The Short-Baseline Neutrino (SBN) physics program at Fermilab and Neutrino Platform (NP) at CERN are part of the international Neutrino Program leading to the development of Long-Baseline Neutrino ...Facility/Deep Underground Neutrino Experiment (LBNF/DUNE) science project. The SBN program consisting of three Liquid Argon Time Projection Chamber (LAr-TPC) detectors positioned along the Booster Neutrino Beam (BNB) at Fermilab includes an existing detector known as MicroBooNE (170-ton LAr-TPC) plus two new experiments known as SBN's Near Detector (SBND, ∼260 tons) and SBN's Far Detector (SBN-FD, ∼760 tons). All three detectors have distinctly different design of their cryostats thus defining specific requirements for the cryogenic systems. Fermilab has already built two new facilities to house SBND and SBN-FD detectors. The cryogenic systems for these detectors are in various stages of design and construction with CERN and Fermilab being responsible for delivery of specific sub-systems. This contribution presents specific design requirements and typical implementation solutions for each sub-system of the SBND and SBN-FD cryogenic systems.
The Rides Prerifaines (RP) of Morocco constitute the leading edge of the Rif chain. They involve a Triassic-Palaeocene succession deposited on a peneplained Palaeozoic fold belt and accumulated in ...basins delimited by NE-SW-trending normal fault systems. A significant hiatus separates an overlying Middle Miocene-Upper Miocene foredeep sequence. The reconstruction of the complex structural evolution of the RP during the later compressive phases that affected the Rif chain since Middle Miocene time has been the aim of this paper. We integrated field structural analyses, seismic line interpretation, and analogue modelling in order to evaluate the control exerted by the Late Triassic-Jurassic normal fault systems onto the later compressive tectonics. The maximum compression direction associated with the first compressive phase is roughly NE-SW to ENE-WSW oriented. During this phase the Mesozoic basin fill was scooped-out from the graben and the main décollement level were the Triassic evaporites. Since Pliocene times the maximum compression direction was oriented roughly N-S. During this phase the RP assumed their present structural setting. The earlier normal faults delimiting the Mesozoic graben were reactivated in a strike-slip mode also involving the Palaeozoic basement. The analogue modelling experiments demonstrated that the basement reactivation promoted salt tectonics and favoured fluid circulation.PUBLICATION ABSTRACT
Isomeric ratios have been measured for high-spin states in Po84198,200,206,208, At85208,209,210,211, Rn86210,211,212,213,214, Fr87208,211,212,213,214, Ra88210,211,212,214,215, and Ac89215 following ...the projectile fragmentation of a 1 A GeV 238U beam by a 9Be target at GSI Helmholtzzentrum für Schwerionenforschung. The fragments were separated in the fragment separator (FRS) and identified by means of energy loss and time-of-flight techniques. They were brought to rest at the centre of the RISING gamma-ray detector array and intensities of gamma rays emitted in the decay of isomeric states with half-lives between 100 ns and 40 μs and spin values up to 55/2 ℏ were used to obtain the corresponding isomeric ratios. The data are compared to theoretical isomeric ratios calculated in the framework of the abrasion–ablation model. Large experimental enhancements are obtained for high-spin isomers in comparison to expected values.
Fusion cross sections of 28Si + 28Si have been measured in a range above the barrier with a very small energy step (ΔElab=0.5 MeV). Regular oscillations have been observed, best evidenced in the ...first derivative of the energy-weighted excitation function. For the first time, quite different behaviors (the appearance of oscillations and the trend of sub-barrier cross sections) have been reproduced within the same theoretical frame, i.e., the coupled-channel model using the shallow M3Y + repulsion potential. The calculations suggest that channel couplings play an important role in the appearance of the oscillations, and that the simple relation between a peak in the derivative of the energy-weighted cross section and the height of a centrifugal barrier is lost, and so is the interpretation of the second derivative of the excitation function as a barrier distribution for this system, at energies above the Coulomb barrier.
Excitation functions of one- and two-neutron transfer channels have been measured for the closed shell 40Ca+96Zr and superfluid 60Ni+116Sn systems from the Coulomb barrier energy to energies far ...below. By using the unique PRISMA performance in terms of resolution and efficiency, measurements at very low bombarding energies have been performed. In the case of the 60Ni+116Sn system, a complementary particle-γ coincident measurements provide the ground and excited state populations. The experimental transfer probabilities have been compared with semiclasical microscopic calculations that incorporate nucleon-nucleon correlations, together with known structure information of entrance and exit channels nuclei and reaction dynamics. These calculations well reproduce, in the whole energy range, one- and two-neutron transfer channels in shape and magnitude.
.
