precision mass measurements for nuclear...
TRANSCRIPT
Canada’s National Laboratory for Particle and Nuclear Physics Laboratoire national canadien pour la recherche en physique nucléaire
et en physique des particules
Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada
Propriété d’un consortium d’universités canadiennes, géré en co-entreprise à partir d’une contribution administrée par le Conseil national de recherches Canada
Precision mass measurements for
nuclear physics
J. Dilling
TRIUMF is owned & operated by a consortium of 19 universities
Founded 45 years ago in Vancouver
Members University of Alberta
University of BC
Carleton University
University of Guelph
University of Manitoba
Université de Montréal
Queen’s University
Simon Fraser
University of Toronto
University of Victoria
York University
Canada’s National Laboratory for
Particle and Nuclear Physics
Associate Members University of Calgary
McMaster University
University of Northern BC
University of Regina
Saint Mary’s University
University of Winnipeg
McGill University
Western University
ISAC
Highest Power ISOL RIB
facility
- Nuclear Structure
- Nuclear Astrophysics
- Fund. Symmetries
- CMMS (bNMR)
Nordion
commercial medical
isotope production
3 cyclotrons
CMMS
Centre for Molecular and
Material Science (mSR)
Particle Physics
Pienu (- 2012)
Ultra Cold Neutrons (2015 -)
Cyclotron
500 MeV
350 mA
ISAC-I
60 keV,
1.7 AMeV
ISAC-II
>10 AMeV 40 MV SRF
Heavy Ion Linac
Advanced Rare
Isotope Laboratory
(ARIEL)
e-LINAC
300-500 kW
photo-fission
driver
(2015-2017)
ISOL facility with highest primary
beam intensity (100 mA, 500 MeV, p)
Programs in
• Nuclear Structure & Dynamics
• Nuclear Astrophysics
• Electroweak Interaction Studies
• Material Science
ISAC I:
60 keV & 1.7 AMeV
ISAC II:
10 AMeV for A<150
16AMeV for A<30
DESCANT GRIFFIN
expand RIB program with:
• 3 simultaneous beams
• increased number of
hours delivered per year
• new beam species
• enable long beam times
(nucl. astro, fund. symm.)
• increased beam
development capabilities
New electron linac driver
for photo-fission
New proton beamline
staged installation
started 2012
Cyclotron Vault (exiting)
RIB front end
Electron Hall
Target Hall
October 1st:
22.9 MeV e-beam
ARIEL, Civil construction and eLINAC
ARIEL: e-linac for photo-fission total power: 0.5 MW
Photo-fission products using 50 MeV 10 mA electrons on Hg convertor & UCx target.
up to 1014 fissions/s
100 kW, 25 MeV electrons by 2014 500 kW, 50 MeV electrons by 2017
TIMELINE:
• 2014 first beam, target R&D
• 2017 new front end (phase II)
• 2017 physics production 8Li
• 2018 photo fission
• 2020 proton beam (3 beams)
Mass difference of 2 nuclei
gives energy gain in
reactions (like in stars)
and for beta decay
Halos and skins
Element Synthesis
via r-process (supernova)
Evolution of
Nuclear Shells
dm/m = 10-7
10-7< dm/m < 10-6
dm/m < 10-8
10-6< dm/m < 10-5
Abundance vs. A
Binding energy includes
all effective interactions
and reflects the nuclear potential
The nature of neutrinos
and double beta decay
Kepler's supernova
remnant, SN 1604
500 MeV
protons
Mass
Separator
Low-energy beam
transport
TITAN
Programs in
• Nuclear structure &
dynamics
• Nuclear astrophysics
• Electroweak interaction
Studies
• Material science
ISOL facility with highest primary beam
intensity (100 mA, 500 MeV p)
TRIUMF’s Ion Trap for
Atomic and Nuclear
Science
• High-precision mass
measurements
• In-trap decay
spectroscopy
J. Dilling et al., NIMB 204 (2003) 492
RFQ: Accumulation,
cooling, and
bunching
EBIT: ms charge breeding
BNG: fast m/q
selection
MPET: mass
measurement via
cyclotron frequency
determination
Future traps: • MR-TOF MS after RFQ (w/ U. of Giessen)
• Cooler Penning trap before MPET
• Both set-ups installed off-line
z0
r0
ring
electrode
end cap
ions
M. Brodeur et al., PRC 80 (2009) 024314; M. Brodeur et al., IJMS 20 (2012) 310
3.7 T magnet
2pnc = (q/m) B
-100 -50 0 50 100
56
58
60
62
64
Mean T
ime o
f F
light [m
s]
nRF
- 1831558 [Hz]
31Na+
T1/2 = 17 ms
n+ + n- = nc
• Lorentz steerers
• TOF-ICR technique
Fast measurements:
T1/2 ≥ 9 ms (11Li)
Since PT were
developed for ions,
they behave
the same way for
stable or unstable
particles!
