Development of a rapid solvent extraction apparatus coupled to the GARIS gas-jet transport system for aqueous chemistry of the heaviest elements Y. Komori 1, H. Haba 1, K. Ooe 2, D. Kaji 1, Y. Kasamatsu 3, H. Kikunaga 4, A. Mitsukai 5, K. Morimoto 1, R. Motoyama 2, J. P. Omtvedt 6, Z. Qin 7, D. Sato 2, N. Sato 1, Y. Shigekawa 3, T. Tanaka 1, A. Toyoshima 5, K. Tsukada 5, Y. Wang 7, K. Watanabe 1, S. Wulff 6, S. Yamaki 1, S. Yano 1, and Y. Yasuda 3 1 RIKEN Nishina Center, 2 Grad. School of Sci. and Technol., Niigata Univ., 3 Grad. School of Sci., Osaka Univ., 4 ELPH, Tohoku Univ., 5 ASRC, JAEA, 6 Univ. Oslo, 7 IMP
Introduction: Aqueous chemistry of SHEs Gas phase: Z = 104 108, 112 114 Liquid phase: Z = 104 106 Most of the aqueous chemistry of SHEs have been performed using a batch-wise column chromatography apparatus (ARCA) with Si detectors. Nuclide Half-life (s) Production rate* (atoms/h) 261 Rf a 68 420 262 Db 34 70 265 Sg a,b 8.5, 14.4 12 266 Bh 10.0 1.7 * 248 Cm target thickness: 300 μg/cm 2 ; Beam intensity: 2 pμa Pioneering cation-exchange studies of Sg in HNO 3 /HF and HNO 3 Schädel et al., Radiochim. Acta 77, 149 (1997).; Radiochim. Acta 83, 163 (1998). Decay loss during aerosol collection and α-source preparation (~30 s) Low detection efficiency: eff.(α) = ~30% eff.(α-α) = ~9%; eff.(α-α-α) = ~3% A huge amount of background radioactivities of by-products Requirements for the aqueous chemistry studies of Sg and Bh Continuous, rapid, and efficient chemistry apparatus Low-background condition for α/sf detection 1
RIKEN GARIS gas-jet system RIKEN GARIS Gas-jet transport system Differential pumping section Evaporation Beam from RILAC Residues (ERs) Beam dump Gas inlet Focal plane Mylar window 50 kpa ERs Rotating target 33 Pa Elastic scattering beam monitor D1 Q1 Q2 Haba et al., Chem. Lett. 38, 426 (2009). 0 D2 1 2 m He/KCl 0 100 mm By-products are removed almost completely. Production and decay studies of 265 Sg a,b and 266 Bh were successfully performed: 248 Cm( 22 Ne,5n) 265 Sg a,b Haba et al., Phys. Rev. C 85, 024611 (2012). 248 Cm( 23 Na,5n) 266 Bh Haba et al., APSORC 17, A-049 Pre-separated 265 Sg a,b and 266 Bh are ready for the chemistry experiments at GARIS. 2
Continuous and rapid solvent extraction apparatus coupled to the GARIS gas-jet system GARIS gas-jet system He/KCl aerosols 265 Sg a,b, 266 Bh Membrane DeGasser (MDG) Gas out Flow Solvent Extractor (FSE) Membrane filter Organic phase () Membrane filter Photomultiplier tube Mylar window Irradiation room Aqueous solution () Chemistry laboratory Teflon capillary (i.d. = 0.5 mm) Phase separator Liquid scintillator Liquid scintillation α/sf detectors Continuous dissolution, solvent extraction, and radiation detection Minimization of decay loss of 265 Sg a,b and 266 Bh Efficient α/sf detection with LS: eff.(α-α/sf) = ~100% By using this apparatus, we can expect 60 100 times larger event rate of 265 Sg a,b and 266 Bh than those by using the conventional apparatus. 3
This study Toward the aqueous chemistry of element 107, Bh Development of Membrane DeGasser (MDG) and Flow Solvent Extractor (FSE) On-line solvent extraction of Re with the MDG-FSE coupled to the GARIS gas-jet system Measurement of gas-jet transport, dissolution, and solvent extraction times of Re in the MDG-FSE 4
