ROGER CABALLERO FOLCH, FRS User meeting GSI, 28 th November 2011 S410 EXPERIMENT GSI – SEPTEMBER 2011

Introduction and astrophysics motivation Setup: FRS – SIMBA – BELEN Current analysis status and its outlook Contents 1/14 AnalysisFuture goalsIntroductionSetup Summary and future goals

Experiment 2/14 S410: Beta-decay measurements of new isotopes near the third r-process peak (N~126) - Performed at GSI in September 2011 with a week of beam time - Shared setup with S323 experiment The measurements settings were centered on two isotopes: 215 Tl, 211 Hg. We have preliminarily identified the following nuclei: Hg Au 203,206 Pt 199,202 Ir Tl AnalysisFuture goalsIntroductionSetup Introduction

Motivation 3/14 Nuclear structure knowledge:  beta decay studies of these nuclei provide information about their decay mechanism and nuclear structure in this mass region Half lives (T 1/2 ) Beta delayed neutron emission probabilities (P n ) Astrophysics (r-process): nucleosynthesis aspects of the heavy mass elements. The new values for T 1/2 and Pn, will provide valuable information for the test of theoretical models. AnalysisFuture goalsIntroductionSetup Introduction “Ignorance”-Curve Exp. T. Kurtukian et al. Phys. Lett. B (Submitted) DF3 + QRPA + FRDM + QRPA (P.Moeller, et al. 2003) (I.Borzov, et al. 2003)

State of the art 4/14 AnalysisFuture goalsIntroductionSetup N=126 t 1/2 existsidentified Area of interest P n (%) QRPA B n = 2-3 MeV Centered Introduction

AnalysisFuture goalsIntroductionSetup 5/14 Setup Fragment separator spectrometer (FRS). Beam characteristics. SIMBA + BELEN 1.6 g/cm 2 Be target 2x10 9 ions/spill intensity Bρ settings for: 215 Tl, 211 Hg and as references 216 Po, 205 Bi, 135 Sb Spill length ~1s with a period around 4s Separation in flight Bρ – ΔE – Bρ Introduction

Experimental hall (S4) configuration and setting s 6/14 TPC MUSIC SLITS SCI DEGRADER ITAG SIMBA & BELEN AnalysisFuture goalsIntroductionSetup

Implantation detector: SIMBA (Silicon Implantation Detector and Beta Absorber) 7/14 SIMBA detector Multilayer silicon detector Allows to measure both ion implants and β-decays. Decay events can be correlated in time with the detection of neutrons. 2 SSSD (7 segm.) 60x40 mm 2 (1mm thick) XYFRONTA B CREAR Tracking layers XY (60 segm.) 60x60 mm 2 (0.3mm thick) 2 SSSD (7 segm.) 60x40 mm2 (1mm thick) 3 DSSD (implantation area, 60x40 segm.): 60x40 mm 2 (0.7mm thick) Front view AnalysisFuture goalsIntroductionSetup

8/14 Neutron detector: BELEN (Beta Delayed Neutron Detector) - Neutron detector designed by UPC GRETER research group (Barcelona) - The detection of the neutron is based on the detection of products of the reaction of the neutron with 3He counters: 3 He + n  3 H + 1 H keV Ion beam n n n Polyethylene moderator Proportional 3 He counter Silicon β decay detector He counters: AnalysisFuture goalsIntroductionSetup

8/14 Neutron detector: BELEN (Beta Delayed Neutron Detector) BELEN-30 neutron detector · 10 with 10 atm pressure · 20 with 20 atm pressure Neutron shielding SIMBA inside the matrix BEAMLINE AnalysisFuture goalsIntroductionSetup

AnalysisFuture goalsIntroductionSetup Analysis procedure (Preliminary plots / ongoing) 9/14 Analysis Setup Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features A/Q Bi Pb Tl Hg Au Pt Po 215 Tl FRS setting 215Tl SCI21-SCI41  ToF TPC21-22 – TPC41-42  Position calibration MUSIC  Energy Loss calibration PRELIMINARY

AnalysisFuture goalsIntroductionSetup 9/14 Analysis Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Bi Pb Tl Hg Au Pt Po Ir Analysis procedure (Preliminary plots / ongoing) SCI21-SCI41  ToF TPC21-22 – TPC41-42  Position calibration MUSIC  Energy Loss calibration FRS setting 211Hg A/Q 211 Hg PRELIMINARY

