Sg? Energy / MeV Large amount of background radiations from unwanted reaction products Decrease of gas jet yields due to plasma condition induced by an intense beam m Po

5 Coupling SHE chemistry to a recoil separator Breakthroughs in SHE chemistry Chemical experiments under low background condition Stable and high gas jet transport yield New chemical reactions Proceedings of The 1st Workshop on Recoil Separator for Superheavy Element Chemistry, March 20 21, 2002, Darmstadt, Germany. Recoil Separator for nuclear physics studies Differential pumping section Gas jet transport system Rotating target Beam Evaporation Residues (ERs) Beam dump Gas inlet Focal plane ERs ~0.1 kpa Mylar window ~100 kpa Chemistry apparatus Elastic scattering beam monitor D1 Q1 Q2 D: Dipole magnet Q: Quadrupole magnet D m He(KCl) mm

6 RIKEN GAs filled recoil ion separator GARIS for SHE chemistry Development of a gas jet transport system coupled to GARIS 169 Tm( 40 Ar,3n) 206 Fr; 208 Pb( 40 Ar,3n) 245 Fm [JNRS 8, 55 (2007); EPJD 45, 81 (2007)] 238 U( 22 Ne,5n) 255 No [JNRS 9, 27 (2008)] nat Ge( 19 F,xn) 88 Nb; nat Gd( 19 F,xn) 170 Ta [JRNC 304, 845 (2015)] Production and decay studies of 261 Rf a,b, 262 Db, 265 Sg a,b, and 266 Bh for chemical studies using the GARIS gas jet system 248 Cm( 18 O,5n) 261 Rf a,b [Chem. Lett. 38, 426 (2009); PRC 83, (2011)] 248 Cm( 19 F,5n) 262 Db [PRC 89, (2014)] 248 Cm( 22 Ne,5n) 265 Sg a,b [PRC 85, (2012)] 248 Cm( 23 Na,5n) 266 Bh [under study] Startup of SHE chemistry at RIKEN Synthesis of Sg(CO) 6 [Science 345, 1491 (2014).] Decomposition of Mo(CO) 6 and W(CO) 6 [Radiochim. Acta 104, 141 (2016).] Synthesis of Re(CO) 5 Development of a rapid solvent extraction apparatus for 265 Sg and 266 Bh

7 2. Production and decay studies of SHE nuclides for chemistry studies with GARIS

8 RIKEN RI Beam Factory (RIBF), Wako, Japan D2(10 o ) Q2 Q1 D1(45 o ) Gas filled Recoil Ion Separator (GARIS) Hot Laboratory RIKEN Linear ACcelerator (RILAC)

9 Experimental setup RIKEN GARIS Gas jet transport system Differential pumping section Evaporation Beam from RILAC Residues (ERs) Focal plane Mylar window 50 kpa Rotating target Gas inlet ERs 33 Pa Elastic scattering beam monitor D1(45 o ) Q1 Q2 D2(10 o ) m He/KCl mm Focal plane Si detector Si PIN photodiode Chemistry laboratory MANON for α/sf spectrometry 10 m ERs 15 pairs of Si PIN photodiodes Mylar foil 33 Pa Exhaust mm

Experimental setup RIKEN GARIS Differential pumping section Evaporation Beam

kpa ERs Rotating target Gas inlet ERs 33 Pa Elastic scattering beam monitor

detector Si PIN photodiode Chemistry laboratory MANON for α/sf spectrometry 10 m

10 Experimental setup RIKEN GARIS Differential pumping section Evaporation Beam from RILAC Residues (ERs) Focal plane Gas jet transport system Mylar window 50 kpa ERs Rotating target Gas inlet ERs 33 Pa Elastic scattering beam monitor D1(45 o ) Q1 Q2 D2(10 o ) m Gas jet chamber He/KCl mm Focal plane Si detector Si PIN photodiode Chemistry laboratory MANON for α/sf spectrometry 10 m ERs 100 mm Si PIN photodiodes Mylar foil 33 Pa 248 Cm mm 2 O 3 target Exhaust MANON

