Projectile Projectile Fragmentation at Fragmentation at the Fragment the Fragment Separator Separator Andreas Heinz Andreas Heinz Wright Nuclear Structure Wright Nuclear Structure Laboratory, Laboratory, Yale University Yale University for the for the CHARMS CHARMS Collaboration Collaboration Symposium on 30 Years of Projectile Fragmentation, ACS meeting, San Francisco, September 10-11, 2006
23
Embed
Projectile Fragmentation at the Fragment Separator Andreas Heinz Wright Nuclear Structure Laboratory, Yale University for the CHARMS Collaboration Symposium.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Projectile Projectile Fragmentation at Fragmentation at
the Fragment the Fragment SeparatorSeparator
Andreas HeinzAndreas HeinzWright Nuclear Structure Laboratory, Wright Nuclear Structure Laboratory,
Yale UniversityYale University
for the for the CHARMSCHARMS CollaborationCollaboration
Symposium on 30 Years of Projectile Fragmentation, ACS meeting, San Francisco, September 10-11, 2006
CHARMSCHARMSCCollaboration for ollaboration for HHigh-igh-AAccuracy Experiments on Nuclear ccuracy Experiments on Nuclear RReaction eaction
MMechanisms with Magnetic echanisms with Magnetic SSpectrometerspectrometersP. ArmbrusterP. Armbruster11, A. , A. BacquiasBacquias11, , L. GiotL. Giot11, V. Henzl, V. Henzl1,121,12, D. Henzlova, D. Henzlova1,121,12, A. Keli, A. Kelićć11, S. , S. LukićLukić11, , R. R.
PleskaPleskačč11, M.V. Ricciardi, M.V. Ricciardi11, , K.-H. SchmidtK.-H. Schmidt11, O. Yordanov, O. Yordanov11, J. Benlliure, J. Benlliure22, J. Pereira, J. Pereira2,122,12, E. Casarejos, E. Casarejos22, , M. FernandezM. Fernandez22, T. Kurtukian, T. Kurtukian22, C.-O. Bacri, C.-O. Bacri33, M. Bernas, M. Bernas33, L. Tassan-Got, L. Tassan-Got33, L. Audouin, L. Audouin33, C. St, C. Stééphanphan33, ,
A. BoudardA. Boudard44, S. Leray, S. Leray44, C. Volant, C. Volant44, C. Villagrasa, C. Villagrasa44, B. Fernandez, B. Fernandez44, J.-E. Ducret, J.-E. Ducret44, J. Ta, J. Taïïebeb55, C. , C. SchmittSchmitt66, B. Jurado, B. Jurado77, F. Reymund, F. Reymund88, P. Napolitani, P. Napolitani88, D. Boilley, D. Boilley88, A. Junghans, A. Junghans99, A. Wagner, A. Wagner99, A. , A.
KuglerKugler1010, V. Wagner, V. Wagner1010, A. Krasa, A. Krasa1010, A. Heinz, A. Heinz1111, P. Danielewicz, P. Danielewicz1212, L. Shi, L. Shi1212, T. Enqvist, T. Enqvist1313, K. , K. HelariuttaHelariutta1414, A. Ignatyuk, A. Ignatyuk1515, A. Botvina, A. Botvina1616
11GSI, Darmstadt, GermanyGSI, Darmstadt, Germany22Univ. Santiago de Compostela, Sant. de Compostela, SpainUniv. Santiago de Compostela, Sant. de Compostela, Spain
33IPN Orsay, Orsay, FranceIPN Orsay, Orsay, France44DAPNIA/SPhN, CEA Saclay, Gif sur Yvette, FranceDAPNIA/SPhN, CEA Saclay, Gif sur Yvette, France
55DEN/DMS2S/SERMA/LENR, CEA Saclay, Gif sur Yvette , FranceDEN/DMS2S/SERMA/LENR, CEA Saclay, Gif sur Yvette , France66IPNL, Universite Lyon, Groupe Materie Nucleaire 4, Villeurbanne, FranceIPNL, Universite Lyon, Groupe Materie Nucleaire 4, Villeurbanne, France
77CENBG, Bordeau-Gradignan, FranceCENBG, Bordeau-Gradignan, France88GANIL, Caen FranceGANIL, Caen France
99Forschungszentrum Rossendorf, Dresden, GermanyForschungszentrum Rossendorf, Dresden, Germany1010Nuclear Physics Institute, Rez, Czech RepublicNuclear Physics Institute, Rez, Czech Republic
1111Wright Nuclear Structure Laboratory, Yale University, New Haven, USAWright Nuclear Structure Laboratory, Yale University, New Haven, USA1212NSCL and Physics and Astronomy Department, Michigan State University, East Lansing, USANSCL and Physics and Astronomy Department, Michigan State University, East Lansing, USA
1313CUPP Project, Pyhasalmi, FinlandCUPP Project, Pyhasalmi, Finland1414Univeristy of Helsinki, Helsinki, FinlandUniveristy of Helsinki, Helsinki, Finland
1515IPPE Obninsk, RussiaIPPE Obninsk, Russia1616Institute for Nuclear Research, Russian Academy of Sciences, Moscow, RussiaInstitute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia
TopicsTopics
Basic researchBasic research:: Momentum dependence of the nuclear mean field (Talk of Momentum dependence of the nuclear mean field (Talk of
V. Henzl)V. Henzl) Thermal instabilities of nuclear matter (Talk of D. Thermal instabilities of nuclear matter (Talk of D.
