Precision experiments of stored exotic nuclei

Precision experiments of stored exotic nuclei
mass & lifetime measurements at the storage rings
Taka Yamaguchi (Saitama, Japan)
For FRS-ESR/ILIMA collaboration,
For Rare-RI Ring collaboration
1. Highlights of the ESR experiments
 Time-resolved Schottky mass spectrometry (SMS)
 Isochronous mass spectrometry (IMS)
2. Future facilities
• ILIMA collaboration (FAIR)
•
•
Upgrade of present activities at ESR
Rare-RI Ring collaboration (RIBF)

2010年9月26日日曜日
Concept, principle, R&D
1
FRS-ESR Facility at GSI
All elements: H-U
Energy: up to 1GeV/u
Monoisotopic fragment beams
stored in the ESR
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Schottky Mass Spectrometry,
Isochronous Mass Spectrometry
SMS
Stochastic
+
Electron
cooling
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IMS
Isochronous
optics
3
Frequency Spectrum, an example
Yu.A.
Litvinov
Y. Litvinov
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4
Sensitivity to single ions
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High-accuracy Mass Measurements
Mass Evaluation of Close-lying Frequency Peaks
δm/m=4.3x10-8
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Mass Surface measured with the SMS
Masses of more than 1000
Nuclides were measured
Mass accuracy: 1.5 ·10-7
Mass resolving power: 2 ·106
Results: 320 new masses
In addition more than
300 improved mass values
Yu.A. Litvinov et al., Nucl. Phys. A756 (2005) 3.
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Recent Highlights with the SMS
•Proton-neutron interaction strength around N=126
•L. Chen et al., PRL102(2009)122503.
•New isomers
•Excitation energies, lifetimes
•B. Sun et al., PLB688(2010)294.
•M.W. Reed et al., PRL accepted.
•New isotopes discovered at ESR
•Mass simultaneously measured
•L. Chen et al. PLB691(2010)234.
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Time-resolved Schottky Mass Spectrometry
Electron cooling
SMS
Schottky
Pick-ups
amplification
summation
FFT
f0 ~ 2 MHz
0
Continuous digitizing and storage of raw data
Time after injection / s
Stored ion beam
0
β + -decay
nuclear e - -capture
150
300
450
β + -decay
600
8.0
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8.1
8.2
8.3
8.4
8.5
153.9
154.0
154.1
154.2
Frequency / kHz
9
Nuclear Decays observed in the Ring
Yu.A. Litvinov
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Lifetime Measurements via SMS
Exotic decay modes of highly-charged ions
Bound-state beta decay of 207Tl81+
T. Ohtsubo at al., PRL95(2005)052501.
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Recent Highlights with the SMS
38
N. Winckler et al. / Physics Letters B 679 (2009) 36–40
Fully ionized
•Electron capture decays of HCI
Enhancement of EC rates of hydrogen-like ions
•Y. Litvinov et al., PRL99(2007)262501.
•N. Winckler et al., PLB679(2009)36.
•Non-exponential EC decays
166
•Y. Litvinov et al., PLB664(2008)162.
Yu.A. Litvinov et al. / Physics Letters B 664 (2008) 162–168
H-like
He-like
Fig. 5. A zoom to the first 33 s after injection of the 142 Pm data presented in Fig. 4. The solid line represents the exponential decay fit according to Eq. (1). The dashed line
142
60+
Fig. 1.
(Color online.)
evolution
hydrogen-like
shows the fit according to Eq. (2). Both fits were done until 33 s after
injection
and areTime
marked
with of
anintensities
asterisk inofTable
2. The insetPm
showsparent
the FFT spectrum obtained
142
ions and
the fully-ionized
Nd60+ daughter
ions to
stored
in the ESR. TheFFT
intensity
from these data. A clear FFT peak is observed at about 0.14 Hz (laboratory
frame).
Its reduced resolution
as compared
the corresponding
in Fig. 3 is explained by the
is
plotted
on
a
logarithmic
scale.
The
upper,
middle
and
lower
panels
correspond
Fig. 2. (Color online.) An example of a measured decay curve of fully-ionized
smaller number of points used.
142
to three Schottky frequency spectra averaged over about 2.6 seconds and which
Pm61+ ions is shown in the upper panel. Decay curves of H-like and He-like
142
are taken at the beginning, at the middle and at the end of a measurement cycle,
Pm together with the corresponding growth curves of fully-ionized and H-like
2
142
respectively.
