Study of the heavy elements at IMP

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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,
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content
1. Study of Transactinides by rotating
wheel. 2. Preparation of Gas-chemistry for SHE.
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Partial chart of nuclide
?
?
243Am( 26Mg , 4n) 265Bh
241Am( 22Ne , 4n) 259Db
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SFC Sector Focusing Cyclotron, HIRFL
Energy constant K 70 (Ek6-7MeV/A) Intensity
31013 pps (C-Ne) 51012 pps
(Mg-Ar)
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Hot fusion reaction
Fusion
263Db
22Ne
241Am
259Db
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0.8 µA 118 MeV 22Ne5
B-3
A-1
D-3
C-1
B-1
C-3
241Am(910?g/cm2) Al(1.7mg/cm2)
A-2
D-1
C-2
A-3
B-2
D-2
Improved Rotating Wheel system
NaCl
Transportation time 0.3 s efficiency 50
He-NaCl-jet
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255Lr
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Decay-curve of 258,259Db and their daughter
254,255Lr
258Db E? 9.08, 9.17, 9.30 MeV T1/2 4.31.1s
254Lr E? 8.46 MeV T1/2 13.44.2s, 258Db T1/2
4.31.4s
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Rotating Multi-detector Arrays( ROMA)
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?-spectrum of the reaction 26Mg 243Am at energy
of 168 MeV
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? - ? correlation events observed from
243Am(26Mg,45n)264,265Bh
Parent ?1 / keV t1 / ms Daughter ?2 / keV t2 / ms Grand-daughter ?3 / keV t3 / ms
265Bh 9268 1736 261Db 9006 4860
265Bh 9300 1015 261Db 8924 224 257Lr 8905 4639
265Bh 9219 574 261Db 8921 1898 257Lr 8887 1405
265Bh 9274 193 261Db 8918 5834
265Bh 9222 1140 261Db 8942 436
265Bh 9179 1933 261Db 8902 1523
265Bh 9245 2547 261Db 8869 1608
265Bh 9199 1334 261Db 8927 3480
264Bh 9440 555 260Db 8988 2686
264Bh 9501 2770 260Db 9085 1378
264Bh 9524 1203 260Db 9003 259
264Bh 9481 2321 260Db 9098 975
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243Am(26Mg,45n)264,265Bh
Z.G. Gan, J.S.Guo, X.L.Wu, Z.Qin, et al., Eur.
Phys. J., A20(2004)385
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Beam 300 particle nA Energy 117, 123 MeV Time
62h Dose 41017
One Events of 266Bh E?9.29 MeV life-time0.87s
Berkeley, PRL, 85 (2000)2697
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209Bi 70Zn ? 278113 n
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HIVAP calculation
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Experiment condition

• Beam energy 162 MeV 26Mg8
• Beam intensity 2 e?A
• Target 1.2 mg/cm2 243Am
• Transport efficiency 50
• Detector efficiency 30
• Stepping time
• Mother Mode4s, Daughter Mode60s
• Irradiation time 200h

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?-spectrum of the reaction 26Mg 243Am at energy
of 162 MeV
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? - ? correlation events observed from
243Am(26Mg,3n)266Bh
Event No. E?1/MeV ?t1/s E?2/MeV ?t2/s E?1/MeV ?t3/s
1 8.989 1.13 8.459 33.62
2 9.128 0.88 8.676 33.84
3 9.071 0.79 8.604 34.14
4 8.959 0.51 8.542 29.23 8.641 5.07

• - ? correlation energy window 8.5-10 MeV
• Daughter life-time window 20-60s

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243Am(26Mg,3n)266Bh
8.60 8.62 8.57 8.65
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Decay properties of 266Bh
LBL RIKEN 1st RIKEN 2nd This work
E?(MeV) 9.29 9.08 9.77 9.04 Lifetime (s) 0.87 2.469 1.31 0.9
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Comparison of Q? value from the experiment with
Macro-micro Model
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Production of Dubnium 243Am( 20Ne, 45n)258,
259Db 258Db T1/2 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
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On-line gas chemistry Apparatus OLGA-III
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Summary

• 1. Two new isotopes of 259Db and 265Bh were
  synthesized
• The known isotope of 266Bh was studied, and E?
  close
• to the RIKEN first chain.
• 3. Db gas chemistry is under going.

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Thank you for attention