Ideal for systematic
test and
optimizations
K. Blaum, J.Dilling,
W. Nörtershäuser,
Phy. Scr. T152 (2013)
K. Blaum et al., EPJ A 15, 245 (2002)
ISOLTRAP: Carbon Cluster tests
(dm/m)res = 8·10-9
B. Brodeur et al., INJM 310, 20 (2012)
TITAN: Global compensation method
ΔR/Rtotal = − 4(6) × 10−12 · Δ(m/q) · V0
V.-V. Elomaa et al., NIM A 612, 97 (2009)
JYFLTRAP: Carbon Cluster tests
σres,lim(r)/r=7.9×10-9
C. Droese et al., NIM A 632, 157 (2011)
SHIPTRAP: Temperature stability
σo=1.3(3)×10−9/h
Reached high accuracy
and precision:
Excellent reliability Other on-line trap systems do this
as well…CPT, LEBIT…
n
NBqTm
RFc
11
ndB
m
qc
pn
2
1
-4
-2
76Rb+12
Demonstrated off-line that 5 ms cycle are possible:
A. Chauduri et al., Applied Physics B (2014) 114, 99
Mg (p-rich, light)
Island of Inversion
• N-deficient Mg isotopes
• N-rich Na, Al, Mg isotopes (IoI)
Mass measurements at A=20,21
• Mass measurements of Mg masses
Technical difficulty: ISOL production is not selective:
• isobars are co-produced with the isotopes of interest!
• Na, closer to stability, and longer-lived
• much more extracted and delivered to
experiment (1.000.000-1 ratio)
• cleaning system required!
Tricks for clean beams:
Go to the source! Ion Guide Laser Ion Source (IG-LIS)
• Suppress normal surface ions (Na).
• Only allow neutral atoms to drift into the laser-ionization region
• Selective ionization of species (Mg)
• Laser ion source still has significant contribution of
surface ions
Performance of the source: IG-LIS
Background reduction of 6 orders of magnitude!
Mg-isotopes
Penning trap mass measurements
M(A,T,Tz) = a(A,T) + b(A,T) Tz + c(A,T) Tz2
• G.S. binding energy
• non-zero d coefficients in all three
multiplets, A=20,0+, A=21,1/2+, 5/2+
• dexp cannot be explained by
USDA/B models
• uncertainties in cEFT calculations
too large to be definitive
20Mg+
20Mg: 45s deviation from
AME12 & 15x improved
precision
21Mg: 14s 22x
improved precision
Compared to USDA/B &
cEFT NN+3N predictions
Excellent collaboration of target/ion source group, experiment and theory
Mass measurements with TITAN:
• Fast (short half-lives !)
• Precise
• Accurate
Island-of-Inversion Mass Cartography
figure from Himpe et al, PLB 658 (2008) 203
•Many with very short T1/2:
• 32Na: 12.9 ms
• 31Na: 17 ms
• 34Mg: 20 ms
2.3s crossover at N = 21:
• Island-of-inversion behavior?
• Isomer?
1Rotaru et al. PRL 109 (2012) 092503
A. Chaudhuri et al, PRC 88 (2013) 054317; A.Kwiatkowski et al, submitted to PLB;
Dn(N
,Z)
=S
2n(N
+2
,Z)
- S
2n(N
,Z)
Proton Number Z
Dn(N=20) falls off in the island of
inversion.
Dn(32Mg) lowest of any magic
number
2.3s crossover at N = 21:
• Island-of-inversion behavior?
• Isomer?
• Island-of-inversion behavior due to
correlation energy
• Isomer would have a smaller effect
• Decay losses excluded 26 ms
state1
J. Dilling et al., NIMB 204 (2003) 492
RFQ: Accumulation,
cooling, and
bunching
EBIT: ms charge breeding
BNG: fast m/q
selection
MPET: mass
measurement via
cyclotron frequency
determination
• Superconducting magnet, Helmholtz configuration
• Design specs up to an electron beam 70 keV & 5 A
• 7 radial ports with recessed Be windows
A. Lapierre et al., NIMA 624 (2010) 54
Sikler lens
cathode
electron gun
500 mA achieved
dm m
m q B TRF N≈
74Rb8+ T1/2 = 64 ms
Heaviest superallowed b emitter
~1/TRF
N limited by yield/beam time
TRF limited by T1/2
B limited by dB/B
q up to Z+
Boost precision
or
Reduce experimental requirements
for the same precision
S. Ettenauer et al., PRL 107 (2011) 272501
A.T. Gallant et al., PRC 85 (2012) 044311
78Rb8+
TRF = 197 ms
isomer g.s.
