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

mn =0m

n =2 eV Qmn

status on antineutrino mass

the smaller the Q-value the higher the sensitivity

3H (Q=18.6 keV) 187Re (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 227Kraus Ch et al 2005 Eur. Phys. J. C 40 447

QECmn

status on neutrino mass

the smaller the QEC-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 163Ho

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

status on neutrino mass

163Ho is by far the best candidate QEC-B ≈ 0.5 keV

potential candidates

194Hg and 202Pb also arevery promising nuclides !!!

PROPOSAL P-242 (2008)

“A determination of the Q-values of ECin 194Hg & 202Pb by direct Penning trap

mass measurements of 194Hg/Au and 202Pb/Tl “

status of proposal

ISOLTRAP beam times scheduled for IS473Beam time Dedicated

forTarget/ion source Remark

May 2008 202Pb,202Tl UCx/Hot plasma canceled due to power failure

July 2008 194Au UCx/RILIS successful

August 2008

194Hg UCx/Hot plasma by-product of experiment IS461; successful

October 2008

202Pb UCx/Hot plasma by-product of IS463; successful

April 2009 194Hg UCx/Hot plasma unsuccessful; no 194Hg was seen

June 2011 202Pb202Tl

UCx/RILISUCx/Surface ionization

direct measurement of the QEC-value. The QEC-value is measured with insufficient accuracy

Masses of three out of four nuclides have been measured !!! 194Hg/Au and 202Pb

The Q-value of EC in 194Hg has been determined !!!

status of proposal

AME2003 Q-value of EC in 194Hgis (69±14) keV

New Q-value of EC in 194Hg is (29±4) keV

old scheme of EC in 194Hg new scheme of EC in 194Hg

?

QEC – BL1 = (15 ± 4) keV → It is possible to improve the upper limit onneutrino mass from 200 eV to 20 eV with

this nuclide

Eliseev S et al 2010 Phys. Lett. B 693 426

addendum 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“

Beam time request

Nuclide Ion Source TargetExpected yield,

ions/mCReference masses № of Shifts

202Tl RILIS UCx 1·105 (RILIS) 133Cs 5*

* The number of shifts requested is based on the experience acquired during the previous runs