Mass Measurements with MRTOF at RIKEN RIBF · Kimura et al.,IJMS 430 (2018) 134 Y. Ito et al.,to be...
Transcript of Mass Measurements with MRTOF at RIKEN RIBF · Kimura et al.,IJMS 430 (2018) 134 Y. Ito et al.,to be...
Mass Measurements with MRTOF at RIKEN RIBF
Michiharu Wada for the SHE-Mass CollaborationKEK, Wako Nuclear Science Center
NUSTAR Meeting 2018
Mass measurement of short-lived nuclei Summary of measurement @GARIS-II Mc and Nh measurement preparation Plan at the end of ZeroDegree
Why Atomic Mass?p
p p p
n n n
n n nAtom is ≈1% lighter than constituents: Mass Deficits
Mass Deficit = Binding Energy B
Most fundamental nuclear propertyDefines Stability, Decay mode, Structure
Finger Print: Unique value for a nucleus
Derivation of mass:Sn (n-separation energy)
Atomic massΣ constituents
Key values for NucleoSynthesis
G-Wave γ-flash
r-process nova?
optical
Astro Physicist:“We saw the moment of Au Pt synthesis in n-star merger!”
H. Koura
Masses to be measured
Mass Known(δm/m<10-6): 2300Experimentally Synthesized:≈3300
Synthesized but Mass unknown:≈1000
note: many known masses were measured indirectly
Ni
Sn
Ca
Pb
H HHeHe
Li LiBeB B
C CN N
O O OFNeNeNe
NaMgMgMg
AlSi Si Si
PS S S
ClS
ArClArK
Ar
CaKCaCaCa
ScCa
Ti Ti Ti Ti TiVCr Cr Cr
FeMnFe Fe Fe
NiCoNi Ni Ni
CuNi
ZnCuZn Zn Zn
GaGe
GaGeGeGe
SeAs
Ge
SeSeSe
KrBr
Se
KrBrKr Kr Kr
SrRb
Kr
Sr Sr SrYZr Zr Zr
MoNb
Zr
MoMoMo
Ru
MoMo
RuRuRuRuRu
PdRh
Ru
Pd PdPd
CdAg
Pd
CdAg
Pd
CdCdCd
SnIn
Cd
SnSn
Cd
Sn SnSnSnSn
TeSb
Sn
TeSb
Sn
Te Te Te
XeIXe XeXe
Ba
XeXe
BaCs
Xe
Ba BaBa
Ce
BaBa
CeLaCePrNdNd
Sm
NdNd Nd
SmEu
SmEu
Sm
GdGdGd
Dy
GdGd
DyTb
Gd
DyDy Dy
Er
DyDy
ErHoEr Er Er
YbTm
Er
YbYbYbYb YbLu
Yb
Hf Hf Hf Hf Hf
WTaW
ReW
OsOsOsOsIr
Os
PtIrPt Pt Pt
HgAu
Pt
HgHgHgHgHgTl
HgTlPb PbPb
Bi
U
decay, reaction (660)
mass spectrometry
+4
0
-4
log(T1/2)
log (T1/2)
T1/2: 10 ms - 100 ms most abundant
0
50
100
150
200
250
300
350
-8-6-4-202468
c_unk1ppm2016_life.m
cf. AME2016
Mass Measurements of Short-lived NucleiQ-value (decay or
reaction)
In-flight spectrometer
Storage RingPenning Trap
MRTOF (multi-reflection TOF)
Ultra FastLow Precision
FastLow Precision
Isochronous
Electron Cooling
Very SlowHigh Precision
SlowUltra precision
FastHigh Precision
New method
UniversalAmbiguity from levels
TOFI, SPEG ..
GSI ESRIMP CSRe
RIKEN RI-RingISOLDE, JYFL...
