Post on 29-Aug-2019
RIKEN Nishina CenterHiromitsu Haba
for the SHE synthesis collaboration at GARIS
Present Status and Perspectives of SHE Syntheses at RIKEN GARIS
1. Production and decay studies of RIs for SHE chemistry248Cm(23Na,5n)266Bh
2. Future plans of SHE syntheses at RIKEN
CONTENTS
Breakthroughs in SHE chemistryCoupling SHE chemistry to a recoil separator
• Chemical experiments under low background condition• Stable and high gas‐jet transport yields• New chemical reactions
• Chemical experiments under low background condition• Stable and high gas‐jet transport yields• New chemical reactions
1. Production and decay studies of RIs for SHE chemistry
Production and decay studies of SHE RIs for chemical studies
• 248Cm(18O,5n)261Rfa,b [Chem. Lett. 38, 426 (2009); PRC 83, 034602 (2011)]• 248Cm(19F,5n)262Db [PRC 89, 024618 (2014)]• 248Cm(22Ne,5n)265Sga,b [PRC 85, 024611 (2012)]→ Sg(CO)6 chemistry• 248Cm(23Na,5n)266Bh [This work]
• 248Cm(18O,5n)261Rfa,b [Chem. Lett. 38, 426 (2009); PRC 83, 034602 (2011)]• 248Cm(19F,5n)262Db [PRC 89, 024618 (2014)]• 248Cm(22Ne,5n)265Sga,b [PRC 85, 024611 (2012)]→ Sg(CO)6 chemistry• 248Cm(23Na,5n)266Bh [This work]
• 169Tm(40Ar,3n)206Fr; 208Pb(40Ar,3n)245Fm [JNRS 8, 55 (2007); EPJD 45, 81 (2007)]• 238U(22Ne,5n)255No [JNRS 9, 27 (2008)]• 169Tm(40Ar,3n)206Fr; 208Pb(40Ar,3n)245Fm [JNRS 8, 55 (2007); EPJD 45, 81 (2007)]• 238U(22Ne,5n)255No [JNRS 9, 27 (2008)]
Development of a gas‐jet transport system coupled to GARIS
Focal plane
1 2 m0
D2(10o)Q2Q1D1(45o)
Differential pumping section
Beam from RILAC
Gas inlet
Elastic scattering beam monitor
ERs
Mylar window
He/KCl
0 100 mm
33 Pa
50 kPa
Experimental setupRIKEN GARIS Gas‐jet transport system
Rotating target
10 m
15 pairs of Si PIN photodiodesMylar foil
Chemistry laboratoryMANON for α/SF spectrometry
0 100 mm
Si PIN photodiode
ERs
33 Pa
Focal plane Si detector
Exhaust
Evaporation Residues (ERs)
Nuclide 266Bh (T1/2 = 1.20 s1)) 267Bh (T1/2 = 13.7 s1))Reaction 248Cm(23Na,5n) 248Cm(23Na,4n)
Cross section (pb) ~50 (5n + 4n)? 2)
Beam energy, Elab. (MeV) 131Beam intensity (pμA) 3
248Cm2O3 thickness (μg/cm2) 290; 250Magnetic rigidity (Tm) 2.12
GARIS He (Pa) 33RTC Mylar window (μm) 0.7Honeycomb grid (%) 78Gas‐jet He (kPa) 80
Chamber depth (mm) 20He flow rate (L/min) 5.0KCl generator (oC) 620
Step interval of MANON (s) 5.0; 8.5; 15.01) Wilk et al., PRL 85, 2697 (2000).; Eichler et al., Nature 407, 63 (2000).; Morita et al., JSPS 81, 103210 (2012).; Qin et al.,Nucl. Phys. Rev. 23, 400 (2006).2) Morira et al., JPSJ 78, 064201 (2009).
Experimental conditions
0
20
40
60
80
100
120
7 8 9 10 11 12
Cou
nts
/ 40
keV
energy / MeV
7.68
7 21
4 Po
(B.G
.: 22
2 Rn)
8.56
5, 8
.595
, 8.6
21, 8
.654
258 L
r?8.
45 25
9 Lr,
8.46
262 D
b?
7.15
0, 7
.192
254 F
m
8.78
5 21
2 Po
(B.G
.: 22
0 Rn)
8.68
262 D
b?
8.82
-9.7
7 26
6 Bh?
8.85
267 B
h?
8.35
5 26
3 Db?
8.73
267 B
h?
Beam energy: 131 MeV248Cm: 264 μg/cm2
Beam dose: 8.4×1018GARIS: Bρ = 2.12 TmChamber press.: 80 kPaHe: 5.0 L/minKCl: 620 oCColl. step: 5.0; 15.0 s15 up detectors
Beam energy: 131 MeV248Cm: 264 μg/cm2
Beam dose: 8.4×1018GARIS: Bρ = 2.12 TmChamber press.: 80 kPaHe: 5.0 L/minKCl: 620 oCColl. step: 5.0; 15.0 s15 up detectors
Table of Isotopes, 8th ed. (1996).Wilk et al., PRL 85, 2697 (2000).Eichler et al., Nature 407, 63 (2000).Qin et al., Nucl. Phys. Rev. 23, 400 (2006).Morita et al., JSPS 78, 064201 (2009). Morita et al., JSPS 81, 103210 (2012).Haba et al., PRC 89, 024618 (2014).