10/14 AnalysisFuture goalsIntroductionSetup Analysis Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features 205 Bi setting has been used as Z identification reference via isomer gamma rays and 216 Po setting as A/Q checking in the region of interest. Analysis procedure (Preliminary plots / ongoing) A/Q Z 205Bi keV Counts

11/14 AnalysisFuture goalsIntroductionSetup Analysis Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Implants keV Ch Beta disintegrations - SIMBA c alibrations are being performed with a 137 Cs source - β - decay curves will provide half lives values Implantation Counts Energy deposited (ch) Noise Beta decay Analysis procedure (Preliminary plots / ongoing)

-Time correlation between neutron and beta decay Cf for BELEN efficiency and can be checked with 135 Sb 12/14 AnalysisFuture goalsIntroductionSetup Analysis Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Pulser Noise Neutron signal Counts Energy (ch) Analysis procedure (Preliminary plots / ongoing)

DDAS -Triggerless digital data acquisition system used for the first time in this type of experiments at GSI. -It allows to eliminate the dead time of conventional acquisition systems thanks to the double memory digital cards which allow to acquire data and reading of previously taken data at the same time. -Advantages: 1.Increase the efficiency by about 8% (from 27 to 35%) 2.Flexibility for large time correlation (fundamental to obtain correlations with all neutron and to change the gates offline) 3.Allows to correct some experimental effects, e.g. To reduce neutron background from uncorrelated neutrons. 13/14 AnalysisFuture goalsIntroductionSetup Analysis Tracking detectors calibrations & particle ID Particle ID check via 205 Bi isomers, 216 Po α-decays SIMBA calibration implantation patterns Analysis of half lives and Pn Digital data acquisition system features Analysis procedure (Preliminary plots / ongoing)

Outlook 14/14 AnalysisFuture goalsIntroductionSetup Future goals Analysis  Improved ID-Plot via final calibrations of frs detectors  Determine implantation rates for each identified isotope  Determine implant-beta correlations and neutron-beta correlations  Implement an analysis method for deriving half-lifes and for determining beta-delayed neutron emission probabilities.  In collaboration with theoreticians, study the impact of these results on nuclear models, as well as on r-process nucleosynthesis calculations. Future goals  Upgrade of detector: up to 90 counters (detection efficiency ~70%): collaboration with Dubna  Combine with AIDA implantation detector (first separate tests in August 2011): talk Robert Page (Tue, 10:10)  Optimize detection system (BELEN) and its acquisition (DDAS) for future experiments with more exotic beams (FAIR).  Prepare for first experiments closer to the r-process (>2018)  Measure P xn

The end! Thanks to collaborators: Institut de Física Corpuscular de València (IFIC) Universitat Politècnica de Catalunya (UPC) Helmholtzzentrum für Schwerionenforschung GmbH (GSI) NSCL, Michigan State University (MSU-USA) CIEMAT (Madrid) Universidade de Santigo de Compostela (USC) Department of Physics, University of Surrey (UK) CFNUL Universidade de Lisboa (Portugal) School of Physics & Astronomy, U. Edinburgh (UK) Department of Physics, University of Liverpool (UK) STFC, Daresbury Laboratory (UK) Laboratori Nazionali di Legnaro, INFN (Italy) Flerov Laboratory, JINR, Dubna (Russia) CENBG, Université Bordeaux (France)

State of the art 4/16 Analysis statusData analysisIntroductionSetup Outlook & future Introduction Effect of half-lives The Astr. Jour., 579 (2002), H. Schatz et al. Proc. CGS-13 (2009), G. Martinez-Pinedo “Ignorance”-Curve Focus of present proposal r-path

State of the art 4/14 AnalysisFuture goalsIntroductionSetup Introduction FRDM + QRPA K.-L. Kratz, (private communication) r-process path T 1/2 PnPn Exp. T. Kurtukian et al. Phys. Lett. B (Submitted) DF3 + QRPA+ FRDM + QRPA (P.Moeller, et al. 2003) (I.Borzov, et al. 2003) Effect of half-lives The Astr. Jour., 579 (2002), H. Schatz et al. Proc. CGS-13 (2009), G. Martinez-Pinedo K.-L. Kratz, (private communication)

Particle identification 9/16 Analysis statusData analysisIntroductionSetup Outlook & future Analysis status The method is based in Time of Flight (ToF) measurement according to the energy loss (ΔE) in the (MUSIC) ionisation chambers and the B fields (Bρ) set. 205 Bi setting has been used as Z identification reference via isomer gamma rays and 216 Po setting as A/Q checking in the region of interest. A/Q Z 205Bi keV Counts Setup