N126 factory and rprocess Guy Savard Scientific Director

N=126 factory and r-process Guy Savard Scientific Director of ATLAS Argonne National Laboratory & University of Chicago ATLAS Users Meeting ANL, May 15 -16, 2014

R-process sensitivity to nuclear physics input Hot r-process Supernova neutrinodriven wind cold r-process Neutron-star merger cold rprocess binding energy neutron-capture rate lifetime From R. Surman, M. Mumpower et al, ar. Xiv: 1039. 0059 v 1 ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 2

1 Ge. V/u 238 U + 1 H Armbruster et al. 238 U § difficult to reach via fragmentation § cannot be reached via fusion § unique physics, critical to the r-process, which is wide open for a facility able to reach there, even in the FRIB era ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 3

Producing neutron-rich N=126 nuclei § Production using deep-inelastic reaction: e. g. : 136 Xe at 9 Me. V/u and 5 pm. A on a 10 mg/cm 2 198 Pt rotating target Calculated using GRAZING (http: //personalpages. to. infn. it/~nanni/grazing) All of these isotopes, except for 204 Pt, are unknown … no mass, lifetime or decay properties known Extracted beam: ~ 15% of production ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 4

Collecting the N=126 recoils § § § Deep inelastic reactions used in the past to produced n-rich isotopes, the products identified in complex setups (Mayer 1985, Corradi 1999, …), but no system has so far been able to collect them efficiently. But the cross-section are high and with high primary beam intensity and efficient collection efficiency sizable yield in unexplored n-rich regions are reachable Proposed collection system capitalizes on • High primary beam intensity • High -intensity gas catcher technology § Feed low-energy systems: mass measurements, decay spectroscopy, … target-like recoils beam dump extracted recoils 136 Xe to selection stage rotating 198 Pt target ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 5

The CPT-II apparatus and low-energy stations for deep-inelastic reaction products Decay Station § Designed to push back space charge limit – RFQ ion guide now operating in DC mode to avoid space charge build up – Rough mass separation by inflight mass separator before isobar separator – Rest of system essentially the same § § Mass separator (DM/M ~ 1/1000) ATLAS Users Meeting Guy Savard, Argonne National Laboratory Can operate at up to 5 -50 pm. A while still providing required selection before precision Penning trap Deep inelastic reactions down to ~0. 01 mb … around 198 Hf on N=126 line May 15 -16, 2014 6

Existing target wheel can handle expected highintensity beams § Even with the most volatile metals, existing large rotating wheel can handle 10 pm. A Courtesy of F. Pellemoine (GANIL) § For typical metal targets with melting points above 1000 C, can handle 100 pm. A. ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 7

Mass measurements of neutron-rich nuclides • Masses determined via a measurement of the ions’ cyclotron frequency • Can measure the mass with a production rate of ~ 1 ion / s • Mass precision ~ 10 -7 to 10 -8 (10 -100 ke. V/c 2) for masses approaching the r process • Canadian Penning Trap (CPT) has measured more than 100 neutron-rich nuclides, including more than 70 from CARIBU (including 6 isomers) Original • ~ 20 had never been previously measured by any technique Area II 2012 CARIBU 2013 • Currently reaching isotopes produced at the 10 -6 fission branch level • For some nuclei, no prior information on the nuclide existed! ATLAS Users Meeting Guy Savard, Argonne National Laboratory J. Van Schelt et al. , Phys. Rev. C 85, 045805 (2012) May 2014 J. 15 -16, Van Schelt et al. , Phys. Rev. Lett. 111, 061102 (2013) 8

Comparison with the 2003 atomic mass evaluation J. Van Schelt et al. , Phys. Rev. C 85, 045805 (2012) J. Van Schelt et al. , Phys. Rev. Lett. , submitted (2013) Sn Sb Te I Xe Cs Pr Nd Pm Sm Eu Gd Less binding In Higher N • Trends indicate nuclei are less bound with neutron excess (affects the location of the rprocess path • Good agreement with other Penning trap results and reaction Q value measurements • Large disagreement with results obtained with βdecay measurements ATLAS Users Meeting Guy Savard, Argonne National Laboratory 9

Low-energy experimental equipment Beam properties § Delivers 1. 5 k. V to 10 k. V beam to experimental stations • Pulsed beams with rates from ~ 50 ms to seconds • Low emittance • High purity • Experimental stations: CPT LASER LAB BPT X-ARRAY (installed) • Limited amount of space … but by now we are used to that ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 10

Status § Main components are being constructed § Production system will be installed in experimental area III in early 2015 § CPT moved to this area later in 2015 to start mass measurement program in this region § Low-energy beamline to deliver these beams to various experiments to be stationed temporarily in area III to follow. Provides: – Unique beams – High purity – Not high intensity but far reaching so well suited to sensitive low-energy experiments ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15 -16, 2014 11