Experimental (1): Production of Re isotopes RIKEN GARIS Rotating nat Gd 2 O 3 target Differential pumping section Elastic scattering beam monitor 23 Na beam ERs ( 174 Re) from RILAC Beam dump D1 Q1 Q2 Irradiation room Gas inlet D2 0 Focal plane ERs 1 2 m 33 Pa Gas-jet transport system Mylar window: 2.5 µm He/KCl 0 100 mm nat Gd 2 O 3 target nat Gd( 23 Na,xn) 174 Re (T 1/2 = 2.4 min) 176 Re (T 1/2 = 5.3 min) Beam: 124.3-MeV 23 Na 7+, 1.6 particle μa Target: 349 µg/cm 2 nat Gd 2 O 3 on 3-µm Ti GARIS Bρ: 1.73 Tm Gas-jet chamber 5
Experimental (1): Solvent extraction of Re isotopes GARIS gas-jet system Gas out H + + [ReO 4 ] + TOA [HReO 4 TOA] org. 174 Re He/KCl aerosols Membrane filter Organic phase () Teflon capillary (i.d. = 0.5 mm) Membrane filter γ-ray spectrometry Mylar window: 2.5 µm Irradiation room Aqueous solution () He: 1.5 L/min Chemistry laboratory Collection on glass fiber filter γ-ray spectrometry Distribution ratio, D = [A] org. /[A] aq. (A: radioactivities) Chemical yield, C.Y. = ([A] org. + [A] aq. ) 100/[A] glass fiber filter D vs. Capillary length D vs. [TOA] phase 0.5 M HNO 3 0.5 M HNO 3 phase 0.01, 0.1 M TOA / toluene 0.005 0.1 M TOA / toluene Capillary length (30), 40, (50), 70, 100 cm 40 cm Extraction equilibrium time, applicable D range 6
MDG and FSE Membrane DeGasser (MDG) Flow Solvent Extractor (FSE) Gas out Teflon capillary (i.d. = 0.5 mm) out in Gas-jet in Ooe et al., J. Radioanal. Nucl. Chem. 303, 1317 (2015). Flow Solvent Extractor (FSE) PTFE Membrane filter AVDAVNTEC No. T300A013A Pore size: 3.0 µm Phase separator Komori et al., RIKEN Accel. Prog. Rep. 49,29 (2016). 7
Experimental (1): Solvent extraction of Re isotopes GARIS gas-jet system Gas out H + + [ReO 4 ] + TOA [HReO 4 TOA] org. 174 Re He/KCl aerosols Membrane filter Organic phase () Teflon capillary (i.d. = 0.5 mm) Membrane filter γ-ray spectrometry Mylar window: 2.5 µm Irradiation room Aqueous solution () He: 1.5 L/min Chemistry laboratory Collection on glass fiber filter γ-ray spectrometry Distribution ratio, D = [A] org. /[A] aq. (A: radioactivities) Chemical yield, C.Y. = ([A] org. + [A] aq. ) 100/[A] glass fiber filter D vs. Capillary length D vs. [TOA] phase 0.5 M HNO 3 0.5 M HNO 3 phase 0.01, 0.1 M TOA / toluene 0.005 0.1 M TOA / toluene Capillary length (30), 40, (50), 70, 100 cm 40 cm Extraction equilibrium time, applicable D range 8
Experimental (2): Measurement of gas-jet transport, dissolution, and extraction times 152 Gd( 23 Na,5n) 170 Re (T 1/2 = 9.2 s) ~ 265 Sg and 266 Bh 170 Re (9.2 s) Irradiation room He/KCl aerosols Membrane filter Gas out Chemistry laboratory Extraction capillary i.d. = 0.5 mm L = 100 cm Mylar window: 3.5 µm He: 1.5 L/min γ-ray spectrometry Phase separator Glass fiber filter (ADVANTEC GB-100R) Radioactivity Beam on 10 s Beam off 110 s Radioactivity Beam on 10 s Beam off 110 s Delay Elapsed time Elapsed time 8
Experimental (2): Measurement of gas-jet transport, dissolution, and extraction times 152 Gd( 23 Na,5n) 170 Re (T 1/2 = 9.2 s) ~ 265 Sg and 266 Bh 170 Re (9.2 s) Irradiation room He/KCl aerosols Membrane filter Gas out Chemistry laboratory Extraction capillary i.d. = 0.5 mm L = 100 cm Mylar window: 3.5 µm Phase separator Radioactivity Beam on 10 s He: 1.5 L/min Beam off 110 s Delay Glass fiber filter (ADVANTEC GB-100R) Time distributions of radioactivity were measured by γ-ray spectrometry. Elapsed time 9