α‐particle spectrum
263Db27 s8.36
259Lr6.3 s8.45
266Bh1.20 s
8.82–9.77
267Bh13.7 s
8.73, 8.85
258Lr3.5 s
8.595, 8.621,8.565, 8.654
262Db34 s
8.46, 8.68
8.0
8.2
8.4
8.6
8.8
9.0
9.2
9.4
8.0 8.2 8.4 8.6 8.8 9.0 9.2 9.4
Dau
ghte
r e
nerg
y (M
eV)
Parent energy (MeV)
150
200
250
SF e
nerg
y (M
eV)Search for α‐α/SF correlations
Eα1 = 8.00–10.00 MeVEα2; α3 = 8.00–8.73 MeVESF ≥ 50 MeV; Si top & bottom coin.ΔT ≤ 340 s [= 10 T1/2(262Db)]
Observed Randomα‐α‐α 4 < 0.01α‐α 5 < 0.82α‐SF 7 < 0.06
No α‐α/SF correlation on 263Db
262Db258Lr
263Db259Lr
263Db 262Db 267Bh 266Bh
No. of the observed correlations
263Db27 s8.36
259Lr6.3 s8.45
266Bh1.20 s
8.82–9.77
267Bh13.7 s
8.73, 8.85
258Lr3.5 s
8.595, 8.621,8.565, 8.654
262Db34 s
8.46, 8.68
Excitation function calculated by HIVAPReisdorf and Schädel, ZPA 343, 47 (1992).Nishio et al., PRL 93, 162701 (2004).Nishio et al., PRC 82, 024611 (2010).
10-2
10-1
100
101
This work (5n)Nagame 2002 (5n)Tsukada 2009 (5n)Dressler 1999 (5n)Trubert 2002 (5n)This work (4n)This work (6n)
35 40 45 50 55 60
90 95 100 105 110 115
Cro
ss s
ectio
n (n
b)
4n6n
5n
Eex (MeV)
ELab (MeV)
101
102
103
100 105 110 115 120 125 130 135 140
This workDGFRS 1994OLGA 1998PSI-Tape 2000PSI-Tape 1998HITGAS 2001
Cro
ss s
ectio
n (p
b)
Lab-frame energy ELab (MeV)
5n
4n
6n3n
0
4
1 1
2
6
12
29
Haba et al., PRC 83, 034602 (2011).Murakami et al., PRC 88, 024618 (2013).
10-1
100
101
102
Murakami et al. (2013)Haba et al. (2011)
80 85 90 95 100 105 110
Cro
ss s
ectio
n (n
b)
4n 6n
5n
Lab-frame energy ELab (MeV)
3n
Haba et al., PRC 85, 024611 (2012).Haba et al., PRC 89, 024618 (2014).
248Cm(18O,xn)266–xRf248Cm(19F,xn)267–xDb
248Cm(22Ne,xn)270–xSg
100
101
102
110 115 120 125 130 135 140 145 150
Cro
ss s
ectio
n (p
b)
Lab-frame energy ELab (MeV)
266Bh(5n)
267Bh(4n)
265Bh(6n)
248Cm(23Na,xn)271–xBhThis work
• For 248Cm(23Na,xn)271–xBh, σ(5n) is 60 pb, and σ(4n) is more than one order of magnitude smaller than σ(5n).
→ Most of the observed events in this work can be assigned to 266Bh.
Decay properties of 266Bh• Eα of 266Bh spread widely in Eα = 8.62–9.40 MeV.
• T1/2 = 10.7+4.2–2.4 s in this work is longer than those of 266Bh in the literatures.
0
2
4
10-2 10-1 100 101 102 103
Cou
nts
Time (s)
T1/2 = 10.7 s
0
1
2
3
4
5
8.0 8.5 9.0 9.5 10
correlated to decay 262Dbcorrelated to SF decay of 262Db
Cou
nts
/ 25
keV
energy (MeV)
NuclideThis work Refs. [1–4]
N T1/2 [s] N T1/2 [s]266Bh 12 10.7+4.2–2.4 8 1.20+0.66–0.31267Bh 11 13.7+5.9–3.2
[1] 249Bk(22Ne,5;4n)266,267Bh (N = 1, 5): Wilk et al., PRL 85, 2697 (2000).[2] 249Bk(22Ne,4n)267Bh (N = 6): Eichler et al., Nature 407, 63 (2000).[3] 243Am(26Mg,3n)266Bh (N = 4): Qin et al., Nucl. Phys. Rev. 23, 400 (2006). [4] 209Bi(70Zn,n)278113 → 266Bh (N = 3): Morita et al., JPSJ 81, 103201 (2012).
• The longer half‐life of 266Bh is good for Bh chemistry in the future.
