ROGER CABALLERO FOLCH,

1 de juny de 2012

Introduction: Astrophysics and Nuclear Physics motivation

Experiment: Setup and detectors

BEta deLayEd Neutron detector (BELEN) outlook goals

Contents

Analysis BELENIntroduction Experiment

Analysis - Ongoing work

Current questions in the field of nuclear physics

Analysis BELENIntroduction ExperimentIntroduction

• What are the limits of nuclear existence?

• What is the heaviest element we can make?

• Do new forms of collective motion occur far from the valley of nuclear stability?

• Are there new forms of nuclear matter in very loosely bound nuclear systems?

• How does the ordering of quantum states, with all of its consequent implications for

nuclear structure and reactions, alter in highly dilute or neutron-rich matter?

• Do symmetries seen in near-stable nuclei also appear far from stability and do we

observe new symmetries?

• How are the elements and isotopes found in the Universe formed?

• Where are the sites of the r-process(es) of nucleosynthesis?

• What is the nuclear equation of state for neutron stars?

• etc, etc.

Taken from NUPECC long range plans

Experimental resources

Main Experimental Research Activities

• Nuclear structure and dynamics

• Nuclear astrophysics

• Fundamental interactions

• Nuclear physics tools and applications

Main Research Facilities

• GSI (Germany)

• ISOLDE (CERN)• n_TOFF (CERN)

• Univ. of Jyväskylä(Finland)

• INFN-LNL (Italy)

• GANIL (France)

• …also installations overseas

(TRIUMF, RIKEN, etc.)

Laboratories

• Nuclear force (T=0 pairing)

• Structure of nucleons

• Reactions with exotic (halo) nuclei

• Extending the limits of nuclear chart

• Mass measurements

• Cross section measurements

• Beta decay studies

Analysis BELENIntroduction ExperimentIntroduction

Nucleosynthesis in nature

Fusion in common stars: from H only He & Li are produced CNO cycle. More nuclei with fusion reaction up to Fe.

Beyond Fe nucleosynthesis proceeds through: s-process, r-process, p-process, etc

Analysis BELENIntroduction ExperimentIntroduction

Nucleosynthesis s-process

Analysis BELENIntroduction ExperimentIntroduction

Nucleosynthesis s-process

Analysis BELENIntroduction ExperimentIntroduction

Nucleosynthesis s-process

Analysis BELENIntroduction ExperimentIntroduction

Nucleosynthesis r-process

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1940

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1948

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1958

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1968

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1978

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1988

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 1994

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

Analysis BELENIntroduction ExperimentIntroduction

State of the art: Knowledge of masses through the years

Up to 2004

G. Audi et al., Nucl. Phys. A565, 1(1993); A 595, 409 (1995), A729.337(2003)

About 2200 nuclear masses were measured and 3000 nuclides known of 8000 that are assumed to exist.Still far away from the r-process path,Especially for the heavy nuclides.Future RIB facilities: FAIR and RIKEN

Analysis BELENIntroduction ExperimentIntroduction

FAIR (Facility for Antiproton Ion Research)

Analysis BELENIntroduction ExperimentIntroduction

β,n, γ-decay of exotic (neutron-rich) nuclei...DESPEC requires different types of equipment to study the multiple aspects of the problem

-decay

Beta delayed neutron detectorNeutron spectrometer

with AIDA

Fast timing array

TAS

DESPEC (Decay SPECtroscopy)

Analysis BELENIntroduction ExperimentIntroduction

Neutron emission after β- decay scheme

To measure neutron emission probabilities after beta decay of neutron rich isotopes with

relevance in basic nuclear physics, astrophysics and nuclear technology.

Analysis BELENIntroduction ExperimentIntroduction

neutron BETA

Example of β-delayed neutron emission

Analysis BELENIntroduction ExperimentIntroduction

Motivation

Half lives (T1/2)

Beta delayed neutron emission probabilities (Pn)

Astrophysics (r-process) and nuclear

structure: nucleosynthesis aspects of the

heavy mass elements. Provide valuable

information for the test of theoretical

models.Exp. T. Kurtukian et al.

Phys. Lett. B (Submitted)

DF3 + QRPA

+ FRDM + QRPA(P.Moeller, et al. 2003)

(I.Borzov, et al. 2003)

Analysis BELENIntroduction ExperimentExperiment

S410: Beta-decay measurements of new isotopes near the third r-process peak (N~126)

State of the art

N=126

t1/2 exists identifiedArea of interestPn (%) QRPABn= 2-3 MeV

Centered

Analysis BELENIntroduction ExperimentExperiment

GSI facility. Fragment separator spectrometer (FRS)

Beam characteristics

238U beam 1GeV/n

2x109 ions/s intensity

1.6 g/cm2 Be target

Analysis BELENIntroduction ExperimentExperiment

Fragment separator spectrometer (FRS). Beam characteristics.

SIMBA +BELEN

1.6 g/cm2 Be target

2x109 ions/spill intensity

Bρ settings for: 215Tl, 211Hg and as references 216Po, 205Bi, 135Sb

Spill length ~1s with a period around 4s

Separation in flightBρ – ΔE – Bρ

Analysis BELENIntroduction ExperimentExperiment

Experimental hall (S4) configuration and settings

TPCMUSIC

SLITS

SCI

DEGRADER

ITAG SIMBA &BELEN

Analysis BELENIntroduction ExperimentExperiment

Neutron detector

SIMBA

Pol

yeth

ylen

e sh

ield

ing

Analysis BELENIntroduction ExperimentExperiment

Experimental hall (S4) configuration and settings

Particle Identification (ID)

The separation method based in Time of Flight (ToF) measurement, Energy

Loss (ΔE) in the (MUSIC) ionisation chambers and the B fields (Bρ) set.