RIKEN, Giessen, ISOLDE ..
indirect direct
(1)
(2)
(3)
(4)
(5)
MRTOF Mass SpectrographPo
tent
ial (
V)Open entrance to inject
Close entrance before coming back
go back and forth for ≈200 times
Open exit at pre-defined timing
Detect ions’ ToF
Ion Trap Ion MirrorTOF
detector
(Multi Reflection Time of Flight…)
Ion Mirror
k=k+α
k=k-α
A=205@223lapsA=204@223laps
205Fr+204Fr+ 205Rn+204Rn+
205At+ 100,000 cycles in 3000s
garbages @ different laps
total 7000 events
>90% are no ions
garbage ions can be discriminated by different number of laps
0
1
2
3
4
-40 -20 0 20 40
Cou
nts
/ 2 n
s
ToF - 5652584.8 (ns)
0
1
2
3
4
-40 -20 0 20 40
n = 145 lapsToF(250Md2+) = 5 652 584.8(2.1) ns
ToF − 5 652 584.8 (ns)
250Md++ measurement ≈ 1 event /1000 s
Mass determined with δm/m = 6x10-7
P. Schury et al, PRC 95(2017)011305(R)
≈0.3 ppm precisionA=204
A=205
A=204
A=205
27 μs
27 μs
Y. Ito et al, PRL 120 (2018)0102501
Typical Mass Measurement Results
TOF ( ns )6318500 6319000 6319500 6320000 6320500
Coun
ts /
6.4
ns b
in
1
10
210
310
225 laps65Cu
65Zn
65Ga ( 6.8 kCnts )
65Ge64ZnH
TOF = 6319028.062(77) ns
R = 1.000038095(38)
R = 1.00007063(20)R = 1.00008911(21)
R = 1.00001123(12)
FWHM = 24.9(1) ns
65Cu(stable)
65Ga(RI)
S. Kimura et al, IJMS 430, 134-142 (2018)
δm/m = 3.5x10-8
IrPt
IrPt Pt Pt
HgAu
Pt
HgHgHgHgHgTl
HgTlPb PbPb
Bi
U
PoAtRnFrRaAc
RaAcThPa
UNpPu
EsFmMdNo
130120 140 150
80
90
100
N
Z
AME2016 (incl. indirect)MRTOF (RIKEN-KEK)
Masses Measured in 2016 summer - 2017 spring> 80 masses were measured in total 4 weeks beam time6 first masses in trans-uranium elements (Es, Md isotopes)> 30 first direct mass measurementsknown masses agree in 1σ with Penning Trap data, while a few discrepancy in old indirect measurementsshortest T1/2 = 10 ms, with precision 2x10-7
Y. Ito to PRL 120, 102501 (2018)
P. Schury et al, in preparation
M. Rosenbusch et al, PRC 97, 064306 (2018)
P. Schury et al, PRC95(2017)011305R
Y. Ito et al, in preparation
Ge,BrA≈65
S. Kimura et al, IJMS 430, 134-142 (2018)
Half Life [s]
1 ppm
0.1 ppm
0.01 ppm
10 ppmIn-flight
Penning Traps
Isochronous storage ring
Cooled ions in storage ring blank zone
Typical Mass Measurements before MRTOFShorter half-life, lower precision
No devices for T1/2≈10 ms, δm/m≈0.1 ppm[a] Y. Bai et al., AIP Conf. Proc. 455 (1998)90.
