Measurement of associated charm production induced by 400 GeV/c protons

An important input for the interpretation of the measurements of the SHiP ex- periment is a good knowledge of the differential charm production cross section, including cascade production. This is a proposal to measure the associated charm production cross section, employing the SPS 400 GeV/c proton beam and a replica of the first two interaction lengths of the SHiP target. The detection of the produc- tion and decay of charmed hadron in the target will be performed through nuclear emulsion films, employed in an Emulsion Cloud Chamber target structure. In order to measure charge and momentum of decay daughters, we intend to build a mag- netic spectrometer using silicon pixel, scintillating fibre and drift tube detectors. A muon tagger will be built using RPCs. An optimization run is scheduled in 2018, while the full measurement will be performed after the second LHC Long Shutdown

Measurement of the muon flux from 400 GeV/c protons interacting in a thick molybdenum/tungsten target

The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About 1011 muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to (3.27±0.07) × 1011 protons on target was recorded. This amounts to approximatively 1% of a SHiP spill

Track reconstruction and matching between emulsion and silicon pixel detectors for the SHiP-charm experiment

In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beam-line. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87% is achieved

Hydrocracking of vacuum gas oil over NiMo/zeolite-Al2O3: Influence of zeolite properties

Hydrocracking of vacuum gas oil has been studied over NiMo/zeolite-Al2O3 catalysts. Three different zeolites have been used for catalysts preparation: zeolites Beta (BEA) and Y (FAU) having small crystal size and zeolite Y modified by recrystallization (RFAU). HRTEM, low-temperature N2 adsorption, FTIR of adsorbed CO and TPD-NH3 showed that zeolites had different crystal sizes, mesopore volume, strength and concentration of acid sites. Sulfide active component particles have been revealed to be similar in all catalysts by HRTEM and XPS. NiMo/BEA catalyst having zeolite with the smallest average particle size and the highest concentration of Brønsted acid sites (BAS) demonstrated the highest hydrocracking activity. Selectivity to middle distillates decreased in the following order: NiMo/FAU > NiMo/RFAU > NiMo/BEA. This effect is accounted for by optimal zeolite acidity and improved availability of the acid sites for bulky molecules of the heavy feedstock

Hydrocracking of vacuum gas oil over NiMo/zeolite-Al2O3: Influence of zeolite properties

Hydrocracking of vacuum gas oil has been studied over NiMo/zeolite-Al2O3 catalysts. Three different zeolites have been used for catalysts preparation: zeolites Beta (BEA) and Y (FAU) having small crystal size and zeolite Y modified by recrystallization (RFAU). HRTEM, low-temperature N2 adsorption, FTIR of adsorbed CO and TPD-NH3 showed that zeolites had different crystal sizes, mesopore volume, strength and concentration of acid sites. Sulfide active component particles have been revealed to be similar in all catalysts by HRTEM and XPS. NiMo/BEA catalyst having zeolite with the smallest average particle size and the highest concentration of Brønsted acid sites (BAS) demonstrated the highest hydrocracking activity. Selectivity to middle distillates decreased in the following order: NiMo/FAU > NiMo/RFAU > NiMo/BEA. This effect is accounted for by optimal zeolite acidity and improved availability of the acid sites for bulky molecules of the heavy feedstock