Angular distributions of
γ
-rays for selected transitions in
40, 41, 42
Ar isotopes have been studied with the PRISMA magnetic spectrometer coupled to the CLARA
γ
array. These transitions were ...populated in Ar isotopes reached via neutron transfer in the
40
Ar +
208
Pb reaction. By comparison with the shape of the experimental angular distribution of the known E2 transitions we established more firmly the spin and parity of excited states. In particular, in
41
Ar for the
(
11
/
2
-
)
state through the
(
11
/
2
-
)
→
7
/
2
-
transition whose structure was discussed in terms of a phonon-fermion coupled state. The comparison with the expected fully aligned spin indicated that a high level of spin alignment has been reached.
•136Xe+198Pt shows a comparable contribution of proton pick-up and stripping.•Proton stripping channels in 136Xe+198Pt show enhanced cross sections.•Mass distributions of proton stripping channels in ...136Xe+198Pt shift to heavy side.
Multinucleon transfer reactions between two heavy ions are an important tool for production and investigation of exotic neutron-rich nuclei, which are difficult to access by other methods. The 136Xe+198Pt system is a candidate to efficiently produce neutron-rich nuclei around the neutron magic number N=126 for the KEK isotope separation project. In order to confirm this, measurements of the production cross sections with the large acceptance magnetic spectrometer VAMOS++ and de-excitation gamma rays from target-like fragments using the high efficiency germanium array EXOGAM at GANIL are reported. The measured isotopic distributions of the projectile-like fragments are compared with GRAZING calculations. The proton stripping channels show rough agreements between measurements and calculations. For the proton pick-up channels, the measured distributions are shifted toward the heavier masses and show enhanced cross sections in transfers of two or more protons.
Purpose: Cone beam CT (CBCT) has been widely used for patient setup in image guided radiation therapy (IGRT). The radiation dose from CBCT scans is a clinical concern. The purpose of this study is to ...quantitatively evaluate CBCT dose to brain cancer patients under IGRT using a GPU‐based Monte Carlo CBCT dose calculation package gCTD. Methods: We first performed dose measurements in a water phantom scanned under Varian OBI system and the measurement data are used to commission gCTD. Eight brain cancer patients under IGRT are studied. For each patient, dose distribution under a standard head scan protocol is computed, in which a 100 kVp x‐ray source rotates around the patient head in a 200‐degree range through the posterior side. Mean dose to key organs are computed. Mean dose to 2% voxels that have the highest dose is also computed to characterize dose inhomogeneity. Results: For each CBCT scan, dose to brain, brainstem, chiasm, eyes, and optical nerves ranges in 0.24–0.28cGy, 0.22–0.31cGy, 0.13–0.17cGy, 0.036–0.13cGy, and 0.061–0.17cGy, respectively, depending on the patient head size and isocenter position. The dose is not homogeneous and the mean doses to 2% voxels with the highest dose for these organs are 0.40‐0.58cGy, 0.30–0.43cGy, 0.18–1.02cGy, 0.063– 0.28cGy, and 0.093–0.83cGy, respectively. Although mean dose inside body is 0.26–0.41cGy, the maximum dose can be up to 3.3 cGy, which locates on the bone. It takes about 1 minutes on an Nvidia C2050 GPU card to simulate 1 billion source photons, yielding an average relative uncertainty less than 1%. Conclusion: For the standard head scan protocol, while average CBCT dose to each organ is relatively low, the dose distribution is not homogeneous and the maximum dose can be substantially high. gCTD provides an efficiency and accurate way to evaluate CBCT dose in IGRT.
We performed experiments to study the low-energy part of the E1 response (Pygmy Dipole Resonance) in 90,94Zr nuclei, by measuring the (p,p'γ) and (α,α'γ) inelastic scattering reactions at energies ...Ebeam,p = 80 MeV and Ebeam,α = 130 MeV respectively. The inelastically scattered particles were measured by employing the high-resolution spectrometer Grand Raiden. The gamma-rays emitted following the de-excitation of the Zr target nuclei were detected using both the clover type HPGe detectors of the CAGRA array and the large volume LaBr3:Ce scintillation detectors from the HECTOR+ array. Some preliminary results are presented here.
The experimental setup STELLA (STELlar LAboratory) is designed for the measurement of deep sub-barrier light heavy ion fusion cross sections. For background suppression the γ-particle coincidence ...technique is used. In this project, LaBr3 detectors from the UK FATIMA (FAst TIMing Array) collaboration are combined with annular silicon strip detectors customized at IPHC-CNRS, Strasbourg, and the setup is located at Andromède, IPN, Orsay. The commissioning of the experimental approach as well as a sub-barrier 12C +12C → 24Mg∗ cross section measurement campaign are carried out.