11 Production and decay studies of 261 Rf, 262 Db, 265 Sg, and 266 Bh Nuclide 261 Rf a,b (Z=104) 262,263 Db (Z=105) 265 Sg a,b (Z=106) 266,267 Bh (Z=107) Half life 68, 3 s 1) 34 s, 27 s 2) 8.9, 16.2 s 1) 1.7 s, 17 s 4) Reaction 248 Cm( 18 O,5n) 248 Cm( 19 F,5;4n) 248 Cm( 22 Ne,5n) 248 Cm( 23 Na,5;4n) Cross section (nb) 12 3),? 1.5 3),? )? )? Beam energy (MeV) , , 131, 126, 121 Beam intensity (pμa) Cm 2 O 3 target (μg/cm 2 ) 280, , 290, , , 260, 270 Magnetic rigidity (Tm) GARIS He (Pa) GARIS transmission (%) 7.8± ± RTC Mylar window (μm) Honeycomb grid (%) 78/ /84 78 Gas jet He (kpa) Chamber depth (mm) He flow rate (L/min) KCl generator ( o C) / MANON step interval (s) 30.5, , , 8.5, ) Düllmann and Türler, PRC 77, (2008). 2) Firestone and Shirley, Table of Isotopes, 8th ed. (Wiley, New York, 1996). 3) Nagame et al., JNRS 3, 85 (2002). 4) Wilk et al., PRL 85, 2697 (2000). 5) Morita et al., JSPS 78, (2009).

12 Production and decay studies of 261 Rf, 262 Db, 265 Sg, and 266 Bh Nuclide 261 Rf a,b (Z=104) 262,263 Db (Z=105) 265 Sg a,b (Z=106) 266,267 Bh (Z=107) Half life 68, 3 s 1) 34 s, 27 s 2) 8.9, 16.2 s 1) 1.7 s, 17 s 4) Reaction 248 Cm( 18 O,5n) 248 Cm( 19 F,5;4n) 248 Cm( 22 Ne,5n) 248 Cm( 23 Na,5;4n) Cross section (nb) 12 3),? 1.5 3),? )? )? Production cross section and excitation function Beam energy (MeV) , , 131, 126, 121 Beam intensity Effec ve (pμa) produc on 7 of SHE 4 RIs with extremely 3 low Cm 2 O 3 target production (μg/cm 2 ) yields 280, , 290, , , 260, 270 Magnetic rigidity (Tm) Long term experiments with cost accelerators GARIS He (Pa) GARIS transmission (%) 7.8± ± Decay properties such as E RTC Mylar window (μm) α and T 1/ Honeycomb Unambiguous grid (%) 78/84 assignment 84of SHEs to 72/84 derive their 78 Gas jet chemical He (kpa) properties Chamber depth (mm) T He flow rate 1/2 : Direct measure for chemical constants such as (L/min) KCl generator equilibrium ( o C) constant 620 and 620 adsorption 600/605 enthalpy 620 MANON step interval (s) 30.5, , , 8.5, ) Düllmann and Türler, PRC 77, (2008). 2) Firestone and Shirley, Table of Isotopes, 8th ed. (Wiley, New York, 1996). 3) Nagame et al., JNRS 3, 85 (2002). 4) Wilk et al., PRL 85, 2697 (2000). 5) Morita et al., JSPS 78, (2009).