[b] F. Sarazin et al., Phys. Rev. Lett. 84 (2000)5062.[c] R. Knöbel et al., EP. J.A. 52 (2016)138, Chen et al, NPA882(2012)71[d] Yu.A. Litvinov et al., Nucl. Phys. A756(2005)3.[e] http://research.jyu.fi/igisol/JYFLTRAP_masses/[f] https://isoltrap.web.cern.ch/isoltrap/database/isodb.asp[g] H.S. Xu et al IJMS349(2013)162 and others
Half Life [s]
1 ppm
0.1 ppm
0.01 ppm
10 ppmIn-flight
Penning Traps
Isochronous storage ring
[a] Y. Bai et al., AIP Conf. Proc. 455 (1998)90.[b] F. Sarazin et al., Phys. Rev. Lett. 84 (2000)5062.[c] R. Knöbel et al., EP. J.A. 52 (2016)138, Chen et al, NPA882(2012)71[d] Yu.A. Litvinov et al., Nucl. Phys. A756(2005)3.[e] http://research.jyu.fi/igisol/JYFLTRAP_masses/[f] https://isoltrap.web.cern.ch/isoltrap/database/isodb.asp[g] H.S. Xu et al IJMS349(2013)162 and others
MRTOF ISOLDE
65Ga: δm/m=3.5x10-8still agree with Penning trap
219Ra220Ra
219Ra (T1/2=10ms) δm/m=3x10-7
MRTOF plays a role in Mass Measurements
Kimura et al.,IJMS 430 (2018) 134
Y. Ito et al.,to be submitted
Cooled ions in storage ring
MRTOF RIKEN-KEK
GARIS-II
Beam
Target
Cryogenic RF carpet Gas Cell
1st Ion TrapBeam Stopper
2nd Ion Trap
MRTOF Mass Spectrograph2nd Ion Trap
Reaction Products
Ion Mirror (Inject)
Ion Mirror (exit)
Detector
RI ions
Ref Ions
Beam Transport(5m)
SHE-Mass-I @ RIKEN RILAC
Cryogenic gas cell
RF-Carpet(traveling wave)
Recoil Ions
(Central part)
DC cylinder RF Six-pole beam guideLinear RFQ ion trap
Flat RFQ ion trap
α-β Detector (retractable)
Window(0.5μm)
Exit hole(φ0.7mm)
CoCentric Electrodes (pitch:0.32mm)
1st Ion Trap Setup
Bunched Ion Beam
Md, Es…
SHE-Mass-I @ RILAC
Thermalize
Trap
reTrap
1.6 keV bunched beam
ε: 30-40%
ε: ≈20%
εtotal: 1-2%
Thermalize
Trap
Side View Top View
εtotal: >10% anticipated
SHE-Mass-II @E6
4.8m
Bottleneck!
New GARIS-II
Gas Cell
MRTOF
from 2017 Winter
SHE-Mass-II @E6 RIBFLarge free areaGasCell+Trap+MRTOF all in one
Movable behind SHE exp.
Gas Cell
Ion Trap MRTOF
GARIS-II@E6
α
α
α
α
α
spontanous fission
α
α
α
α
α
α102No
104Rf105Db
106Sg107Bh
108Hs109Mt110Ds
111Rg112Cn
113Nh114Fl115Mc
116Lv117Ts118Og
140
278
274
270
266
262
258
254
288
284
280
276
272
268
110
120
103Lr
100 100Fm101Md
99Es150 160 170
Cold Fusion SHN(Pb, Bi + Stable Ion)
(actinide + 48Ca)Hot Fusion SHNDirect Mass (Our Work)
Indirect Mass(Our Work)Direct Mass(GSI)Indirect Mass(GSI)Discovered Nuclides
Proton(Atomic) Number Z
neutron number N
252251250249
254
251
246
278
(Mass Number A)
253 254
257 258
261 262
266
α
α
α
α
α
α
α
Masses to be measured
Place a first bridge to the Island
Japanese Nihonium
Russian Nihonium
Masses of Super Heavy Nuclides1. pin down masses of hot-fusion “island”2. confirm A and Z of hot-fusion SHE
Candidates in first Hot Fusion SHE Mass Measurement
243Am(48Ca, 3n)288Mc→284Nh→280Rg0.5 mg/cm2 2 pμA 8.5 pb 4 /day@GARIS
0.1 0.2 0.3 0.4 0.5
Time (s)
0.2
0.4
0.6
0.8
1.0
Fraction
0.1 0.2 0.3 0.4 0.5
Time (s)
0.2
0.4
0.6
0.8
1.0
Fraction
243Am(48Ca, 4n)287Mc→283Nh→279Rg
288Mc 287Mc
284Nh
280Rg
283Nh279Rg
εtotal= 10%10 events/month !
