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

2 ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15-16, Pb 238 U Accessing new regions: deep-inelastic reactions to reach the far north-east of the nuclear chart The Science:  nuclear shell structure at the extremes  r-process: second abundance peak, fission recycling and termination  fission barriers of neutron-rich nuclei and symmetry energy  connection of hot-fusion SHE island and mainland  Unusual GT vs 1st forbidden beta decay ratios 2

3 ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15-16, U 1 GeV/u 238 U + 1 H Armbruster et al.  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 3

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

5 ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15-16, 2014 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, … 136 Xe extracted recoils beam dump rotating 198 Pt target to selection stage target-like recoils 5

G. Savard May ATLAS Operation’s Review 6 The CPT-II apparatus and low-energy stations for deep-inelastic reaction products  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 in- flight mass separator before isobar separator –Rest of system essentially the same  Can operate at up to 5-50 p  A while still providing required selection before precision Penning trap  Deep inelastic reactions down to ~0.01  b … around 198 Hf on N=126 line Mass separator (  M/M ~ 1/1000) Decay Station

7 ATLAS Users Meeting Guy Savard, Argonne National Laboratory May 15-16, 2014 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