13 Production and decay studies of 261 Rf, 262 Db, 265 Sg, and 266 Bh 248 Cm( 22 Ne,5n): 180/200 pb 8.84 (I ɑ = 91/9), SF (b 50) 248 Cm( 18 O,5n): 12/11 nb ~0.5 min 1 ( 261 Rf a ) (I ɑ = 83), (I ɑ = 17) ~1 h 1 ( 265 Sg a,b ) 8.28, SF (b < 13) 257 No 24.5 s 261 Rf 68 s 2.6 s 8.51 (18) 265 Sg 8.5 s 14.4 s 8.69 (I ɑ = 20/80) SF ( 51) SF (82) Preliminary 8.46 (I ɑ = 70), 8.68 (I ɑ = 30) (I ɑ = 20), (I ɑ = 46), (I ɑ = 25), (I ɑ = 9) 248 Cm( 23 Na,5n): 57 pb ~5 d 1 ( 266 Bh) 248 Cm( 19 F,5n): 2.1 nb ~5 h 1 ( 262 Db) Db 34 s EC (b = 2.6) SF (b = 52) 258 Lr 3.5 s 266 Bh 10.0 s Haba et al., Chem. Lett. 38, 426 (2009). Haba et al., Phys. Rev. C 83, (2011). Haba et al., Phys. Rev. C 85, (2012). Murakami et al., Phys. Rev. C 88, (2013). Haba et al., Phys. Rev. C 89, (2014). Haba, EPJ Web of Conferences 131, (2016). Pre separated SHEs are ready for chemistry experiments at GARIS.

14 3. SHE chemistry behind GARIS

15 (a) Carbonyl complex of SHEs Synthesis of the first organometal SHE compound, Sg(CO) 6 J. Even et al., Science 345, 1491 (2014). O C Metal carbon bond stability in Sg(CO) 6 O C Decomposition studies First Bond Dissociation Enthalpy Mo(CO) 6, W(CO) 6 and Sg(CO) 6 at GARIS Usoltsev et al., Radiochim. Acta 104, 141 (2016). Eichler et al. Basic studies on syntheses of carbonyl complexes of Bh, Hs, and Mt Adsorption enthalpy on Teflon/quartz and chemical yields Tc(CO) 5 with a 252 Cf SF source at IMP Wang et al., Phys. Chem. Chem. Phys. 17, (2015). Ru(CO) 5 and Rh(CO) 4 with a 252 Cf SF source at IMP Cao et al., Phys. Chem. Chem. Phys. 18, 119 (2016). Re(CO) 5 with GARIS Wang et al. RIKEN Accel. Prog. Rep. 50 (in press). (b) Aqueous chemistry of the heaviest elements Mo Tc Ru Rh 6 W Re Os Ir 7 Sg Bh Hs Mt Development of a rapid solvent extraction apparatus for the heaviest SHEs Komori et al. RIKEN Accel. Prog. Rep. 50 (in press). O C Sg C O O C C O

16 4. Summary and perspectives The gas jet transport system was installed in GARIS. Production and decay properties of 261 Rf, 262 Db, 265 Sg, and 266 Bh were investigated using the GARIS gas jet MANON system. Pre separated 261 Rf, 262 Db, 265 Sg, and 266 Bh are ready for chemistry experiments. Synthesis of the first organometal compounds of SHE, Sg(CO) 6, is successful. Syntheses of carbonyl complexes of Tc, Ru, Rh, and Re are under study for Bh, Hs, and Mt carbonyls. A rapid solvent extraction apparatus is under development for the aqueous chemistry of 265 Sg and 266 Bh. RILAC will be upgraded in GHz SC ECR and SC QWR Beam intensity: x 5 10 Developments of actinide targets: 248 Cm, 243 Am, 244 Pu Rf, Db, Sg, and Bh chemistry with larger production yields: x 3 5 Chemistry of 283 Cn, 284 Nh, and 288,289 Fl

RIKEN GARIS for Superheavy Element Chemistry

RIKEN GARIS for Superheavy Element Chemistry Nishina Center, RIKEN Hiromitsu Haba CONTENTS 1. Introduction 2. Present status of GARIS 2.1. Developments in 2008 Rotating 248 Cm target and new gas-jet chamber