Timeofflightmassmeasurementsforastrophysics AlfredoEstrade - - PowerPoint PPT Presentation

▶
time of flight mass measurements for astrophysics
SMART_READER_LITE
LIVE PREVIEW

Timeofflightmassmeasurementsforastrophysics AlfredoEstrade - - PowerPoint PPT Presentation

Oct 27, 2022 253 likes •447 views

Timeofflightmassmeasurementsforastrophysics AlfredoEstrade St.MarysUniversityandGSI Darmstadt,Oct12 th 2011 Outline BasicprinciplesofTimeofflight(TOF)mass

slide-1
SLIDE 1

Time‐of‐flight
mass
measurements
for
astrophysics


Alfredo
Estrade
 St.
Mary’s
University
and
GSI
 Darmstadt,
Oct
12th
2011


slide-2
SLIDE 2

Outline


  • 
Basic
principles
of
Time‐of‐flight
(TOF)
mass


measurements.


  • 
Recent
results.

  • 
Perspectives.

slide-3
SLIDE 3

Principles
of
time‐of‐flight
(TOF)
measurements


RI
beam
 production
 RI
beam
 production


revolution
frequency
(f)


TOF
start
 TOF
stop


TOF
+
momentum
measurement


momentum
(Bρ)
 measurement


Multi‐turn
measurements
at
storage
rings


Beam
cooling




Isochronous
optics
 (Schottky)




















 Measure
mass
relative
to
isotopes
in
the
beam
 with
well
known
masses
(calibration
masses).



slide-4
SLIDE 4

Main
features
of
TOF
mass
measurements


  • 
Sensitive
technique
can
reach
masses
of
very
unstable
nuclei
(few
100s
to


few
1000s
ions
required).


  • 
Well
suited
to
fast
beams,
as
in
new
generation
radioctive
ioen
beam


facilities
(RIBF,
FAIR,
FRIB).


  • 
Allows
to
map
large
regions
of
the
nuclear
chart
by
measuring
several


masses
simultaneously.
 Some
typical
parameters:


Technique
 TOF‐Br
 Storage
ring
‐
 Isochronous
 Storage
ring
‐

 cooled
beam
 Resolving
power
 (Δm/m)
 1.e‐4
 5.e‐6
 1.e‐7
 Mass
uncertainty
 200
keV
 100
keV
 10
keV
 Measuring
time
 μsec
 μsec
 sec


slide-5
SLIDE 5

Recent
and
current
programs
of
TOF
measurements


MSU,
USA
 (TOF‐Bρ)
 GANIL,
France
 (TOF‐Bρ)
 LANL,
USA
 (isochr.
TOF)
 IMP,
China
 (storage
ring)
 GSI,
Germany
 (storage
ring)
 S
 RIKEN,
Japan
 (TOF‐Bρ, , storage
ring?)
 Green:
program
discontinued.
 Red:
currently
active
facilities.


slide-6
SLIDE 6

Experimental
setup
at
NSCL


‐ 
58
m
path
length,
TOF
≈
450
ns.
 ‐ 
fast
plastic
scintillators
for
timing
(TOF
 resolution
80
ps;

dTOF/TOF
≈
2e‐4)
 ‐ 
microchannel
plate
‐detectors
for
position
 (momentum).


2.4
 2.45
 2.5
 2.55
 2.6
 2.65
 440
 445
 450
 455
 460
 465
 470
 475
 480
 Mass
to
Charge
[amu/q]
 TOF
[ns]


unknown
masses
 calibration
masses


slide-7
SLIDE 7

First
results
from
TOF
experiments
at
NSCL


A.
Estrade
et
al,
to
be
published
in
PRL
(arXiv:1109.5200)







impact
on
nuclear
processes
in
accreting
NS.


Two
neutron
separation
energy
measures
binding
energy
of
last
two
neutrons:
 S2n
=
M(A‐2,Z)
‐
M(A,Z)
+
2
M(n).
 Slope
change
indicates
onset
of
deformation.


slide-8
SLIDE 8

First
results
from
TOF
experiments
at
NSCL


A.
Estrade
et
al,
to
be
published
in
PRL
(arXiv:1109.5200)







impact
on
nuclear
processes
in
accreting
NS.