Analysis BELENIntroduction ExperimentExperiment

IDENTIFICATION: Z and A/Z

Implantation detector: SIMBA (Silicon Implantation Detector and Beta Absorber)

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 mm2 (1mm thick)

XY FRONT A B C REAR

Tracking layers XY (60 segm.) 60x60 mm2 (0.3mm thick)2 SSSD (7 segm.) 60x40 mm2 (1mm thick)3 DSSD (implantation area, 60x40 segm.): 60x40 mm2 (0.7mm thick)

Front view

Analysis BELENIntroduction ExperimentExperiment

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: 3He + n 3H + 1H + 765 keV

Ion beam

n

n

n

Polyethylenemoderator

Proportional 3He counterSilicon

β decay detector

- 30 3He counters:

Analysis BELENIntroduction ExperimentExperiment

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

Analysis BELENIntroduction ExperimentExperiment

Analysis BELENIntroduction Experiment

Analysis procedure (Preliminary plots / ongoing)

Analysis

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

SCI21-SCI41 ToF

TPC21-22 – TPC41-42 Position calibration

MUSIC 41-42-43 Energy Loss calibration

Angle correction of each particle. TPC information.

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

Analysis procedure (Preliminary plots / ongoing)

Analysis BELENIntroduction Experiment Analysis

Physical effects along time correction.

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

Analysis procedure (Preliminary plots / ongoing)

ID plot evolution in the analysis

Analysis BELENIntroduction Experiment Analysis

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

205Bi setting has been used as Z identification

reference via isomer gamma rays and 216Po setting

as A/Q checking in the region of interest.

Analysis procedure (Preliminary plots / ongoing)

A/Q

Z

205Bi

keV

Cou

nts

Analysis BELENIntroduction Experiment Analysis

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

Implants keV

Ch

Bet

a di

sint

egra

tion

s

- SIMBA calibrations are being performed with a 137Cs source

And alpha lines from a 216Po setting

- β- decay curves will provide half lives values

ImplantationCo

un

ts

Energy deposited (ch)

Noise

Beta decay

Analysis procedure (Preliminary plots / ongoing)

Analysis BELENIntroduction Experiment Analysis

- Time correlation between neutron and beta decay

-252Cf for BELEN efficiency and can be checked with

135Sb

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

N

NP n

nn

1

Pulser

Noise Neutron signal

Cou

nts

Energy (ch)

Analysis procedure (Preliminary plots / ongoing)

First estimation of 210Po halflife of 150 ms. Compatible with literatur results

Analysis BELENIntroduction Experiment Analysis

DDAS- Triggerless digital data acquisition system used for the first time in thistype of experiments at GSI.

- It allows to eliminate the dead timeof conventional acquisition systemsthanks to the double memory digitalcards 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.

Tracking detectors calibrations & particle ID

Particle ID check via 205Bi isomers,216Po α-decays

SIMBA calibrationimplantation patterns

Analysis of half lives and Pn

Digital data acquisition system features

Analysis procedure (Preliminary plots / ongoing)

Analysis BELENIntroduction Experiment Analysis

Future analysis work

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.

Analysis BELENIntroduction Experiment Analysis

Design of the prototype of the BELEN detector with MCNPX and

GEANT4 simulations. Different versions:

Analysis Future goalsIntroduction Experiment BELEN

Tests and experiments with Beta dELayEd Neutron detector (BELEN)

Background measurements at GSI and Canfranc underground laboratory.

BELEN-20 (20atm) for JYFL. Experiments at JYFLTRAP (Finland).

Measurements of β delayed neutron emission of fission fragments (UPC,

IFIC, CIEMAT):

Nov 2009: 95Rb, 88Br, 94Rb, 138I. (cal. and nucl. Structure)

Jun 2010 : 95Rb, 88Br, 85As, 86As, 85Ge, 91Br, 137I.(decay heat and

testing models)

BELEN-30 (20 (20atm), 10 (10 atm)) for FRS-GSI. Two experiments at GSI with & SIMBA

September 2011, nuclei of astrophysical interest:

S323: 127Pd, 126Pd, 128Ag S410: 215Tl, 211Hg

Future goals for the UPC Beta dELayEd Neutron detector (BELEN)

Analysis Future goalsIntroduction Experiment BELEN

Initial plans were for 44 3He counters.

Now collaboration with GSI & JINR (Dubna)

Plans of new design with 90 counters

(detection efficiency ~70%)

40 count @ 10 atm UPC (refurbishment)

10 count @ 10 atm GSI

40 count @ 4 atm JINR

Combine with Advanced Implantation Detector Array (AIDA), Surrey, UK.

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 path @FAIR/DESPEC (>2018)

Measure Pxn

New experiment at JYFL (Finland) on 2013

New proposals for RIKEN RIB facility in Japan

COUNTERS FOR BEta deLayEd Neutron detector

The end!

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)

Thanks to A.Algora, Y.Litvinov and K.Smith for some slides

Tomorrow!

State of the art

FRDM + QRPA

K.-L. Kratz, (private communication)

r-proce

ss path

T1/2

Pn

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)