Results and discussion (1): Solvent extraction of Re isotopes Counts / 0.5 kev 10 5 10 4 10 3 10 2 109.1 176 Re 113.0 174 Re 123.2 172 Re 130.2 173 W 148? 181.5 173 Re γ-ray spectrum 184.5 175 Re 190.7 173 Re 196.9 177 Re 240.2 176 Re ( T 1/2 = 5.3 min) 243.4 174 Re (T 1/2 = 2.4 min) 253.9 172 Re RUN: F07-1 Aerosol coll.: 60 s Cooling time: 60 s Meas. time: 60 s 349.5 174 Re, 351.2 176 Re 373.6 173 Re D 1 D vs. Capillary length 10 0.5 M HNO 3 [TOA] = 0.01 M 174 Re MDG-FSE 176 Re MDG-FSE 181 Re Batch ext. 10 1 195? 120 180 240 300 360 Energy / kev 0.1 0 20 40 60 80 100 Capillary length / cm Extraction equilibrium of 174,176 Re is attained with a 30-cm capillary. Time required for solutions to pass through the capillary: ~1.8 s. Average chemical yields of 174,176 Re: ~75% 10
Results and discussion (1): Solvent extraction of Re isotopes D vs. TOA concentration Capillary length (L) = 40 cm 100 0.5 M HNO 3 D vs. Capillary length 100 0.5 M HNO 3 [TOA] = 0.1 M 10 D D 10 1 174 Re MDG-FSE 176 Re MDG-FSE 181 Re Batch ext. 174 Re MDG-FSE 176 Re MDG-FSE 181 Re Batch ext. 0.1 10-3 10-2 10-1 10 0 TOA concentration / M 1 0 20 40 60 80 100 Capillary length / cm D values of 174,176 Re agree well with those of 181 Re in equilibrium at [TOA] 0.01 M. The 40-cm capillary is too short for Re to reach the extraction equilibrium at [TOA] 0.05 M. MDG-FSE is applicable in the wide range of D = 0.3 20 with the 100-cm capillary. 12
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times Net counts per 1 s Net counts per 1 s 300 200 100 Cumulative and differential time distribution of 170 Re Beam on (10 s) GARIS Aerosol Beam on (10 s) collection apparatus ΔT Net counts of 170 Re (305.7 kev) Run 1 (Accumulation and decay of radioactivity) Net counts of 170Re (305.7 kev) Fit with Fit with a "LogNormal lognormal function" Time distribution of 170Re Differential time distribution of 170 Re (arb. unit) Aerosol collection apparatus Net counts per 1 s Net counts per 1 s 200 150 100 50 ΔT GARIS Outlet of the MDG Run The 3 fitted experimental data were deconvoluted with Net counts of 170Re (305.7 kev) a response Fit with "LogNormal function function" Time distribution of 170Re exp( ln(2)*t/9.2) MDG + (5 + 20) cm capillary 0 0 0 10 20 30 40 50 60 70 80 Time since start of beam irradiation [s] Time since start of beam irradiation [s] 0 0 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 Time since start of beam irradiation [s] Time since start of beam irradiation [s] Average transport time (ΔT): time interval from a half of the irradiation time (5 s) to the time that gives 50% of the integral value of the differential time distribution of 170 Re 13
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times GARIS gas-jet system Gas out Chemistry laboratory 170 Re He/KCl aerosols Membrane filter Mylar window Irradiation room He: 1.5 L/min Extraction capillary (EC) i.d. = 0.5 mm L = 100 cm Phase separator (PS) 114 kpa 154 kpa 3.1 s 5.1 s 114 kpa 13.2 s 145 kpa 18.6 s 154 kpa 22.7 s Gas-jet chamber Aerosol collection apparatus Outlet of MDG Outlet of EC Outlet of PS 13
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times GARIS gas-jet system 170 Re He/KCl aerosols Membrane filter Gas out Chemistry laboratory 114 kpa 154 kpa Mylar window Irradiation room He: 1.5 L/min Gas-jet transport 3.1 s 5.1 s Extraction capillary (EC) i.d. = 0.5 mm L = 100 cm Phase separator (PS) 114 kpa 145 kpa 13.2 s 18.6 s 154 kpa 22.7 s Gas-jet chamber Aerosol collection apparatus Outlet of MDG Outlet of EC Outlet of PS 13
