TOF Mass Measurements: Status and Future (or When the Masses of the R-Process Nuclides will be Measured?) Milan MATOŠ A
Jan 21, 2016
TOF Mass Measurements: Status and Future
(or When the Masses of the R-Process Nuclides will be Measured?)
Milan MATOŠ
JINA Frontiers August 20, 2007
Known Masses (AME 2003)
r-process
ETSFI-Q dripline
Mass Measurement TechniquesPenning traps Time-of-Flight
very precise ~ 1 keV less precise ~100 keV
half life > 10 ms half life > 1s
rate > 100 part/s after the nuclide production
rate > 0.01 part/s after the nuclide production
complex simple
expected to be first to measure r-process masses
Principle of Time-of-Flight Mass Measurements
vq
mB t
Lv
constB
constL
tconstq
m
constB usually B acceptance ± several percent
solutions
B measurement
constL
B
isochronicity
t constant for fixed m/qeven if v1 < v2
xB
dispersive mode
Existing Time-of-Flight Mass
Measurement Facilities
B measurement isochronicity
multi-turnlinear
flight path
B distribution
TOFI at Los Alamos
SPEG at GANIL
TOF start
length ~82m
position (B )
target
TOF stop
position (B )dE-E (identification)
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
productiontarget
10m
Isochronous Mass Spectrometryin ESR (at GSI)
In jectionIn jectionIn jection
tim e [ s]
U [V ]
0 1 2
0
-0.5
tim e [ s]
U [V ]
0 1 2
0
-0.5
IMS at GSI
TOF-Bat the NSCL
10m
K500
K1200 A1900
transfer hall
S800TOF startTOF stop
B meas.
path length ~ 58m
fast PMTs:Timing Resolution ~ 30ps
MCP: Position Resolution
< 0.5mm
see next talkby A. Estrade
Comparisons
TOFI
at LANL
SPEG
at GANIL
SMS
at GSI
TOF-B
at NSCL
B
distributionisochron. Br meas. isochron. Br meas.
flight path N/A 82m 100 x 108m 58m
relative
resolutionN/A 1x10-4 2x10-5 1x10-4
relative
uncertainty2x10-6 1-2x10-6 1-2x10-6 1-2x10-6
typical
energyN/A 40 MeV/u 350MeV/u 100MeV/u
Isochronicity vs. B measurement
Comparisons
easy to set updifficult to set up
no B measurement needed (no detector) position sensitive required
low large energy losses in detectorslarge energy losses in detectors
low energy vs. high energylow charge contaminationlarge charge contamination
unlimited m/q range for one settinglimited m/q range for one setting
linear vs. multi-turn
shorter flight timelonger flight time
better resolutionworse resolution
limitation on total statistics < 10ppstotal statistics < 1000pps
isomeric contamination:resolved for E > 500keV
isomeric contamination:fully covered by detectors
transmission ~ 0.1%transmission ~ 10%
TOF (yellow) vs. Penning traps (blue)
RIKEN – BigRIPS
RIKEN – BigRIPS+ ZDSE ~ 350MeV/A
TOF start/stop (88 m)
B measurement
FAIR – isochronous CR E ~ 1.5GeV/A
ILIMA project
ISF at MSU
E ~ 250MeV/A
ISF at MSU
E ~ 250MeV/A
Future Facilities Rates
FAIR: 2012 first experiments 2015 completion
ISF: 2016 if approved
Big RIPS: 2007 first experiments
timelines
rate needed ~ 0.01pps
rate needed ~ 0.01ppsrate needed ~ 0.1pps
Conclusions
in 5 years – first large r-process areas by RIKEN Z < 40 & Z~50in 10 years – Z < 40 & Z~50 fully covered by MSU or GSIIn 15 years – Penning trap measurements in the r-process area
penetration into more exotic r-process areas In 20 years – ????
• competition has already started• who will be the winner? depends on decisions • many surprises are expected• theoreticians (nuclear models, r-process) should be prepared
JINA should be involved