SECAR

Overview

The Separator for Capture Reactions (SECAR) will be a recoil separator at NSCL and FRIB that is optimized for measurements of low-energy capture reactions of importance for nuclear astrophysics. Shown in the left image above, it will be installed in the ReA3 (low-energy reaccelerated beams) Hall (image above right) at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. Measurements with SECAR will focus on capture reactions needed to understand stellar explosions, including novae, X-ray bursts, supernovae, and other extreme astrophysical environments such as the interiors of very massive stars. SECAR is designed to have a performance that significantly exceeds that of all previous recoils separators used for astrophysics measurements. It is the flag ship experiment for the FRIB nuclear astrophysics community.

Approach

Reaccelerated proton-rich unstable beams will bombard an H or He gas target. The overwhelming majority of the beam particles will pass through the target with no interaction and will enter the SECAR separator system which is aligned along the beam axis. Approximately one projectile out of 10¹¹ to 10¹⁷ will undergo a capture reaction with a beam particle and form a capture-reaction recoil which enters the separator along with the intense background of unreacted projectiles. SECAR employs two velocity filters (crossed electric and magnetic field devices) to transport the recoils to a focal plane for detection while steering away the unreacted projectiles. A proof-of-principle study at Caltech in 1991 showed the viability of this approach with a stable beam. Subsequent measurements with other devices the DRAGON separator at TRIUMF ISAC and the Daresbury Recoil Separator (DRS) at ORNL HRIBF showed the capability to measure capture reaction recoils using radioactive beams. The SECAR design was developed by Georg Berg and Manoel Couder and is based on the same approach as the new St. George recoil separator at the University of Notre Dame -- with a significant expansion of a second velocity filter and overall larger size. The rejection of the SECAR separator with its focal plane detector is projected to be as high as 10¹⁷.

Collaboration

The SECAR collaboration currently includes nuclear astrophysics groups from Argonne National Lab, Central Michigan University, Colorado School of Mines, Louisiana State University, McMaster University, Michigan State University, University of Notre Dame, Oak Ridge National Lab, and South Dakota School of Mines. If you are interested in joining the SECAR collaboration, please contact Hendrik Schatz, schatz at nscl.msu.edu.

Collaboration Council

We have established a Collaboration Council to represent the broader SECAR collaboration within the SECAR Project.
The Council will
  - communicate needs of the collaboration to the Project
  - communicate project information to collaboration
  - foster growth of the collaboration
  - work to ensure SECAR addresses needs of the collaboration

Current Collaboration Council Members are: Michael Smith - ORNL (Chair); Dan Bardayan - Notre Dame; Alan Chen - McMaster Univ.; Catherine Deibel - LSU; Uwe Greife - Colorado School of Mines; Ernst Rehm - ANL; Frank Strieder - South Dakota School of Mines; and Chris Wrede - MSU.

Detailed Information

Please click on the following links for more detailed information on SECAR taken from the 2014 Pre-Conceptual Design Report:
• SECAR Overview
• SECAR Science
• SECAR Design

Status

After successful reviews in Summer 2014 (external experts), October 2014 (DOE-SC/NSF), and January 2015 (DOE-SC/NSF), the SECAR Project officially began on March 1, 2015. Project completion is anticipated in 2022, although the project is being managed to an early completion date in 2020.

Current activity

Specifications for the magnet system (magnets, velocity filters, and associated power supplies) have been written and put out for bid, and a number of bids received from vendors. We are currently (September 2015) evaluating the bids in preparation to select the vendor(s) for these major procurements by the end of September 2015.

Presentations

These two presentations give an overview of the SECAR Project and the science addressed by SECAR. They were given at the SECAR Collaboration Meeting on August 20, 2015. More information on this meeting, and a link to all of the presentations, can be found on our Meetings page.

Overview of SECAR Project, Hendrik Schatz (MSU)

SECAR Science, Michael Smith (ORNL)

A number of older presentations are given in the Archives page.