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times GARIS gas-jet system 170 Re He/KCl aerosols Membrane filter Gas out Chemistry laboratory 114 kpa 154 kpa 114 kpa 145 kpa Mylar window Irradiation room He: 1.5 L/min Gas-jet transport 3.1 s 5.1 s 13.2 s 18.6 s 10.1 s (Calc. 4.4 s) Dissolution Extraction capillary (EC) i.d. = 0.5 mm L = 100 cm Phase separator (PS) 154 kpa 22.7 s Gas-jet chamber Aerosol collection apparatus Outlet of MDG Outlet of EC Outlet of PS 13
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times GARIS gas-jet system 170 Re He/KCl aerosols Membrane filter Gas out Chemistry laboratory 114 kpa 154 kpa 114 kpa 145 kpa Mylar window Irradiation room He: 1.5 L/min Gas-jet transport 3.1 s 5.1 s 13.2 s 18.6 s 10.1 s (Calc. 4.4 s) Dissolution Extraction capillary (EC) i.d. = 0.5 mm L = 100 cm Extraction 6.3 s (Calc. 5.9 s) Phase separator (PS) 154 kpa 22.7 s Gas-jet chamber Aerosol collection apparatus Outlet of MDG Outlet of EC Outlet of PS 13
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times GARIS gas-jet system 170 Re He/KCl aerosols Membrane filter Gas out Chemistry laboratory 114 kpa 154 kpa 114 kpa 145 kpa Mylar window Irradiation room He: 1.5 L/min Gas-jet transport 3.1 s 5.1 s 13.2 s 18.6 s 10.1 s (Calc. 4.4 s) Dissolution Extraction capillary (EC) i.d. = 0.5 mm L = 100 cm Extraction 6.3 s (Calc. 5.9 s) Phase separator (PS) Phase separation 3.6 s (Calc. 3.1 s) 154 kpa 22.7 s Gas-jet chamber Aerosol collection apparatus Outlet of MDG Outlet of EC Outlet of PS 13
Summary We have been developing a new rapid solvent extraction apparatus consisting of MDG and FSE coupled to the GARIS gas-jet system for the future aqueous chemistry of Sg and Bh. On-line solvent extraction of Re was successfully performed using MDG-FSE coupled to the GARIS gas-jet system. Rapid equilibrium time: ~2 6 s (30 100 cm capirrary) Wide applicable D range of D = 0.3 20 High chemical yield: ~75% Gas-jet transport, dissolution, and solvent extraction times of Re in the developed apparatus were investigated. Gas-jet transport time: 5.1 s at 154 kpa Overall time: Dissolution time in the MDG: 10.1 s ~25 s Solvent extraction time in the FSE: 6.3 s (100-cm extraction capillary) + 3.6 s (phase separator) 14
Future outlook We will modify the MDG to shorten the dissolution time. A flow liquid scintillation detection system will be developed. Interesting chemistry systems for Sg and Bh are under study using radiotracers of their homologues. Hydrolysis and fluoride complex formation of Sg(VI) Refs: A. Kronenberg et al., Radiochimica Acta 92, 395 (2004). X. H. Liang et al., J. Radioanal. Nucl. Chem. 292, 917 (2012). Formation of anionic species of Bh(VII), [BhO 4 ] Redox studies of Bh(VII) Bh(IV) Ref: M. Schädel, D. Shaughnessy, The Chemistry of Superheavy Elements, Second Edition, Springer, Heidelberg, 2014. 15
21
Feasibility of aqueous chemistry of Sg and Bh Continuous solvent extraction and LS detection (Present apparatus) Nuclide T 1/2 [s] σ [pb] Target [μg/cm 2 ] Beam [pμa] Cool. T. [s] Chem. Y. [%] Detec. eff.* [%] Event rate for α-α [1/d] 265 Sg a 8.5 180 300 4 10 50 100 2.8 265 Sg b 14.4 200 300 4 10 50 100 4.9 266 Bh 10.0 57 300 4 10 50 100 1.0 Batch-wise chemical separation (e.g. ARCA and AIDA) Nuclide T 1/2 [s] σ [pb] Target [μg/cm 2 ] Beam [pμa] Coll. T. [s] Cool. T. [s] Chem. Y. [%] Detec.* eff. [%] Event rate for α-α [1/d] 265 Sg a 8.5 180 300 4 30 30 50 9 0.02 265 Sg b 14.4 200 300 4 30 30 50 9 0.1 266 Bh 10.0 57 300 4 30 30 50 9 0.01 * Efficiencies for α-α correlations. 22
