SEARCH FOR NEW CANDIDATES FOR THE NEUTRINOORIENTED PRECISION MASS SPECTROMETRY D Beck K Blaum M Block Ch Böhm Ch Borgmann M Breitenfeldt S Eliseev V Fedoseev ID: 778729
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Slide1
Addendum to Proposal P-242 to the INTC
SEARCH FOR NEW CANDIDATES FOR THE NEUTRINO-ORIENTEDPRECISION MASS SPECTROMETRY
D. Beck, K. Blaum, M. Block, Ch. Böhm, Ch. Borgmann, M. Breitenfeldt, S. Eliseev, V. Fedoseev, S. George, F. Herfurth, A. Herlert, H.-J. Kluge, M. Kowalska, S. Kreim, D. Lunney, V. Manea, S. Naimi, D. Neidherr, Yu. N. Novikov, M. Rosenbusch, S. Schwarz, L. Schweikhard, M. Seliverstov, A. Sokolov, J. Stanja, F. Wienholtz, R. N. Wolf, K. Zuber
Spokesperson: Sergey EliseevMax-Planck Institut für Kernphysik, Heidelberg, Germany
MPIK-GSI-Mainz-Leuven-CERN-MSU-FAIR-Orsay-RIKEN-PNPI-Greifswald-Dresden
Slide2m
n
=0
m
n
=2 eV
Q
m
n
status on
antineutrino
mass
the smaller the
Q-value
the higher the sensitivity
3
H (
Q
=18.6 keV)
187
Re (Q=2.57 keV)
Recent
limit of m(νe) ≈ 2 eV is obtained from the analysis of the end point of b--decay
There are
only two suitable candidates
Limited number of suitable nuclides is a substantial restriction for future experiments!
Lobashev
V M
et al
1999
Phys.
Lett
.
B
460
227
Kraus
Ch
et al
2005
Eur. Phys. J.
C
40
447
Slide3Q
EC
mn
status on
neutrino
mass
the smaller the
Q
EC
-B
the higher the sensitivity
The
most
recent
limit
of
m(νe) ≈ 200 eV is obtained from the analysis of
de-excitation spectrum of electron capture (EC) in 163
Ho
There are
a lot of potentially suitable candidates !!! but the choice of the suitable ones is hampered by poor knowledge of their Q-values
B
-binding energy of captured electron
De Rujula A et al 1982 Phys. Lett. B 118 429Springer P T et al 1987 Phys.
Rev
.
A
35
679
Slide4status on
neutrino mass
163Ho is by far the best candidate
QEC-B ≈ 0.5 keV
potential candidates
194
Hg and
202
Pb also are
very promising nuclides !!!
PROPOSAL P-242 (2008)
“A determination of the Q-values of EC
in
194
Hg
&
202
Pb by direct Penning trap
mass measurements of
194Hg/Au and
202Pb/Tl “
Slide5status of proposal
ISOLTRAP beam times scheduled for
IS473Beam timeDedicated for
Target/ion source
Remark
May 2008
202
Pb,
202
Tl
UC
x
/Hot plasma
canceled due to power failure
July 2008
194
Au
UC
x
/RILIS
successful
August 2008
194
Hg
UC
x
/Hot plasma
by-product of experiment IS461;
successful
October 2008
202
Pb
UC
x
/Hot plasma
by-product of IS463;
successful
April 2009
194
Hg
UC
x
/Hot plasma
unsuccessful; no
194
Hg was seen
June 2011
202
Pb
202
Tl
UC
x
/RILIS
UC
x
/Surface ionization
direct measurement of the
Q
EC
-value. The
Q
EC
-value is measured with insufficient accuracy
Masses of
three
out of
four
nuclides have been measured !!!
194
Hg/Au and 202Pb
The Q-value of EC in
194
Hg has been determined !!!
Slide6status of proposal
AME2003 Q-value of EC in
194Hgis (69±14) keVNew Q-value of EC in 194Hg is (29±4) keV
old scheme of EC in 194Hg
new scheme of EC in
194
Hg
?
Q
EC
– B
L1
= (15
± 4) keV
→
It is possible to improve the upper limit on
neutrino mass from 200 eV to 20 eV with
this nuclide
Eliseev
S
et al
2010
Phys.
Lett. B
693 426
Slide7addendum to proposal
In order to determine the Q-value of EC in
202Pb, it remains to only measure the mass of 202Tl Addendum to Proposal P-242“Determination of the mass of 202Tl at ISOLTRAPwith an accuracy of 2
keV“
Slide8Beam time request
Nuclide
Ion SourceTarget
Expected yield, ions/mC
Reference masses
№ of Shifts
202
Tl
RILIS
UC
x
1
·
10
5
(RILIS)
133
Cs
5
*
*
The number of shifts requested is based on the experience acquired during the previous runs