Preparation of gas-chemistry of Dubnium at IMP Z. Qin, J.S. Guo, X.L. Wu, H.J.Ding, W.X.Huang, Z.G. Gan, Institute of Modern Physics, Chinese Academy of Sciences,
content 1. Study of Transactinides by rotating wheel. 2. Preparation of Gas-chemistry for SHE.
? 241 Am( 22 Ne, 4n) 259 Db ? Partial chart of nuclide 243 Am( 26 Mg, 4n) 265 Bh
Energy constant: K ~ 70 (E k ~6-7MeV/A) Intensity: ~ 3×10 13 pps (C-Ne) ~ 5×10 12 pps (Mg-Ar) SFC: Sector Focusing Cyclotron, HIRFL
22 Ne 241 Am Fusion 263 Db* 259 Db Hot fusion reaction
0.8 µA 118 MeV 22 Ne 5+ Improved Rotating Wheel system Transportation time≈ 0.3 s efficiency ≈ 50% He-NaCl-jet 241 Am(910 g/cm 2 ) + Al(1.7mg/cm 2 ) NaCl 259 Db Recoil chamber A-1 A-2 B-1 C-1 A-3 B-2 D-1 B-3 D-3 C-2 D-2 C-3
259 Db -spectrum of the reaction 22 Ne Am 255 Lr
Decay-curve of 258,259 Db and their daughter 254,255 Lr 258 Db E = 9.08, 9.17, 9.30 MeV T 1/2 = 4.3±1.1s 254 Lr E = 8.46 MeV T 1/2 = 13.4±4.2s, 258 Db T 1/2 = 4.3±1.4s
241 Am( 22 Ne,4~5n) 258,259 Db 258 Db 4.4 s 4n 5n Db 0.5 s 254 Lr 13 s 255 Lr 21 s Z.G. Gan, Z.Qin, H.M. Fan, et al., Eur. Phys. J., A10(2001)21
Rotating Multi-detector Arrays( ROMA)
-spectrum of the reaction 26 Mg Am at energy of 168 MeV
Paren t 1 / keV t 1 / ms Daught er 2 / keV t 2 / ms Grand- daught er 3 / keV t 3 / ms 265 Bh Db Bh Db Lr Bh Db Lr Bh Db Bh Db Bh Db Bh Db Bh Db Bh Db Bh Db Bh Db Bh Db - correlation events observed from 243 Am( 26 Mg,4~5n) 264,265 Bh
243 Am( 26 Mg,4~5n) 264,265 Bh Z.G. Gan, J.S.Guo, X.L.Wu, Z.Qin, et al., Eur. Phys. J., A20(2004) Bh 1 s 4n 5n Bh 0.9 s 260 Db 1.5 s 261 Db 1.8 s 257 Lr 0.65 s Q = 9.38 MeV RMF calculation Q = 9.41 MeV
22 Ne+ 249 Bk 271 Bh* Berkeley, PRL, 85 (2000)2697 Beam: 300 particle nA Energy: 117, 123 MeV Time: 62h Dose: 4×10 17 One Events of 266 Bh: E =9.29 MeV life-time:0.87s
Preliminary!! Rg 270 Mt 266 Bh CN MeV (PSD) 344 μs mm MeV (PSD+SSD) ms mm MeV (PSD+SSD) ms mm 9.08 MeV (PSD) s mm MeV TOF ns mm 1 st chain July 23, :55 (JST) Morita et al.:JPSJ 73, 2593 (2004). α α α α 262 Db MeV(PSD) 40.9 s mm Rg 270 Mt 266 Bh CN MeV (PSD) 4.93 ms mm =11.31 MeV (PSD+SSD) 34.3 ms mm 2.32 MeV (escape) 1.63 s mm 9.77 MeV (PSD) 1.31 s mm MeV TOF ns mm 2 nd chain April 2, :18 (JST) Decay chains of α α α α 262 Db MeV(PSD) s mm SF σ = fb 209 Bi + 70 Zn → n
HIVAP calculation
Beam energy: 162 MeV 26 Mg 8+ Beam energy: 162 MeV 26 Mg 8+ Beam intensity: 2 e A Target: 1.2 mg/cm Am Transport efficiency: 50% Detector efficiency: 30% Stepping time: Mother Mode:4s, Daughter Mode:60s Irradiation time: 200h Experiment condition
-spectrum of the reaction 26 Mg Am at energy of 162 MeV
- correlation events observed from 243 Am( 26 Mg,3n) 266 Bh Event No.E 1 /MeV t 1 /s E 2 /MeV t 2 /s E 1 /MeV t 3 /s - correlation energy window: MeV Daughter life-time window: 20-60s
243 Am( 26 Mg,3n) 266 Bh 266 Bh ~0.9 s 262 Db 34 s 258 Lr 4 s
LBL RIKEN 1 st RIKEN 2 nd This work E (MeV) Lifetime (s) Decay properties of 266 Bh
Comparison of Q value from the experiment with Macro-micro Model
Production of Dubnium: 243 Am( 20 Ne, 4~5n) 258, 259 Db 258 Db: T 1/2 = 4.4s, E = 9.17, 9.08, 9.01 MeV Carrier gas: He/KBr Reaction gas: HBr Gas-chemistry: OLGA-III Detection: Rotating wheel system
On-line gas chemistry Apparatus OLGA-III
Summary 1. Two new isotopes of 259 Db and 265 Bh were synthesized 2.The known isotope of 266 Bh was studied, and E close to the RIKEN first chain. 3. Db gas chemistry is under going.
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