- Spectroscopy of Proton-rich Nuclei in Explosive Nuclear Astrophysics
Spectroscopy of Super Heavy Nuclei
description
Transcript of Spectroscopy of Super Heavy Nuclei
Spectroscopy of
Super Heavy Nuclei
In-beam Studies
• Experience with gamma and CE studies• Unique set of problems• Main challenge is Fission
In-beam DataS. Eeckhaudt et al., EPJA 26, 226 (2005)
Equipment
• Target (Wheel)
• Prompt Spectrometer capable of high rate
• Separator with large transmission
• Excellent Recoil ID
• DAQ capable of high rate
Gamma Ray spectrometer
• Dominant channel is constant ~0.1 - 1b Fission. This limits Ge rate!
• Target wheel spokes need beam sweeping
• High granularity and large distance to keep individual rates low
• Background from entrance windows etc.– Need windowless system!
Rate calculation basics
• 10 pnA on 500 µg/cm2 at 1 µb = 325 Reactions/h
• At maximum XS ~20 ħ in the system• Fission rates adjusted to match
experimentally observed Ge rates, then scaled
• Two spectrometers: 10% and 50% Efficiency
e.g. EXOGAM or AGATA
Sample calculations
EXOGAM:500 2n 20 1000 650 64 5 10 194 1 500 90000 10 1.00 315 4.9 2.4 60
500 2n 20 100 65 64 5 10 19 11 500 90000 10 1.00 315 4.9 2.4 60
500 2n 20 10 7 64 5 10 2 107 500 90000 10 1.00 315 4.9 2.4 60
500 2n 200 10 65 64 5 10 19 11 500 900000 10 1.00 3147 49.2 24.0 60
AGATA:500 2n 50 100 163 192 5 50 168 1 500 225000 10 2.50 1969 10.3 15.0 60
500 2n 50 10 16.3 192 5 50 16.8 12 500 225000 10 2.50 1969 10.3 15.0 60
Compare Lines 3 and 4: Fission can become the bottleneck!
Bottlenecks
• Ge rate. Present: 10 kHz/detector
• With digital electronics and high throughput preamplifiers: 30 kHz/detector, eventual aim is 100 kHz/detector
• DAQ must handle these rates to preprocess and write to tape. Data rates up to 50MB/s– BGO suppression– Recoil coincidence
Conclusions
• Decay studies will be possible without large changes to existing detector technology and electronics. Target/Separator are crucial.
• In-beam studies will need highest rate capabilities – electronics, DAQ. Target must allow the beam, 10 nb level possible.
Marie-Helene Moscatello / M. Levitowicz (GANIL)Annamaria Porcellato (Legnaro)Uli Ratzinger (GSI)
Sigurd Hofmann (GSI)Rauno Julin (JYFL)Faisal Azaiez (IPN-Orsay)Giacomo DeAngelis (Legnaro)Rolf-Dietmar Herzberg (Liverpool)
Task: Produce a document to NUPECC
-Physics-Collaboration-Physics requirements (accelerator,target,instruments)
-Study the up-grade of existing or new accelerators to mach the physics requirements
ECOS: European COllaboration for Stable (ion beams)
--The Science with high intensity stable ion beams, Beam intensity limitations and technical developments for various types of research lines!
N=Z nuclei (in–beam spectroscopy and decay studies) : G. DeAngelisSHE search : S. HofmannSuper heavy nuclei (in-beam spectroscopy and decay studies) : R. D. HerzbergNeutron-deficient nuclei (in-beam spectroscopy and decay studies) : R. JulinExotic shapes and decay modes in nuclei : F. AzaiezNeutron rich nuclei using DIC reactions : F. Azaiez & G. DeAngelisNuclear astrophysics: S.V. Harissopulos
--Status and future developments of existing facilities
LEGNARO : A. PorcellatoGANIL : M. H. Moscatello/M. LewitoviczGSI : S. Hofmann&U. Ratzinger
JYVASKYLA : R. Julin KVI : S. Brandenburg
--Recommendations Draft (quasi-final):NuPECC web pages.