E. Tryggestad

Low-temperature measurement of the giant dipole resonance width

Abstract The width of the giant dipole resonance (GDR) built on excited states was determined from a measurement of γ -decays in coincidence with 17 O particles scattered inelastically from 120 Sn. The bombarding energy was 80xa0MeV/u. A width of 4±1xa0MeV, consistent with the width of the GDR built on the ground state, was found at a temperature T =1xa0MeV. This result is in disagreement with adiabatic thermal shape fluctuation calculations, indicating an overestimation of the influence of thermal shape fluctuations at low temperature.

Low-lying dipole strength in 20O

Abstract Two 1− levels at 5.35(10) and 6.85(5)xa0MeV were observed for the first time in 20O. The strong direct excitation and subsequent γ-ray decay of these states in virtual photon scattering at 100xa0MeV/nucleon, along with B(Eλ) predictions for 20O states in this energy region, established their dipole character. The extracted B(E1)↑ values of ≃0.062(16)xa0e 2 fm 2 and ≃0.035(9)xa0e 2 fm 2 for the 5.35 and 6.85xa0MeV states, respectively, are significantly larger than shell model calculations predict. Such large dipole strengths are not observed for low-lying 1− states in 18O, indicating a shift of dipole strength towards lower energies as one approaches the neutron drip-line.

Low-lying E 1 strength in 20 O

A system, method and processing unit for mobile station location determination. Mobile Assisted Handoff (MAHO) measurements are sent to the processing unit that also retrieves the corresponding transmitted signal strengths and electromagnetic field distribution functions for the relevant base stations. The location of the mobile station is then determined by minimising the following formula: F u2061 ( gamma , x , y ) = ∑ j = 1 m u2062 M u2061 ( P Rj - gamma . P Tj . G j u2061 ( x , y ) ) where m is the number of relevant base stations, M is an optimisation metric (such as (epsilonj)2 or |epsilonj|)PRj is received signal strength, PTj transmitted signal strength, gamma attenuation (e.g. in the mobile station), and Gj(x,y) the electromagnetic field distribution function.

Low-lying E1 strength in 20O

A system, method and processing unit for mobile station location determination. Mobile Assisted Handoff (MAHO) measurements are sent to the processing unit that also retrieves the corresponding transmitted signal strengths and electromagnetic field distribution functions for the relevant base stations. The location of the mobile station is then determined by minimising the following formula: F u2061 ( gamma , x , y ) = ∑ j = 1 m u2062 M u2061 ( P Rj - gamma . P Tj . G j u2061 ( x , y ) ) where m is the number of relevant base stations, M is an optimisation metric (such as (epsilonj)2 or |epsilonj|)PRj is received signal strength, PTj transmitted signal strength, gamma attenuation (e.g. in the mobile station), and Gj(x,y) the electromagnetic field distribution function.

Low lying E1 strength in O-20

A system, method and processing unit for mobile station location determination. Mobile Assisted Handoff (MAHO) measurements are sent to the processing unit that also retrieves the corresponding transmitted signal strengths and electromagnetic field distribution functions for the relevant base stations. The location of the mobile station is then determined by minimising the following formula: F u2061 ( gamma , x , y ) = ∑ j = 1 m u2062 M u2061 ( P Rj - gamma . P Tj . G j u2061 ( x , y ) ) where m is the number of relevant base stations, M is an optimisation metric (such as (epsilonj)2 or |epsilonj|)PRj is received signal strength, PTj transmitted signal strength, gamma attenuation (e.g. in the mobile station), and Gj(x,y) the electromagnetic field distribution function.

First Low Temperature Measurement Of The Giant Dipole Resonance Width In Sn

The width of the Giant Dipole Resonance in Sn was studied by means of inelastic scattering. This study allowed for the first measurement of the GDR width at a temperature of 1 MeV. The width was found to be 4±1 MeV, and is consistent with the ground state measurement. This result is in disagreement with adiabatic thermal shape fluctuation calculations, indicating an overestimation of the influence of thermal shape fluctuations at low temperature.

Low‐Lying Dipole Strength In 20O

The availability of fast radioactive beams offers the possibility for studies of E1‐strength in projectiles via Coulomb excitation. Theoretical calculations predict that a significant fraction of this strength is shifted towards lower excitation energies in neutron‐rich systems (e.g., [1]). At the NSCL, virtual photon scattering was used to probe the discrete structure of both 18O and 20O for levels in the region between 1 and 8 MeV. Two 1− levels at 5.35(10) and 6.85(5) MeV were observed for the first time in 20O [2]. The observed γ‐ray spectrum for 20O is, in fact, dominated by transitions resulting from E1 excitations to these states. The extracted B(E1) ↑ values of ∼0.062(16) e2fm2 and ∼0.035(9) e2fm2 for the 5.35 and 6.85 MeV levels, respectively, are larger than shell model calculations predict [3, 4]. Such large dipole strengths are not observed for low‐lying 1− states in 18O, indicating a shift of dipole strength towards lower energies as one approaches the neutron drip‐line.