Experimental (2): Measurement of gas-jet transport, dissolution, and extraction times 152 Gd( 23 Na,5n) 170 Re (T 1/2 = 9.2 s) ~ 265 Sg and 266 Bh 170 Re (9.2 s) Irradiation room He/KCl aerosols Membrane filter Gas out Chemistry laboratory Extraction capillary i.d. = 0.5 mm L = 100 cm Mylar window: 3.5 µm Phase separator Radioactivity Beam on 10 s He: 1.5 L/min Beam off 110 s Delay Glass fiber filter (ADVANTEC GB-100R) Time distributions of radioactivity were measured by γ-ray spectrometry. Elapsed time 9
Convolution and deconvolution A convolution of two functions, f and g is written as f g. ff gg tt = ff ττ gg tt ττ ddττ ff : (Differential) time distribution of radioactivity gg : Decay of radioactivity, exp( ln(2)*t/9.2) Algorithms for deconvolution Deconvolution is performed based on the convolution theorem FFT ff gg = FFT(ff)FFT(gg) ff = IFFT FFT ff gg FFT(gg) Cumulative time distributions of radioactivity of 170 Re (T 1/2 = 9.2 s) Net counts per 1 s Net counts per 1 s 300 200 100 Beam irradiation (10 s) Net counts of 170 Re (305.7 kev) Run 1 (Accumulation and decay of radioactivity) Net counts of 170Re (305.7 kev) Fit with Fit with a "LogNormal lognormal function" Time distribution of 170Re Differential time distribution of 170 Re (arb. unit) Aerosol collection apparatus where FFT and IFFT denote fast Fourier transform and its inverse, respectively. 0 0 0 10 20 30 40 50 60 70 80 Time since start of beam irradiation [s] Time since start of beam irradiation [s]
Convolution and deconvolution A convolution of two functions, f and g is written as f g. ff gg tt = ff ττ gg tt ττ ddττ Cumulative time distributions of radioactivity of 170 Re (T 1/2 = 9.2 s) f: (Differential) time distribution of radioactivity g: Decay of radioactivity, exp( ln(2)*t/9.2) To derive the differential time distribution of radioactivity (f), we deconvoluted the fitted experimental data with the response function g. Net counts per 1 s Net counts per 1 s 300 200 100 Beam on (10 s) ΔT Net counts of 170 Re (305.7 kev) Run 1 (Accumulation and decay of radioactivity) Net counts of 170Re (305.7 kev) Fit with Fit with a "LogNormal lognormal function" Time distribution of 170Re Differential time distribution of 170 Re (arb. unit) Aerosol collection apparatus 0 0 0 10 20 30 40 50 60 70 80 Time since start of beam irradiation [s] Time since start of beam irradiation [s]
Extractant: tri-n-octylamine (TOA) Tri-n-octylamine (TOA) An liquid-anion exchanger 26
Appendix 100 1 M HNO 3 100 0.5 M HNO 3 10Slope (Tc) = 1.2 10 Slope = 1.4 D 1 Slope (Re) = 1.4 95m Tc (FSE) 183 Re (FSE) 95m Tc (batch) 183 Re (batch) D 1 174 Re MDG-FSE 176 Re MDG-FSE 181 Re Batch ext. 0.1 10-3 10-2 10-1 10 0 TOA concentration / M 0.1 10-3 10-2 10-1 10 0 TOA concentration / M 27
100 0.5 M HNO 3 10 Slope = 1.4 D 1 174 Re MDG-FSE 176 Re MDG-FSE 181 Re Batch ext. 0.1 10-3 10-2 10-1 10 0 TOA concentration / M 28