• Existence of an isomeric state in 266Bh?→ Further investigation of 267Bh at a
lower beam energy
Assumptions• T1/2(266Bh) = 10.7 s• SF branch of 266Bh: bSF = 0%• GARIS transmission: 15%• Gas‐jet transport efficiency: 50%• Gas‐jet transport time: 2.7 s
Excitation function for 248Cm(23Na,5n)266Bh
ReactionCross section
Reaction*Cross sections*
at 131 MeV at 117/123 MeV248Cm(23Na,5n)266Bh 55±16 pb 249Bk(22Ne,5n)266Bh ‐/25–250 pb
249Bk(22Ne,4n)267Bh 58+33–15/96+55–25 pb*Wilk et al., PRL 85, 2697 (2000).
100
101
102
110 115 120 125 130 135 140 145 150
Cro
ss s
ectio
n (p
b)
Lab-frame energy ELab (MeV)
5n
4n6n
248Cm(23Na,xn)271–xBh
• The 248Cm(23Na,5n)266Bh cross section is comparable to the 249Bk(22Ne,5;4n)266,267Bh.
• HIVAP reproduces the 248Cm(23Na,5n)266Bh cross section.
100
101
102
103
104
105
106
107
100 105 110
Cross sectio
n (pb)
Atomic number
261Rfa,b RIKEN [3]
265Sga,b RIKEN [5]266Bh RIKEN [6]
262Db RIKEN [4]
269Hs GSI [7]
258Lr Berkeley [2]
255,256No Berkeley [1]
References[1] Sikkeland et al., PL 172, 1232 (1968).[2] Eskola et al., PRC 4, 632 (1971).
[3] Haba et al., PRC 83, 034602 (2011); [4] Haba et al., PRC 89, 024618 (2014). [5] Haba et al., PRC 85, 024611 (2012). [6] This work
[7] Dvorak et al., PRL 100, 132503 (2008).
Cross section systematics for the 248Cm(X,5n) reactions
2. Future plans of SHE syntheses at RIKEN
• 248Cm(23Na,xn)271–xBh (in progress)• Aqueous chemistry of Sg and Bh by solvent extraction with LS Development of a rapid solvent extraction apparatus coupled to GARIS→ TASCA15 contribu on by Y. Komori
• Gas chemistry of organometallic compounds of SHEs→ Assessing the thermal stability of Sg(CO)6 (R. Eichler and Ch. E. Düllmann)
• 248Cm(23Na,xn)271–xBh (in progress)• Aqueous chemistry of Sg and Bh by solvent extraction with LS Development of a rapid solvent extraction apparatus coupled to GARIS→ TASCA15 contribu on by Y. Komori
• Gas chemistry of organometallic compounds of SHEs→ Assessing the thermal stability of Sg(CO)6 (R. Eichler and Ch. E. Düllmann)
• 248Cm(50Ti,xn)298–x118 (Feb.–Mar., 2016)☑ 50Ti‐MIVOC with Cp*50TiMe3 from Univ. Strasbourg
→ Accelera on test in Jun., 2015: 0.5 pμA on target; 0.22 mg/h□ 9 mg of 248Cm shipped to RIKEN from ORNL (Dec., 2015)
→ Prepara on of 248Cm rotating target (500‐μg/cm2; φ100 mm)□ GARIS II commissioning (Oct. 21–28, 2015 and Jan. 25–Feb. 15, 2016)
→ 238U(48Ca,xn)286–xCn and 248Cm(48Ca,xn)296–xLv
• 248Cm(50Ti,xn)298–x118 (Feb.–Mar., 2016)☑ 50Ti‐MIVOC with Cp*50TiMe3 from Univ. Strasbourg
→ Accelera on test in Jun., 2015: 0.5 pμA on target; 0.22 mg/h□ 9 mg of 248Cm shipped to RIKEN from ORNL (Dec., 2015)
→ Prepara on of 248Cm rotating target (500‐μg/cm2; φ100 mm)□ GARIS II commissioning (Oct. 21–28, 2015 and Jan. 25–Feb. 15, 2016)
→ 238U(48Ca,xn)286–xCn and 248Cm(48Ca,xn)296–xLv
Chemistry using preseparated 261Rfa, 262Db, 265Sga,b, and 266Bh
Syntheses of the heaviest SHEs
Collaborators for the GARIS gas‐jet experimentNishina Center for Accelerator‐Based Science, RIKENM. Huang, D. Kaji, J. Kanaya, Y. Komori, K. Morimoto, K. Morita, M. Murakami, M. Takeyama, K. Tanaka, T. Tanaka, Y. Wakabayashi, S. Yamaki, and A. Yoneda
Osaka Univ.Y. Kasamatsu, N. Kondo, K. Nakamura, A. Shinohara, and T. Yokokita
Tohoku Univ.H. Kikunaga
Niigata Univ.R. Aono, H. Kudo, K. Ooe, and S. Tsuto
Advanced Science Research Center, JAEAK. Nishio, A. Toyoshima, and K. Tsukada
IMPF. L. Fan, Z. Qin, and Y. Wang