248Cm(14N, 4n)258Lrother interesting mass measurements
mass anchor for 278Nh
244Pu(48Ca, xn)292-xFl→288-xCn anchor for even hot fusion SHE
BigRIPS200 MeV/u
150 cm He 200 mbar
30 cm He 100 mbar
30 cm He 1 mbar
GARIS5 MeV/u
KISS30 keV Pin Hole
Ion Traps
MRTOF
SAMURAIZero-Degree Mass Ring
SHARAQ
SCRIT(Universal SLOW RI-beam facility)
New Facility
Existing Facility
RIBF Accelerator BuildingRIBF Accelerator Building
RIBF Experiment BuildingRIBF Experiment Building
fRCfRCFixed frequency ring cyclotronFixed frequency ring cyclotron))
SRCSRC((Superconducting ring cyclotronSuperconducting ring cyclotron))
IRCIRC((Intermediate ring cyclotronIntermediate ring cyclotron))
BigRIPSBigRIPS(Projectile Fragment Separator)(Projectile Fragment Separator)
SLOWRI
RIPS
prototype SLOWRI
GARIS
KISS BigRIPS +SLOWRI
Parallel Measurements @ 3 facilities of RIKEN RIBF
1. Thermalize in He gas2. Extraction by RF-carpet3. Trap in Ion-Traps4. Mass measurements with
MRTOF
@345, 400 MeV/u238U 50 pnA (3x1011 pps)
48Ca 500 pnA (3x1012 pps)
R
6
0
3.
6
10m
187435
818
SLOWRI
5 MRTOF @ BigRIPS of RIBF
OEDORF Carpet Gas Cell(既存設備) MRTOF-MS
Bunching Trap
PALIS-MTOF
SLOWRI-MTOF
Utilize garbage ions at slits
Cocktail beam of BigRIPS
WNSC-HPSP
With pure RI, T1/2, Mass, Pn
KISS2-MTOF
Multi-nucleon transfer products with
10 MeV/u RI-beam
RI beam
ZeroDegree-MTOF
@ Beam dump, 2nd 3rd reaction
products, with free
ZeroDegree
I.C.
TKE BRIKEN1m shift
Gas Cell (3rd prototype SLOWRI)
mini-MTOF
TRAP MTOF (option)
retractable on rails
(degrader)
ZD-MRTOF @ F11 as 3rd Prototype SLOWRI
F11I.C.
TKE Gas Cell
Trap
@F11 Symbiotic Experiment will be run
* Interaction σ exp. * In-beam γ exp.
e.g.
after their measurements,all garbage goes to F11
mass measurement can use them without extra charge
Case study:In-beam exp for 79Ni region40 pnA U beamA week of run1% our total efficiency
What is expected?
0 5 10 15 20 25
1
10
210
310
410
TOF-all
TOF - 4186.72 us
A=81 (n=190)80 (191)79 (192)
78 (193)
77 (194)
82 (188)83 (187)
84 (186)
85 (185)
7.6 7.8 8 8.2 8.4 8.6 8.8 9 9.2 9.4
1
10
210
310
TOF A=78
TOF - 4186.72 us
78Ni (193)
78Cu (193)
84Ge (186)
Expected TOF Spectrum (simulation)
12.6 12.8 13 13.2 13.4 13.6 13.8 14
1
10
210
310
TOF A=79
79Zn (192) 79Cu (192)
79Ni (192)
17 17.2 17.4 17.6 17.8 18 18.2 18.4 18.6 18.8 19
1
10
210
310
410
TOF A=80
84Ga (186)
80Zn (191)
80Cu (191)
80Ni (191)80Ga (191)
≈25 keV precision
TOF - 4186.72 us TOF - 4186.72 us
Summary MRTOF is compatible to short-lived nuclei Efficient mass spectrograph (multiple nuclides at once) Precise and Accurate (novel referencing method) Applicable to Super Heavy Elements Compatible also to r-process, rp-process nuclides
Collaborators for the SHE-Mass projectM. Wada, P. Schury, Y.Ito, F. Arai, S. Kimura, D. Kaji, H. Haba, K. Morimoto, M. Rosensuch, I.Murray,
J.Y.Moon, T. Niwase, S. Ishizawa, T. Tanaka, A.Takamine, M. Reponen, T. Sonoda, Y. Hirayama, Y.X. Watanabe, H. Miyatake, M. MacCormick, H. Koura, K. Morita, A. Ozawa, H. Wollnik
Wako_Nuclear Science Center, IPNS, KEK Nishina Center for Accelerator-based Science, RIKEN Institute of Physics, Tsukuba University Advanced Science Center, Japan Atomic Energy Agency Department of Physics, Kyushu University Institute of Basic Science, Korea University Paris-Scaley, France New Mexico State University, USA