Henzlova)Henzlova) Dissipation in Nuclear Matter Dissipation in Nuclear Matter Very asymmetric fissionVery asymmetric fission Structure effects in fission and fragmentationStructure effects in fission and fragmentation Nuclide production in fragmentation and fission (Talk of J. Nuclide production in fragmentation and fission (Talk of J.
Benlliure)Benlliure)
ApplicationsApplications:: Nuclear astrophysicsNuclear astrophysics Spin, alignment and polarisation in fragmentationSpin, alignment and polarisation in fragmentation Transmutation of nuclear wasteTransmutation of nuclear waste Nuclear safetyNuclear safety Production of secondary beams (RIA, FAIR)Production of secondary beams (RIA, FAIR)
The Heavy-Ion Synchrotron at The Heavy-Ion Synchrotron at GSIGSI
Beams from p to 238U Energies of 1-2 A GeV
The FRagment Separator FRSThe FRagment Separator FRS
Z / Z 200
A / A 400
()/ 5·10-4
M.V. Ricciardi, PhD thesis
238U+Ti at 1 A GeV
Two “natural” observables:
Momentum distributions
Cross sections
Projectile FragmentationProjectile FragmentationTwo different time scales for abrasion and ablation →
(at least) a two-step process!
Abrasion
Ablation
Abrasion of nucleons in a peripheral collision produces excited CN Abrasion of nucleons in a peripheral collision produces excited CN (prefragment).(prefragment). high <E*> high <E*> 27 MeV per abraded nucleon 27 MeV per abraded nucleon
De-excitation through particle evaporation (n,p,De-excitation through particle evaporation (n,p,) or fission) or fission (relatively) low angular momenta (relatively) low angular momenta (listen tomorrow to Z. Podolyak)(listen tomorrow to Z. Podolyak)
Two components can be distinguished:- Quasi-elastic scattering (p replaces n in 208Pb)- (1232) excitation (e.g. n 0 p + -)Probability for excitation and energy in the nuclear medium can be deduced.
Nucleon excitation in projectile fragmentation1H(208Pb,208Bi)x at 1 A GeV
2H(208Pb,208Bi)x at 1 A GeV
Velocity of 208Bi in the frame of the 208Pb projectile.
Measured Nuclide Production in Measured Nuclide Production in Fragmentation and In-flight FissionFragmentation and In-flight Fission
Excellent basis for model developmentData available at: http://www-w2k.gsi.de/charms/data.htm
For heavy projectile fission opens up as a decay channel → knowledge of the fission properties of unstable heavy nuclei is necessary
ExperimentExperiment
Charge distribution
Total Kinetic Energy (TKE) distribution
Two Reaction Two Reaction MechanismsMechanisms
Plastic: only nuclear-induced fission
Pb: nuclear and electromagnetic-induced fission
Nuclear: ZCN = Z1 + Z2
Electromagnetic: ZCN = Z1 + Z2
→ trigger for low excitation energies!
Experimental Information Experimental Information on Fission at low Eon Fission at low E**
E*-Bf < 10 MeV
E. Konecny et al., Proc. Third IAEA Symp. Phys. Chem. Fission Vol 2, 1974, p. 3
A lot of new data!
Transition from Symmetric Transition from Symmetric to Asymmetric Fissionto Asymmetric Fission
Data resulted in:
o improved models for yield calculations
o better understanding of low-energy fission: evolution of fission channels, influence of pairing, …
• achievable luminosity: 1025-1029 cm-2s-1 depending on ion species
- spectrometer setup at the interaction zone
- detection system for RI in the arcs of the NESR (see EXL)
ConclusionsConclusions A lot of progress in the understanding of projectile A lot of progress in the understanding of projectile
fragmentation.fragmentation. Heavy beams and high resolution spectrometers are Heavy beams and high resolution spectrometers are
excellent tools.excellent tools. Don’t forget the influence of nuclear structure and Don’t forget the influence of nuclear structure and
nucleonic exciations.nucleonic exciations. A wealth of new data from projectile fragmentation, A wealth of new data from projectile fragmentation,
spallation, in-flight fission and fission of secondary spallation, in-flight fission and fission of secondary beams allowed for the development of realistic beams allowed for the development of realistic models with predictive power.models with predictive power.
Applications in accelerator driven systems, nuclear Applications in accelerator driven systems, nuclear astrophysics, ...astrophysics, ...