Results of 226Ra 48Ca Experiment Yu'Tsyganov, Yu'Oganessian, V'Utyonkov, Yu'Lobanov, F'Abdullin, I'S

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Results of 226Ra48Ca ExperimentYu.Tsyganov
Yu.Oganessian V.Utyonkov Yu.Lobanov
F.Abdullin I.Shirokovsky A.Polyakov
V.Subbotin A.Sukhov R.Sagaidak A.Voinov and
JINR (Dubna) LLNL (Livermore) TUM (Muenchen)
INS Vinca (Belgrade) collaboration
Yu.Tsyganov 07 Apr. IOP-2009 Birmingham UK

• Content
• Introduction
• Synthesis of 269-271Hs by TUM group
  (briefly properties)
• 2) Experiment at U-400 cyclotron using DGFRS
• a) The Dubna Gas Filled Recoil Separator
  detection module experiment motivation...
• b) Parameters of experiment
• c) Results and discussion
• 3) Summary
• Nearest future experiments predictions of
  cross sections

Target wheel mounting
Sci. leader
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270
271
New isotopes
3n/4n ratio
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Experimental setup of TUM group (discovery 270Hs
)
Transport time 3 s
Transport time 1 s
No T1/2 value for 270Hs can be measured because
of missing of EVR signal !
by Dr. Alexandr Yakushev (TUM )
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The Dubna Gas Filled recoil Separator (JINRLLNL
since 2001)
226Ra target design ( six sectors form-
RaO) Foil 1.5 mcm Ti.
GSI RIKEN
.

.
.

Experiment 226Ra48Ca270Hs4n
DGFRS 2008

• Why...
• to check decay properties 270271Hs discovered by
  TUM group
• to measure cross sections of 34 n reaction
  channels ( a) by itself b) as a parameter for
  any extrapolations/corrections to Z117-120 )

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DGFRS Detection module
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position windows corresponding to two position
resolutions (2.35 standard deviations
confidence level (c.l.) 0.98).
E9.020.08 MeV T1/27.64.92.2 s the
half-life of the daughter spontaneously
fissioning isotope is 0.280.90.08 s in
agreement with TUM group results (E8.880.05 MeV
for 270Hs and TSF0.360.250.10 s for 266Sg).
233.2 2.8 projectile energy Excitation energy
40.0 2.2 MeV Target 0.23 and 0.36
mg/cm2 (two runs) Beam dose 4.11018 Cross
section 8.3 6.73.3 pb
ltEEVRgt13.00.77 MeV Calculated 13.2 MeV
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Background level
Time intervals between particles and all
preceding ER-like events observed within two ER-
or ER-SF position resolutions (2.35 standard
deviations) are shown. Time intervals for the
nearest ER events assigned to implantation of
270Hs in detectors are shown by arrows. Dash
line shows distribution dN/d(lg10 t) for
T1/27.6 s. Dash-dot line shows linear fit for
random ER-like events.
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But..3n! (they give max channel)
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Summary
Yu.Tsyganov IOP-2009
1) Cross section for the 226Ra48Ca270Hs4n
reaction was measured as about 8.3 pb ( beam
dose 31018 part. ) Decay properties of 270Hs
measured by TUM group are confirmed (in
principle) 2) Both 3n and 5n channel decays
were not detected for the beam doses 6.21018 (
4.2 pb if T1/24s) and 2.31018 ( 5.0 pb )
respectively. 3) Calculations by Adamyan at al.
(PRC 69 (2004) ) do not reproduce in principle
the maximum reaction channel number (3n except
for 4n measured in our experiment) ---------------
--------------------------------------------------
------------------------------------- 4) Cross
section values for the future 243Am 50Ti and
249Cf 50Ti reactions may have of greater values
than ones predicted by W.Greiner V.Zagrebaev
calculations
V.Zagrebaev and W.Greiner calculations