Nd ions(oneare illustrated in the middle and in the lower panel, respectively. Each
Table 2
χ /DoF-values from Table 2 on the 99% confidence level
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Isochronous Mass Spectrometry
-> 40GS (TDS6154C)
TOF detector
MCP
C foil
Secondary
electrons
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MCP
13
Pulses of Stored Ions
raw data
Look for repeating peaks
J. Stadlmann
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Time-of-Flight Spectrum
Fragments from fission of 238U
Δ(m/q)/(m/q) ~ 13%
Identification by m/q ratio
B. Sun, R. Knoebel, S. Nakajima
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Isochronicity - improvement -
ΔT/T [10-5]
Revolution Time
Bρ-tagging method
ΔBρ/Bρ [10-3]
H. Geissel
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Experiment 2006
Goal: to measure the masses of
n-rich fission products at the
r-process path
Bρ-tagging was applied
Primary beam: 238U
Intensity: ~ 3·109/spill
ESIS : 411MeV/u
Target : 1g/cm2 9Be
B. Sun et al. Nucl. Phys. A 812 (2008) 1
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FAIR
- Future Facility -
SIS 100/300
Future facility
SIS 18
ESR
GSI today
Super
-FRS
RESR
from FAIR web site
CR
NESR
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Mass & Lifetime Measurements at CR/NESR
ILIMA collaboration
Bρ-tagging
R&D
IMS
SMS
•Ion optics
•Resonant Schottky probe
•TOF Detectors
•Multiple pickup
•DAQ, analysis softwares
•Decay particle detectors
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ILIMA collaboration at FAIR
K. Takahashi (Bruxelles)
E. Badura, K. Beckert, F. Bosch, D. Boutin, A. Dolinski, B. Franzke,
H. Geissel, F. Herfurth, J. Hoffmann, H.-J. Kluge, C. Kozhuharov, S.A. Litvinov,
G. Muenzenberg, I. Nesmiyan, F. Nickel, F. Nolden, W. Otto, W. Quint, C. Scheidenberger
M. Steck, Th. Stoehlker, S. Typel, H. Weick, M. Winkler (GSI)
M. Hausmann, M. Matos, H. Schatz (MSU)
T. Faestermann, P. Kienle, L. Maier, P. Ring, D. Vretenar (Muenchen)
D.M. Seliverstov, G.K. Vorobjev (St. Petersburg)
L. Chen, Z. Di, T. Dickel, A. Fettouhi, R.K. Knoebel, M. Petrick, W.R. Plass (Giessen)
Z. Podolyak, P.M. Walker (Surrey)
stable nuclei
Th. Buervenich (Frankfurt)
R. Mao, Z. Sun, G. Xiao (Lanzhou)
nuclides with known masses
G.Audi et al., Nucl. Phys. A729 (2003) 3
D. Madland, P. Moeller, D. Vieira (Los Alamos)
to be measured with SUPER-FRS-CR-RESR-NESR
K.-L. Kratz, B. Pfeiffer (Mainz)
Conceptual Design Report, GSI 2001
K. Blaum (Max-Planck)
observed nuclei
82
D. Cullen (Manchester)
T. Ohtsubo (Niigata)
G.
Audi,
D. Lunney (Orsay)
r-process
path
T. Yamaguchi (Saitama)
126
G.A. Lalazissis (Thessaloniki)
Z. Patyk (Warsaw)
50
82
28
50
20
8
28
Isomeric Beams, Lifetimes and Masses
Spokesperson: P.M. Walker
20
8
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Measure the masses in the r-process
Rare-RI Ring project at RIBF
T. Fujinawa, N. Fukunishi, A. Goto, H. Sakurai, M. Wakasugi, Y. Yamaguchi, Y. Yano
RIKEN Nishina Center
I. Arai, T. Moriguchi, D. Nagae, A. Ozawa, H. Suzuki
Univ. of Tsukuba
82
T. Suzuki, T. Yamaguchi,
Saitama Univ.
proton drip-line
T. Kikuchi
Nagaoka Univ.of Tech
A/Z=3 line
50
126
neutron drip-line
28
82
20
50
8
2
16
2
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28
Z
8
N
r-process path
stable nuclei
unstable nuclei
(with known masses)
AME2003
21
Conceptual Design
Individual injection method
Trigger signal
B
SRC
PID
100MeV/u
A
F3
Kicker
Isochronous
Storage
Ring TOF ~ 1ms
BigRIPS
PID
C
Long injection beam line
Accuracy of requirement
β measurement
TOF measurement δT /T < 10-6
β measurement δβ / β < 10-4
-6
Isochronous magnetic field δB0 / B0 < 10
€
€
€2010年9月26日日曜日
Δm/m ~ 10-6
22
Layout of Rare RI Ring
Mass measurement =
BigRIPS + SHARAQ line + Storage Ring
RI Beam Factory
Rare RI Ring
BigRIPS
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R&D ongoing
•Optics calculations
•Injection beam line
•Injection/ejection scheme
•Storage Ring
oHigher-order/realistic calculations
TARNII-D 24
TARNII-Q 20
KEK-PS-Q 23
•Kicker, Septum
•Improved controller: response time ~450ns
•Specifications
oTest of model kicker
•TOF counters
•Test of µm-thick plastic scintillator
•Test of hybrid photo detector
•Test of MCP detector
•High-precision NMR probe
•Precision ~ 10-7
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CSR - Cooler Storage Ring at Lanzhou -
Major parameters of CSRe
Max. Energy: 400MeV/u (U90+)
Intensity: 109
Bρ(max): 8.40 Tm
First IMS at CSRe :
2009 Sep.-Oct.
59Zn, 61Ga, 63Ge, 65As, 67Se, 71Kr
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Concluding Remarks
-
Storage Ring Mass Spectrometry at ESR is ongoing.
- Large areas of unknown mass surface
- Exotic decay modes of highly-charged ions
-
The future international collaboration ILIMA at FAIR is promising
for the continuation and upgrade of the current ESR activities.
-
Rare-RI Ring project will work in a complementary style.
-
The storage ring in China is a candidate to extend our activities.
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