Two
neutron
separation
energy
measures
binding
energy
of
last
two
neutrons:
 S2n
=
M(A‐2,Z)
‐
M(A,Z)
+
2
M(n).
 Slope
change
indicates
onset
of
deformation.


slide-9
SLIDE 9

Constraints
for
nuclear
mass
models


‘Calc.’=
Finite
Range
Droplet
Model


slide-10
SLIDE 10

Constraints
for
nuclear
mass
models


Figure
courtesy
of
P.
Moeller.


slide-11
SLIDE 11

Radioactive
Ion
Beam
Factory
at
RIKEN


slide-12
SLIDE 12

r‐process
experiments
at
RIKEN


Recent
Penning
trap
measurements
near
N=60
 ‐
U.
Hager
et
al,
PRL
96,
042504
(2006)
 ‐
U.
Hager
et
al,
PHYSICAL
REVIEW
C
75,
064302
(2007)
 ‐
S.
Rahaman
et
al,
Eur.
Phys.
J.
A
32,
87–96
(2007)
 ‐
P.
Delahaye,
PHYSICAL
REVIEW
C
74,
034331
(2006)


Atomic
mass
 evaluation
(2003)
 known
half‐life
 S.
Nishimura
et
al,
PRL
106,
052502
(2011)


slide-13
SLIDE 13

Synchrotron accelerator

Experimental
Storage
Ring
(ESR)
at
GSI


slide-14
SLIDE 14

Mass
measurements
towards
r‐process
path
at
GSI
 B.
Sun
et
al.,
Nuclear
Physics
A
812
(2008)
1–12


Recent
storage
ring
results


see
also
(U
fragments):
 L.
Chen,
et
al,
Phys.
Lett.
B
 691
(2010)
234.


First
mass
measurement
at
IMP

 (proton‐rich
A=2Z‐1
nuclei)


X.
L.
Tu
et
al,
PRL
106,
112501
(2011)


Physics
result:
64Ge
not
significant
 rp‐process
waiting
point.


slide-15
SLIDE 15

Summary
of
recent
TOF
mass
measurements
relevant
to
 nuclear
astrophysics


IMP
(CSRe
IMS)
 2003
Atomic
Mass
Evaluation
 classical
r‐process
path
 NSCL
(TOF‐Brho)
 GSI
(ESR
IMS)
 GSI
(ESR
SMS)


slide-16
SLIDE 16

Production
of
new
isotopes


Discovery
of
130
new
isotope
in
the
recent
literature:


GSI:
H.
Alvarez‐Pol
et
al.,
Phys.
Rev.
C
82,
041602(R)
(2010)
 T.
Kurtukian‐Nieto,
J.
of
Phys.:
Conf.
Series
202
(2010)
012012
 NSCL:
O.
Tarasov
et
al.,
PRL
102,
142501
(2009)
 RIKEN:
T.
OHNISHI
et
al.,
J.
of
the
Phys.
Soc.
of
Japan
79
(2010)
073201
 2003
Atomic
Mass
Evaluation
 Recent
TOF
mass
measurements
 classical
r‐process
path


slide-17
SLIDE 17

Production
of
new
isotopes


Discovery
of
130
new
isotope
in
the
recent
literature:


GSI:
H.
Alvarez‐Pol
et
al.,
Phys.
Rev.
C
82,
041602(R)
(2010)
 T.
Kurtukian‐Nieto,
J.
of
Phys.:
Conf.
Series
202
(2010)
012012
 NSCL:
O.
Tarasov
et
al.,
PRL
102,
142501
(2009)
 RIKEN:
T.
OHNISHI
et
al.,
J.
of
the
Phys.
Soc.
of
Japan
79
(2010)
073201
 2003
Atomic
Mass
Evaluation
 Recent
TOF
mass
measurements
 classical
r‐process
path
 IMP
(CSRe
IMS)
 NSCL
(TOF‐Brho)
 GSI
(ESR)
 RIKEN
(TOF‐Brho)


?
 ?


slide-18
SLIDE 18

S800
spectrometer
,NSCL
 Penning
Trap
 ESR
Electron
cooler,
GSI
 MR‐TOF
spectrometer,
U.
Giessen


Conclusions


‐ Time‐of‐flight
mass
measurements
well
suited
to
measure
masses
of
very
 unstable
nuclei
for
astrophysics
applications.
 ‐ 
Offer
a
complementary
approach
to
other
mass
measurement
techniques
 (traps).
 ‐ 
Measurement
programs
currently
active
at
several
facilities
around
the
 world
(GSI,
NSCL,
IMP,
RIKEN).