To measure 71Ge Q-value, needed
to separate small amount of 71Ge
from overwhelming 71Ga
contamination
Exploited Z dependence of charge-
state distribution & large increase in
Ie at closed shells
Ne-like ions could be achieved for Ee
~ 2 keV & Jt ≥ 20 A cm-2 s
predominantly 71Ga21+ and 71Ge22+
(CBSIM simulations allow for a
systematic approach)
A.A. Kwiatkowski, T.D. Macdonald, et al., NIMB 317 (2013 517
M.C. Simon et al., RSI 83 (2012) 02A912, D. Frekers, M.C. Simon, et al., PLB 722 (2013) 233
electron beam
70 mA / 2.0 kV
Me
an
TO
F [m
s]
nRF – 16 821 000 [Hz]
Laser: OFF ON
Q = 21+ 71Ga 71Ga, 71Ge
Q = 22+ – 71Ge
n
s
D. Frekers et al., PLB 706 (2011) 134; D. Frekers, et al., PLB 722 (2013) 233; T.D. Macdonald, et al, PRC 89 (2014) 044318
Confirmation of 71Ga and 51Cr nuclear structure.
The discrepancy persists.
g
444
244
1263
2235
z 30Mg 315(5) ms
30Al 3.6 s
z 30Si
T.A. Hinners et al, PRC 77 (2008) 034305; D.E. Alburger & D.R. Goosman, PRC 9 (1974) 2236
Time of Flight [ms]
ion
s/s
hot
keV
co
un
ts
tCB = 500 ms
tBG = 300 ms
tCB = 50 ms
-150 -100 -50 0 50 100 150
21
22
23
24
Me
an
Tim
e o
f F
ligh
t [m
s]
nRF
- 15 154 066 [Hz]
30Mg8+ tCB = 50 ms
A.A. Kwiatkowski, R. Klawitter, A. Lennarz, et al, in preparation
Preliminary
Time of Flight [ms]
ion
s/s
hot
-100 -50 0 50 10018.8
19.2
19.6
Me
an
Tim
e o
f F
ligh
t [m
s]
nRF
- 20 843 189 [Hz]
30Al11+ tCB = 4 s keV
co
un
ts
tCB = 500 ms
tBG = 300 ms
tCB = 4 s
A.A. Kwiatkowski, R. Klawitter, A. Lennarz, et al, in preparation
Preliminary
n
D. Frekers et al., CJP 85(2007)57; K.G. Leach et al., arXiV 1405.7209
A. Lennarz, et al, Phys. Rev. Lett. 113 (2014) 082502; K.G. Leach et al., arXiV 1405.7209
0-2 s 6-8 s 12-14 s 18-20 s
• RFQ space-charge limit 10.000× smaller
than EBIT
• Inject multiple ion bunches :
• Open trap for singly charged ions
• Close trap for singly charged ions (DV)
• After charge breeding, ions experience
deep potential well (DV∙Q)
K.G. Leach et al., arXiV 1411.4083
RFQ accumulation,
cooling, & bunching
SCI
SCI
HCI
offline
ion source
BNG fast m/q selection
EBIT ms charge breeding &
in-trap decay spectroscopy
MPET high-precision
mass measurement
Multi-Reflection Time-of-Flight Mass Separator: - Tested in Giessen to M/DM ≈ 50 000
- Will improve beam-purity capability from 1:200 to 1:104 desired ion to contamination ratio
- Arrived at TRIUMF 10th of September
- Off-line commissioning Spring 2015, on-line December 2015
Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada
Propriété d’un consortium d’universités canadiennes, géré en co-entreprise à partir d’une contribution administrée par le Conseil national de recherches Canada
Canada’s National Laboratory for Particle and Nuclear Physics Laboratoire national canadien pour la recherche en physique nucléaire
et en physique des particules
TRIUMF:
Alberta | British Columbia | Calgary |
Carleton | Guelph | Manitoba | McMaster |
Montréal | Northern British Columbia |
Queen’s | Regina | Saint Mary’s Simon
Fraser | Toronto | Victoria | Winnipeg | York
TIT
AN
gro
up @
IS
AC
C. Andreoiu, M. Alansarri, J.C. Bale, B.R. Barquest, U. Chowdhury,
A. Finlay, D. Frekers, A.T. Gallant, G. Gwinner, R. Klawitter, B.A.
Kootte, A.Kwiatkowski, D. Lascar, K.G. Leach, A. Lennarz,
E. Leistenschneider, A. Mayer, D.A. Short, J. Dilling
and the TITAN Collaboration