[en] The use of integrated PET/MRI systems in clinical applications can best benefit from understanding their technological advances and limitations. The currently available clinical PET/MRI systems have their own characteristics. Thorough analyses of existing technical data and evaluation of necessary performance metrics for quality assurances could be conducted to optimize application-specific PET/MRI protocols. This Symposium will focus on technical advances and limitations of clinical PET/MRI systems, and how this exciting imaging modality can be utilized in applications that can benefit from both PET and MRI. Learning Objectives: To understand the technological advances of clinical PET/MRI systems To correctly identify clinical applications that can benefit from PET/MRI To understand ongoing work to further improve the current PET/MRI technology Floris Jansen is a GE Healthcare employee

[en] The new type of charged particle detector described comprises a thin layer of plastic scintillator over a much thicker CsI(Tl) crystal, an optical guide, and a photomultiplier. Results obtained at Chalk River Laboratories for the identification of particles with Z = 1-6 from the ¹²C + ¹⁹⁷Au reaction are shown. 12 refs., 4 figs

[en] The multifragmentation of quasiprojectiles was studied in the reactions of a ²⁸Si beam with ¹¹²Sn and ¹²⁴Sn targets at projectile energies of 30 and 50 MeV/nucleon. The quasiprojectile observables were reconstructed using isotopically identified charged particles with Z_f≤5 detected at forward angles. The nucleon exchange between projectile and target was investigated using the isospin and the excitation energy of the reconstructed quasiprojectile. For events with total reconstructed charge equal to the charge of the beam (Z_tot=14), the influence of the beam energy and target isospin on the neutron transfer was studied in detail. Simulations were carried out employing a model of deep inelastic transfer, a statistical model of multifragmentation, and a software replica of the FAUST detector array. The concept of deep inelastic transfer provides a good description of the production of highly excited quasiprojectiles. The isospin and excitation energy of the quasiprojectile were described with good overall agreement. The fragment multiplicity, charge and isospin were reproduced satisfactorily. The range of contributing impact parameters was determined using a backtracing procedure

[en] The enhancement in the production of even-Z nuclei observed in nuclear fission has also been observed in fragments produced from heavy ion collisions. Beams of ⁴⁰Ar, ⁴⁰Cl, and ⁴⁰Ca at 25 MeV/nucleon were impinged on ⁵⁸Fe and ⁵⁸Ni targets. The resulting fragments were detected using the MSU 4π detector array, which had additional silicon detectors for better isotopic resolution. Comparison of the ratios of yields for each element showed enhancement of even-Z fragment production. The enhancement was more pronounced for reactions with a greater difference in the N/Z of the compound system. However, this effect was less for systems that were more neutron rich. The average N/Z for fragments also displayed an odd-even effect with a lower average N/Z for the even-Z fragments. This is related to the greater availability of neutron-poor isotopes for even-Z nuclei

[en] Peripheral reactions of ²⁸Si with ¹¹²Sn and ¹²⁴Sn at 30, 40, and 50 MeV/nucleon were used to elucidate the effect of the neutron content of the target on the process of projectile fragmentation. It is demonstrated that the fragments that result from these projectile fragmentation reactions can be divided into those which are the result of statistical emission of the quasiprojectile and those that are part of a direct component. The statistical part is independent of the target whereas the isotopic composition of fragments from the direct component is dependent on the neutron content of the target. copyright 1999 The American Physical Society

[en] We have created quasiprojectiles of varying isospin via peripheral reactions of ²⁸Si+¹¹²Sn and ¹²⁴Sn at 30 and 50 MeV/nucleon. The quasiprojectiles have been reconstructed from completely isotopically identified fragments. The difference in N/Z of the reconstructed quasiprojectiles allows the investigation of the disassembly as a function of the isospin of the fragmenting system. The isobaric yield ratio ³H/³He depends strongly on N/Z ratio of quasiprojectiles. The dependences of mean fragment multiplicity and mean N/Z ratio of the fragments on N/Z ratio of the quasiprojectile are different for light charged particles and intermediate mass fragments. Observation of a different N/Z ratio of light charged particles and intermediate mass fragments is consistent with an inhomogeneous distribution of isospin in the fragmenting system

[en] The INDRA multidetector has been used to study multifragmentation process in the central collisions for the Xe+Sn reaction at 50 MeV/nucleon. Most (76%) of the emitted charge products comes from an equilibrated source having 12.5 MeV/nucleon of excitation energy. Kinetic energy spectra for intermediate mass fragments indicate a simultaneous disintegration with a collective expansion of about 2 MeV/nucleon. No dependence of this collective energy is found respect to the charge of the fragment. (author)

[en] The mass-symmetric reactions ⁵⁸Fe,⁵⁸Ni+⁵⁸Fe,⁵⁸Ni were studied at a beam energy of E_beam=30 MeV/nucleon in order to investigate the isospin dependence of fragment emission. Ratios of inclusive yields of isotopic fragments from hydrogen through nitrogen were extracted as a function of laboratory angle. A moving source analysis of the data indicates that at laboratory angles around 40 degree the yield of intermediate mass fragments (IMF close-quote s) beyond Z=3 is predominantly from a midrapidity source. The angular dependence of the relative yields of isotopes beyond Z=3 indicates that the IMF close-quote s at more central angles originate from a source which is more neutron deficient than the source responsible for fragments emitted at forward angles. The charge distributions and kinetic energy spectra of the IMF close-quote s at various laboratory angles were well reproduced by calculations employing a quantum molecular-dynamics code followed by a statistical multifragmentation model for generating fragments. The calculations indicate that the measured IMF close-quote s originate mainly from a single source. The isotopic composition of the emitted fragments is, however, not reproduced by the same calculation. The measured isotopic and isobaric ratios indicate an emitting source that is more neutron rich in comparison to the source predicted by model calculations. copyright 1998 The American Physical Society

[en] Fragments from the breakup of 32 MeV/nucleon ²⁰Na, ²⁰Ne, and ²⁰F projectile nuclei were measured with isotopic resolution using the FAUST detector array. Complete reconstruction of the fragmenting source was performed on an event-by-event basis. Events analyzed in this study were restricted to those with a summed fragment charge equal to the beam in which all fragments were isotopically identified. The change in neutron content of the projectile could be inferred from the complete isotopic reconstruction of the quasiprojectile. The < N/Z> present in the fragmenting source is not equal to the N/Z of the initial beam; there has been a shift toward the valley of stability. Additionally, there is now a distribution in the N/Z of the fragmenting system. Multineutron transfer from the neutron-rich target was observed for proton-rich projectiles

[en] The partition of decay energy between the kinetic energy of reaction products and their Q-value of formation is obtained in a statistical derivation appropriate to highly excited nuclei, and is shown to be in a constant ratio. We measure the kinetic energy fraction, R ΣE_kin/(ΣE_kin + ΣQ₀), over a wide range of excitation energy for well-defined systems formed in the ³⁵C1+¹²C reaction at 35A MeV. Relationships between excitation energy, charged-particle multiplicity, and intermediate-mass-fragment multiplicity, observed in this work and in recent experiments by a number of other groups, follow from the derivation of the average kinetic energies and Q-values