TAMU SHE 2015 Slide 1

Opportunities to study the SHE production mechanism with

rare isotopes at the ReA3 facility

Zach Kohley

National Superconducting Cyclotron Laboratory

Department of Chemistry

Michigan State University, E. Lansing, MI

International Symposium Super Heavy Nuclei

Texas A&M University, College Station, TX

March 31-April 2, 2015

TAMU SHE 2015 Slide 2

Outline

• Intro – Fusion with RIBs

• ReA3 Facility @ NSCL

• What can we do NOW with RIBs?

• Coincident Fission Fragment Detector

• Summary

• AcknowledgementsNSCL

TAMU SHE 2015 Slide 3

Motivation

New n-rich superheavy isotopes

1. Access long lifetimes

2. Fill in the n-rich gaps

3. Extended studies of N=162

4. New mass measurements?

5. Understand how to approach

N=184?

TAMU SHE 2015 Slide 4

Motivation

Has always has been intriguing to consider

the use of n-rich RIBs for SHE synthesis….

What has been done, experimentally, so far?

TAMU SHE 2015 Slide 5

Fusion with RIBs

Light Nuclei:6,8He, 9,11Li, 10,11Be, 8B, 10,11,14,15C, 17F, 20O

- Enhancement/hindrance due to

halo and weakly bound nuclei

- Astrophysics

TAMU SHE 2015 Slide 6

Fusion with RIBs

Light Nuclei:6,8He, 9,11Li, 10,11Be, 8B, 10,11,14,15C, 17F, 20O

HRIBF: 132,128,126Sn + 58,56Ni132Sn + 40,48Ca132Sn + 96Zr132Sn + 100Mo134Te + 40Ca

- Extreme neutron excess

- Sub-barrier transfer couplings

- Hindrance with n-rich RIBs

TAMU SHE 2015 Slide 7

Fusion with RIBs

“Fast beams”38S + 181Ta, 208Pb (NSCL)29,31Al + 197Au (RIKEN)

Light Nuclei:6,8He, 9,11Li, 10,11Be, 8B, 10,11,14,15C, 17F, 20O

HRIBF: 132,128,126Sn + 58,56Ni132Sn + 40,48Ca132Sn + 96Zr 132Sn + 100Mo134Te + 40Ca

SHE relevant hot and cold

fusion reactions require

medium-mass RIBs.

TAMU SHE 2015 Slide 8

Motivation

Q: What has been done, experimentally, so far?

A: Not much… 3 RIB experiments under difficult conditions

Q:Why?

A: (Opinion) Very few facilities with medium-mass RIBs at

appropriate energies.

TAMU SHE 2015 Slide 9

Where can we study SHE synthesis with RIBs?

NSCL has been a “fast” fragmentation facility (RIBs @ 50-150 MeV/u)

We want those same RIBs at lower energies (from thermal to Coulomb barrier)

for studying nuclear reactions, structure, and astrophysics.

Facilities currently offer low-energy RIBs:

ISAC-TRIUMF, SPIRAL, HIE-ISOLDE, CARIBU-ARIES-ANL, …, HRIBF

ReA3 represents a new concept of stopping and re-accelerating fast

fragmentation beams.

Projectile Fragmentation

TAMU SHE 2015 Slide 10

ReA @ NSCL

ReA

experimental areaEBIT Charge Breeder

gas stopping area

1. Produce RIB at NSCL

2. Thermalize beam in gas stopper

3. Charge breed isotope

4. Re-accelerate

1

2

34

RIBs with stable beam characteristics

TAMU SHE 2015 Slide 11

ReA @ NSCL

NSCL PAC38 accepted proposals at ReA3

NSCL PAC39 reviewing new proposals for ReA3

Beams include 47-37K, 46-34Ar, 40-30S

• Technique provides any beam that can be produced by projectile fragmentation

• Chemistry independent (compared to ISOL)

• Short development time for new beams.

MeV

/u

TAMU SHE 2015 Slide 12

ReA @ NSCL – Beam Intensities

Current Facility: NSCL + ReA

104-105 pps near stability

Example: 39-41K stable, 37K 8e3 pps, 46K 5e4 pps, 47K 3e4 pps

Future Facility: FRIB + ReA

Fast beam rates

1e10 pps

1e12 pps

TAMU SHE 2015 Slide 13

Big Picture for ReA

Applicability of RIBs for SHE production:

- Will new SHEs be produced at NSCL/ReA3? No

- Will new SHEs be produced at FRIB/ReA? VERY unlikely

- Can new isotopes of SHE’s be produced at FRIB/ReA? Possibly

What can we do NOW at NSCL/ReA?Study SHE reaction mechanism using neutron- and proton-rich RIBs

TAMU SHE 2015 Slide 14

Coincident Fission Fragment Detector

• Experimental program to study PCN

and scap with RIBs at ReA3.

• 4 large area PPACs (30cm x 40cm)

• 2V method for fission fragment mass

• 30-45% coincidence efficiency

• Large angular coverage

• Versatile device for stable and radioactive beam experiments.

beam

Goals: Define the most promising experiments

at FRIB for production of new neutron-rich

isotopes of SHEs.

Understand how or if the fusion process is

modified with the use of neutron-rich RIBs.

MCP Silicon

monitors

PPACS

TAMU SHE 2015 Slide 15

Coincident Fission Fragment Detector

Status (aka when will this happen!):

• Device is completed – final tests of PPACs and MCPs with digital electronics (XIA pixie systems)

• Approved PAC38 experiment hopefully run in Fall 2015: 46K + 208Pb

TAMU SHE 2015 Slide 16

Experimental Devices

Active Target Time Projection Chamber

10Be+4He

W. Mittig, D. Bazin, W.G. Lynch

Collaborators: LBNL, LLNL, ND, WMU, SMU

• Low intensity experiments (~100 pps)

• 4p efficiency

• dE/dX, E, Br, range, 3-D tracking

•Active or stationary target

• Max intensity ~2-5 * 104 pps

• Prototype TPC successfully commissioned

•Applicable for fusion/fission/breakup studies.

Large volume 100 cm x φ60 cm 0.2 to 1 atm gas pressure

High granularity 10,000 pads, ~5 x 5 mm2

Bρ analysis Solenoid 2T

a

a

a

TAMU SHE 2015 Slide 17

Summary

• Expect to see exciting results from low-energy structure and

reactions research at ReA3!

• ReA3 presents unique opportunity to explore SHE relevant

reactions with neutron- and proton-rich RIBs.

• Coincident Fission Fragment Detector constructed

• Need to think towards future of SHE research at FRIB.

• ReA6 upgrade to higher energies

• Spectrometer – ISLA White Paper available

• Welcome ideas for RIB experiments, interest in fusion at ReA3…

TAMU SHE 2015 Slide 18

Acknowledgments

David Hinde

Nanda Dasgupta

Cedric Simenel

Elizabeth Williams

Kalee Hammerton (GS)

Aditya Wakhle (PD)

Krystin Stiefel (GS)

John Yurkon (Det. Lab)

Theoretical Support:

Sait Umar

Volker Oberacker

Walt Loveland