Escape suppressed spectrometer arrays: A revolution in γ-ray spectroscopy

Sharpey‐Schafer, J. F.; Simpson, John

doi:10.1016/0146-6410(88)90035-x

Cited by 71 publications

(14 citation statements)

References 150 publications

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“…The target consisted of 6 stacked lssW foils on thin carbon backings with combined thicknesses of 1.11mgcm -2 and 1.07mgcm -~ for the lower and higher beam energies respectively. Gamma-rays were detected using the TESSA3 array [3] which consists of 16 escape suppressed Ge spectrometers and a 50 element inner ball of bismuth germanate (BGO) detectors. The data comprised the energy deposited in each Ge detector and the sum-energy and fold recorded by the BGO ball for each event.…”

Section: Ig7-2~mentioning

confidence: 99%

Collective dipole rotational bands in197Pb

Clark

Wadsworth

Paul

et al. 1992

Z. Physik A - Hadrons and Nuclei

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The nucleus i97pb was populated via the is6w (17 0,6n) i97pb reaction at beam energies of 98 and 110 MeV. Two regular AI=I bands of magnetic dipole transitions have been found. Possible interpretations in terms of collective oblate configurations involving high-K proton orbitals coupled to three ii3/2 neutrons are discussed. The similarities between several of the bands discovered in ig7-2~nuclei are emphasized.Rotational oblate bands consisting of regular sequences of magnetic dipole transitions have recently been identified in 198,199,2~176 [1,2]. These structures have highly regular energy spacings of 45-55keV. Associated AI----2 electric quadrupole transitions are only weakly observed for some of the structures indicating that they have large B(M1)/B(E2) ratios (>10(,N/eb)2). The bands are all characterised by small moments of inertia (.~(2) typically varies between 20-30 h2MeV -i) with a rapid rise occurring at low frequency (hw <0.2 MeV). These structures have .been interpreted in terms of a high-K two proton configuration i 2 2 (e.g. (h9/2| or ( is/2)g=i2 or (hg/2)g=s) coupled to an aligned pair of ii3/2 neutrons in the even A nuclei, and to a single ii3/2 neutron in the case of i99pb [2]. In this short note we report the observation of two AI----1 bands in 197pb. Both bands display different characteristics from the structures previously discovered. They are, once again, very regular but have higher crossing frequencies (hw ~0.4 MeV) and for one of the structures the associated E2 transitions are much stronger. The reaction used to populate high spin states in 197pb was ls6w(i70,6n)iOTpb at beam energies of 98 and ll0MeV. The beam was provided by the 20MV tandem Van de Graft accelerator at the Daresbury Laboratory. The target consisted of 6 stacked lssW foils on thin carbon backings with combined thicknesses of 1.11mgcm -2 and 1.07mgcm -~ for the lower and higher beam energies respectively. Gamma-rays were detected using the TESSA3 array [3] which consists of 16 escape suppressed Ge spectrometers and a 50 element inner ball of bismuth germanate (BGO) detectors. The data comprised the energy deposited in each Ge detector and the sum-energy and fold recorded by the BGO ball for each event. A total of 100• events were recorded at 98MeV with 140• events at ll0MeV. The data were sorted into Exi-E~2 matrices with fold conditions that preferentially selected i9zpb.The analysis has resulted in the observation of two new col- figure). The intensities of band 1 and band 2 relative to the 1006 keV 7-ray (~+-~+) were measured to be 10% and 2.5% respectively. Looking at band 1, transitions in the known decay scheme are clearly seen in coincidence with it. The ~+ state at 1324 keV receives ~ 45% of the band intensity, whilst the ~-state at 1913 keV and the ~+ state at 1880 keV both receive ~ 20%. The ~+ state at 2652keV collects about 10%. Transitions from the ~ 2+ state at 3079keV, near the top of the known yrast sequence, are seen weakly (<2%). The band intensity indicates that the decay out of the band occu...

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Section: Ig7-2~mentioning

confidence: 99%

Collective dipole rotational bands in197Pb

Clark

Wadsworth

Paul

et al. 1992

Z. Physik A - Hadrons and Nuclei

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“…This assignment has been confirmed by a subsequent pulsed -beam measurement, using the same reaction, where the characteristic 7 rays following the 8-/3 decay were in intensity balance with the 3' -ray cascade built above the 8-isomer. In order to derive the level scheme at higher spin, an experiment was carried out at Daresbury using the ESSA30 array [3] of Compton -suppressed Ge detectors and the reaction 325 + 114Cd at I55 MeV. Doable, triple and higher multiplicity coincidence events were collected using both thin stacked targets (three foils, 500pg/cm 2 each) and a thick (1 /~g/cm 2) backed (15 mg/cm 2 Au) target.…”

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confidence: 99%

High-spin levels in the odd-odd nucleus142Eu

Bizzeti‐Sona

Bizzeti

Buonamici

et al. 1990

Z. Physik A - Atomic Nuclei

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“…The first experiment used a beam energy of 55 MeV on two selfsupporting 1 mg/cm foils of Er. The deexcitation y rays were detected in an array of five escape suppressed spectrometers [10].A total of 5X10 coincidence events were collected when two or more suppressed Ge detectors were in prompt (~100 ns) coincidence. Some of the results from this experiment have been reported previously [4].…”

Section: Highmentioning

confidence: 99%

Rotational structures inTa177

et al. 1995

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High-spin states in ' Ta were produced using the ' Er("B, 4n) reaction at 55 and 60 MeV. Considerable extensions have been made to the previously known level scheme, and new structures have been found. B(M1) B/(E2) ratios have been extracted for strongly coupled bands. The behavior of the different rotational cascades, in particular the anomalous crossing frequency observed in the [541]2 proton h9/2 band and the occurrence of "identical bands, " is discussed. Comparisons are made with projected shell model calculations.PACS number(s): 21.10. Re, 21.60.Cs, 23.20.Lv, 27.70.+q

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Escape suppressed spectrometer arrays: A revolution in γ-ray spectroscopy

Cited by 71 publications

References 150 publications

Collective dipole rotational bands in197Pb

Collective dipole rotational bands in197Pb

High-spin levels in the odd-odd nucleus142Eu

Rotational structures inTa177

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