Experiment S410

Measurement of beta-delayed neutrons around the third r-process peak

The objective of this experiment was the measurement of both -decay half-lives and -delayed neutron emission probabilities of a number of nuclei near the third r-process peak. Assuming a 238U beam intensity of 2×109 ions per second we have estimated that the isotopes 213−216Tl, 213,214Hg, 208−211Au, 208,209Pt and 205,206Ir can be implanted in sufficient intensity for such studies at the final focal plane of the GSI fragment separator. This will allow, for the first time, the measurement of their -decay halflives and neutron emission branching ratios. The high primary beam energy of 1 GeV/u available at GSI will be crucial for such measurements, in order to avoid contaminations due to incompletely stripped charge states. The -delayed neutron emission probability of these isotopes is expected to be at least 5%, and their implantation rates between 1E−2 s−1 and 1E−1 s−1, which should enable their measurement using a high-efficiency neutron detector. The detection system will also include an state-of-the-art array of DSSSDs for the detection of both implanted ions and -decays. HPGe-detectors will be used for gamma-ray tagging and will help for a precise A/q-calibration by measuring isomers in the neighbouring nuclei.

Time table (current status)

Experiment Proposal

• proposalPnv8.pdf: Experiment Proposal submitted to GSI-PAC on March 14th, 2010

PAC Presentation

• AstroPnGSI.pdf: Proposal defense at GPAC

LISE++ Calculations

• Preliminary FRS Plan RunPlanS410v2.pdf

• Isotopes of interest, expected halflifes, neutron emission probabilities and rates info_s410.pdf

• Matrix of Expected Implantation Rates and Total Counting Statistics rates_s410.pdf

• CS File for Fragmentation:U_xsec_72-92.cs; CS File for Fission: 238U-1AGeV-12C-ABRABLA-fission.cs

Related Links

• Belen Neutron Detector Array
• S323 Experiment - MSU Group
• GSI FRS Training Course
• The FRS Setup
• Wiki FRS: previous Logbooks, FRS Detectors, etc
• GSI beam schedule

-- CesarDomingo - 29 Jun 2011