Transcript Slide 1

STATUS REPORT ON THE “MASHA” SET-UP
A.M.Rodin, A.V.Belozerov, S.N.Dmitriev, Yu.Ts.Oganessian,
R.N.Sagaidak, V.S.Salamatin, S.V.Stepantsov, D.V.Vanin
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
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Introduction
Status of the mass-spectrometer MASHA
From ISOL technique to gas catcher
Future
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010

Introduction
Detectors
MAss
Separator of
Heavy
Atoms
Ion source
D1
Q1 Q2
D2
S2
Q3
General ion-optical parameters
Range of energy variation, kV
15-40
Range of Br variation, Tm
0.08-0.5
Mass acceptance, %
+/-2.8
Angular acceptance, mrad
+/-14
Diameter the ion source exit hole, mm
5.0
Horizontal magnification at F1/F2
0.39/0.68
Mass dispersion at F1/F2, mm/%
1.5/39.0
Linear mass resolution at F1 75
Mass resolution at F2
1150
S1
D3a
D3b
The proposed setup is a combination
of the so-called ISOL method of
synthesis and separation of
radioactive nuclei with the classical
method of mass analysis, allowing
mass identification of the
synthesized nuclides in the wide
mass range.
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
Introduction
Chemistry of the element 112
250
Po Pb
experimantal data
least square fit:
95% c.i.
Tl
Bi
-Hads(Au), kJ/mol
200
150
Hg
100
At
-52+20-4 kJ/mol50
Xe
Rn
-Hads (Au) = (1.08±0.05)*Hsubl+(10.3±6.4), kJ/mol
Kr
0
0
50
100
150
200
250
Hsubl, kJ/mol
Hsubl=39+23-10 kJ/mol (68%c.i.)
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
Status of the mass-spectrometer MASHA
Heater
Hot catcher
(graphite)
Target
112, 114
TO ECR
Heavy ion
beam
Separating foil
First experiments:
Mass identification of 112 и 114 elements synthesized at the reactions
242Pu(48Ca,3n)287114(0.5 s, a) –> 283112(4 s, a 9.95 MeV)
244Pu(48Ca,3-4n)289114 (2.7 s, a 9.82 MeV) –> 283112(4 s, a 9.95 MeV)
Mass identification of 113 elements synthesized at the reaction
243Am(48Ca,3n)288115 (80 ms, a 10.5 MeV ) ->284113(0.5 s, a 10.0 MeV,
(analog of Tallium)
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
Status of the mass-spectrometer MASHA
Mass-spectrometer MASHA
at the beam line of the cyclotron U-400M
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New beam line with low energy of the U-400M was built
Mass-spectrometer mounted at the new beam line
Hot catcher is ready
Focal plane detector system is ready
Start of test and first experiments – April of 2010
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
Status of the mass-spectrometer MASHA
0.15
84
Kr
A
0.10
2.42 strips
R=1400
0.05
86
83
82
0
0
20
40
60
80
100
120
140
160
180
Strip number
Mass spectrum of Kr isotopes:
Total efficiency – 47%
Mass resolution - 1400
Mass measurement accuracy – 1.3x10-5
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
From ISOL technique to gas catcher
Main parameters of gas catcher
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Operating gas – He purity <0,1 ppm.
Operating pressure into gas cell – 100
mbar.
Extraction time – 10 ms.
Efficiency 10-40%.
Beam emittance ~1.0 p.mm.mrad
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
From ISOL technique to gas catcher
Ideal gas stopper
• Short extraction times. Extraction times of 10 ms or less would be ideal.
• Big enough efficiency. Not less than 20%.
• Handling of high beam intensities. The facility should provide secondary
beam intensities of up to 109 s-1.
• Applicability to all fragment beams.
• Universality.
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
From ISOL technique to gas catcher
General ion-optical parameters of MASHA
Parameter
Range of energy variation, kV
ECR
ion source
Gas
catcher
15-40
15-40
0.08-0.5
0.08-0.5
Mass acceptance, %
2.8
2.8
Angular spread, mrad
14
5
Diameter the ion source exit hole, mm
5.0
1.0
Horizontal magnification at F1/F2
0.39/0.68
0.24/0.90
Vertical magnification at F1/F2
2.40/3.13
8.75/1.25
Mass dispersion at F1/F2, mm/%
1.5/39.0
1.5/39.0
75
420
1150
5700
Range of Bρ variation, Tm
Linear mass resolution at F1
Mass resolution at F2
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
From ISOL technique to gas catcher
~107 c-1 of 48Ca (6 MeV/n)
Observation of beam rate-dependent efficiencies as a function of the
ionization rate in gas stopping systems at MSU, RIKEN,
GSI/SHIPTRAP, LISOL/Leuven, and ANL.
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
From ISOL technique to gas catcher
Gas-filled recoil separator
0.200 m
Magnet:
Bρmax = 2.7 Tm
B0max = 6.0 T
Banding angle = 82.4o
Rcentre ray = 45.2 cm
Centre ray length = 65 cm
Pole gap, 2h = 10 cm
Beam horizontal working region = ±10 cm
Entrance (exit) pole tilt angle =
30o(14.7o)
30
o
1 4 ,7
0.500 m
o
Separator characteristics:
Target – magnet distance = 1.0 m
Magnet – catcher entrance distance = 1.0 m
Solid angle = 10.0 msr
ΘX = ± 4.6o, ΘY = ± 2.3o
∆P/P (full) = 4.5%
Focal plane dispersion = 2.7 cm/%Bρ
Gas – H2 at the pressure 1-5 mbar
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
From ISOL technique to gas catcher
Simulation for SHE
Reaction: 48Ca + 238U →286112* →283112 + 3n
Target:
backing foil Ti(0.75 mg/cm2) + UF4 (0.4 mg/cm2)
Beam:
E0 (48Ca) = 234 MeV (4.88 MeV/n)
diameter on target = 10 mm
εX = εY = 30π mm mrad (r.m.s)
∆E/E0 = ± 0.5% (r.m.s)
Total transmission – 65%
4000
4000
3000
3000
2000
2000
1000
1000
0
0
-2
-1 .5
-1
-0 .5
0
qX (Y ) (
0 .5
1
1 .5
2
214
216
48
C a ), d e g
218
E(
48
220
222
224
C a ), M e V
2000
6000
1600
4000
1200
800
2000
400
0
0
0
2
4
6
8
10
q(
12
283
14
16
11 2 ) , d e g
18
20
22
24
24
26
28
30
E(
32
34
283
11 2 ) , M e V
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
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From ISOL technique to gas catcher
Experimental facility for very heavy nuclei research
G as-filled
reco il separato r
D etectors
M ass-spectro m eter
Q
Ta rget
Ion beam
G as
catcher
S
D
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
Future
Methodic development
• Gas catcher and gas-filled recoil separator
• New design of the silicon detectors DSD with 0.1 mm strips
• Germanium detectors for Z identification
• New electronics and data acquisition
• Start detector based on electron emission from silicon
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010
Future
Experimental research
• Mass identification of heaviest nuclides
• Mass measurements of heavy nuclides with accuracy up to 10-7
• Decay spectroscopy of neutron deficit and neutron rich nuclides with A
and Z identification
• Synthesis and decay research of new neutron rich nuclides
• Collinear laser spectroscopy at the wide area of the nuclide chard
PAC for Nuclear Physics, 31st meeting, 25-25 January 2010