The activity of the 177Lu solution has been measured by means of the CIEMAT/NIST efficiency tracing method. This result has been compared to the previous obtained results received from 4πβ(LS)–γ ...coincidence and anticoincidence counting. The activities determined with various methods have been found to be consistent.
The decay curve of the 177Lu solution has been followed in the TDCR counter to determine the half-life of this isotope. The half-life has been separately determined for double and triple coincidence events. The arithmetic mean value of these two results has been found to be T1/2 = 6.6489(52) d.
•Activity standardization of 177Lu by means of the CIEMAT/NIST efficiency tracing method.•The activity result compared with previous results obtained from 4πβ(LS)–γ coincidence and anticoincidence counting.•The activities determined with various methods found to be consistent.•The half-life of 177Lu determined with small uncertainty.
A method for absolute measurements of the 225Ac activity in equilibrium with its progeny was developed. Measurements were performed using the triple-to-double coincidence ratio (TDCR) method in two ...different TDCR counters. The activity concentration of an 225Ac solution was determined and the solution was sent to the SIR system for a comparison. The half-life of 225Ac was determined by one of the TDCR counters and found to be 9.9150(63) days.
•Detailed determination of the counting efficiency of the 225Ac in radioactive equilibrium with its progeny.•Description of the measurements of the activity of 225Ac sources using the TDCR method.•Result of activity comparison in the International Reference System (SIR) at BIPM.•Results of half-life determination of 225Ac at POLATOM compared to other published values.
Nucleon knockout experiments using beryllium or carbon targets reveal a strong dependence of the quenching factors, i.e., the ratio (
R
s
) of theoretical to the experimental spectroscopic factors (
...C
2
S
), on the proton-neutron asymmetry in the nucleus under study. However, this dependence is greatly reduced when a hydrogen target is used. To understand this phenomenon, exclusive
1
H
(
17
Ne
,
2
p
16
F
)
and inclusive
12
C
(
17
Ne
,
2
p
16
F
)
X
,
12
C
(
17
Ne
,
16
F
)
X
as well as
1
H
(
17
Ne
,
16
F
)
X
(X-denotes undetected reaction products) reactions with
16
F
in the ground and excited states were analysed. The longitudinal momentum distribution of
16
F
and the correlations between the detached protons were studied. In the case of the carbon target, there is a significant deviation from the predictions of the eikonal model. The eikonal approximation was used to extract spectroscopic factor values
C
2
S
. The experimental
C
2
S
value obtained with C target is markedly lower than that for H target. This is interpreted as rescattering due to simultaneous nucleon knockout from both reaction partners,
17
Ne
and
12
C
.
New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation ...and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.
Hitherto three-body correlations between decay products of nuclear resonances, unstable to the emission of two neutrons have been a very effective tool in the analysis of GSI-experiments on ...super(5)H, super(10)He, super(13)Li, and super(14)Be. Here the first report is given about the mechanisms for two-proton emission from states in super(16)Ne, representing the presently most complete study of this nucleus. One-neutron knockout from super(17)Ne populated the super(16)Ne(g.s.) (E sub(r) = 1.39 MeV, Gamma = 0.08 MeV) above the super(14)O+p+p threshold, and resonances at E sub(r) = 3.22 MeV and 7.57 MeV. The decay mechanisms were revealed analysing three-body energy correlations in the super(14)O+p+p system. It was found that the super(16)Ne(g.s.) undergoes a democratic three-body decay.
.
The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20GeV/
c
protons impinging on a lead target. The facility, aiming primarily at the ...measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.
Neutron-rich super(34,35)Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the ...excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p sub(3/2) orbital favours super(34)Al(g.s)Hamiltonoperatorvp3/2 as ground state configuration of super(35)Al. But ground state configuration of super(34)Al is complicated as evident from gamma -ray spectra of super(33)Al after Coulomb breakup of super(34)Al.
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