Introduction: Aqueous chemistry of SHEs Aqueous chemistry of SHEs (Z 104) Aqueous chemistry of Rf, Db, and Sg has been performed using a batch-wise column chromatography apparatus (ARCA) with Si detectors. Nuclide Half-life (s) Production rate* (atoms/h) 261 Rf a 68 420 262 Db 34 70 265 Sg a,b 8.5/14.4 12 266 Bh 10.0 1.7 * 248 Cm target thickness: 300 μg/cm 2 ; Beam intensity: 2 pμa Pioneering cation-exchange studies of Sg in HNO 3 /HF and HNO 3 Schädel et al., Radiochim. Acta 77, 149 (1997).; Radiochim. Acta 83, 163 (1998). Decay loss during aerosol collection and α-source preparation (~30 s) Low detection efficiency: eff.(α) = ~30% eff.(α-α) = ~9%; eff.(α-α-α) = ~3% A huge amount of background radioactivities of by-products Requirements for the aqueous chemistry of Sg and Bh Continuous, rapid, and efficient aqueous chemistry apparatus Low-background condition for α/sf detection 29
Experimental (1): RIKEN RI Beam Factory D2(10 o ) Q2 Q1 D1(45 o ) GARIS RILAC Chem. Lab. 30
RIKEN GARIS gas-jet system RIKEN GARIS Gas-jet transport system Differential pumping section Evaporation Beam from RILAC Residues (ERs) Beam dump Gas inlet Focal plane Mylar window 50 kpa ERs Rotating target 33 Pa Elastic scattering beam monitor D1 Q1 Q2 Haba et al., Chem. Lett. 38, 426 (2009). 0 D2 1 2 m He/KCl 0 100 mm By-products are removed almost completely. Production and decay studies of 265 Sg a,b and 266 Bh were successfully performed: 248 Cm( 22 Ne,5n) 265 Sg a,b Haba et al., Phys. Rev. C 85, 024611 (2012). 248 Cm( 23 Na,5n) 266 Bh Haba et al., APSORC 17, A-049 Pre-separated 265 Sg a,b and 266 Bh are ready for the chemistry experiments at GARIS. 31
Results and discussion (1): Production of Re isotopes Counts / 0.5 kev 10 5 10 4 10 3 10 2 10 1 Nuclide 109.1 176 Re 113.0 174 Re 123.2 172 Re 130.2 173 W 148? 181.5 173 Re 184.5 175 Re 190.7 173 Re 195? 196.9 177 Re 240.2 176 Re 243.4 174 Re 120 180 240 300 360 Bρ [Tm] γ-ray spectrum 253.9 172 Re Energy / kev Yield@Chem. Lab. [kbq/pμa min ] RUN: F07-1 Aerosol coll.: 60 s Cooling time: 60 s Meas. time: 60 s 349.5 174 Re, 351.2 176 Re 373.6 173 Re Gas-jet eff. [%] 174 Re 1.74±0.01 55±2 70±3 176 Re 1.76±0.01 16±1 76±2 Ref. Firestone and Shirley, Table of Isotopes, 8th ed., Wiley, New York, 1996. Counts per second Counts per second Decay curves of 174,176 Re 10 2 10 1 10 0 0 2 4 6 8 10 12 10 2 174 Re E γ = 243.4 kev T 1/2 = 2.3 ± 0.1 min Ref. 2.40 ± 0.04 min 176 Re E γ = 240.2 kev T 1/2 = 5.4 ± 0.2 min Ref. 5.3 ± 0.3 min 10 1 0 2 4 6 8 10 12 Elapsed time [min] 32
Results and discussion (1): Solvent extraction of Re isotopes D vs. Capillary length 10 0.5 M HNO 3 [TOA] = 0.01 M 174 Re MDG-FSE 176 Re MDG-FSE 181 Re Batch ext. Capillary length [cm] Chemical yield Chamber pressure [kpa] Chemical yield [%] 174 Re 176 Re D 1 0.1 0 20 40 60 80 100 Capillary length / cm 100 160 86 ± 5 97 ± 6 70 150 81 ± 7 91 ± 7 50 76 ± 13 85 ± 17 40 142 59 ± 21 65 ± 25 30 139 52 ± 13 56 ± 11 Extraction equilibrium of 174,176 Re is attained with the 30-cm capillary. Time required for solutions to pass through the capillary: ~1.8 s. Applicable for 10-s 266 Bh Chemical yields of 174,176 Re increase with increasing the capillary length and the pressure of the gas-jet chamber. 33
Experimental (1): Production of Re isotopes RIKEN GARIS Rotating nat Gd 2 O 3 target Elastic scattering beam monitor Differential pumping section 23 Na beam ERs ( 174 Re) from RILAC Beam dump D1 Q1 Q2 nat Gd( 23 Na,xn) 174 Re (T 1/2 = 2.4 min) Beam: 130.6-MeV 23 Na 7+, 0.33 pμa Target: 340 µg/cm 2 nat Gd 2 O 3 on 2-µm Ti GARIS Bρ: 1.58 1.94 Tm Irradiation room Gas inlet D2 0 Focal plane ERs 1 2 m 33 Pa Gas-jet transport system Mylar window: 0.7 µm 78 kpa He/KCl 0 100 mm 10 m He: 5 L/min Chem. Lab. Glass fiber filter (ADVANTEC GB-100R) γ-ray spectrometry nat Gd 2 O 3 target Gas-jet chamber 20-μm Al catcher γ-ray spectrometry 34
Experimental (1): Solvent extraction of Re isotopes GARIS gas-jet system Gas out H + + [ReO 4 ] + TOA [HReO 4 TOA] org. 174 Re He/KCl aerosols Membrane filter Organic phase () Teflon capillary (i.d. = 0.5 mm) Membrane filter γ-ray spectrometry Mylar window: 2.5 µm Irradiation room Aqueous solution () He: 1.5 L/min Chemistry laboratory Collection on glass fiber filter γ-ray spectrometry Distribution ratio, D = [A] org. /[A] aq. (A: radioactivities) Chemical yield, C.Y. = ([A] org. + [A] aq. ) 100/[A] glass fiber filter D vs. Capillary length D vs. [TOA] phase 0.5 M HNO 3 0.5 M HNO 3 phase 0.01, 0.1 M TOA / toluene 0.005 0.1 M TOA / toluene Capillary length (30), 40, (50), 70, 100 cm 40 cm Extraction equilibrium time, applicable D range 35
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times GARIS gas-jet system 170 Re He/KCl aerosols Membrane filter Gas out Chemistry laboratory Mylar window Irradiation room Extraction capillary (EC) i.d. = 0.5 mm L = 100 cm Phase separator (PS) He: 1.5 L/min 114 kpa 154 kpa 114 kpa 145 kpa 3.1 s 5.1 s 13.2 s 18.6 s 10.1 s (Calc. 4.4 s) 6.3 s (Calc. 5.9 s) 3.6 s (Calc. 3.1 s) 154 kpa 22.7 s Gas-jet chamber Aerosol collection apparatus Outlet of MDG Outlet of EC Outlet of PS 15
Results and discussion (2): Measurement of gas-jet transport, dissolution, and extraction times Net counts per 1 s Net counts per 1 s 300 200 100 Cumulative and differential time distribution of 170 Re Beam on (10 s) GARIS Aerosol Beam on (10 s) collection apparatus ΔT Net counts of 170 Re (305.7 kev) Run 1 (Accumulation and decay of radioactivity) Net counts of 170Re (305.7 kev) Fit with Fit with a "LogNormal lognormal function" Time distribution of 170Re Differential time distribution of 170 Re (arb. unit) Aerosol collection apparatus Net counts per 1 s Net counts per 1 s 200 150 100 50 ΔT GARIS Outlet of the MDG Run The 3 fitted experimental data were deconvoluted with Net counts of 170Re (305.7 kev) a response Fit with "LogNormal function function" Time distribution of 170Re exp( ln(2)*t/9.2) MDG + (5 + 20) cm capillary 0 0 0 10 20 30 40 50 60 70 80 Time since start of beam irradiation [s] Time since start of beam irradiation [s] 0 0 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 Time since start of beam irradiation [s] Time since start of beam irradiation [s] Average transport time (ΔT): time interval from a half of the irradiation time (5 s) to the time that gives 50% of the integral value of the differential time distribution of 170 Re 37
Continuous and rapid solvent extraction apparatus Development of a continuous and rapid solvent extraction apparatus coupled to the GARIS gas-jet system for aqueous chemistry of Sg and Bh GARIS gas-jet system He/KCl aerosols 265 Sg a,b, 266 Bh Membrane DeGasser (MDG) Gas out Flow Solvent Extractor (FSE) Membrane filter Organic phase () Membrane filter Photomultiplier tube Mylar window Irradiation room Aqueous solution () Chemistry laboratory Teflon capillary (i.d. = 0.5 mm) Phase separator Liquid scintillator Liquid scintillation α/sf detectors Continuous dissolution, solvent extraction, and radiation detection Minimization of decay loss of 265 Sg a,b and 266 Bh Efficient α/sf detection with LS: eff.(α-α/sf) = ~100% 38