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Student Sessions 2025
No full textHello all! My name is Julia, I am an engineering physics student from Canada. My project has been to construct a prototype of a Beam Intensity Monitor for the Beam Instrumentation group. In this talk, I will discuss the challenges and methods that go into the construction and installation of the prototype, as well as the vacuum capability and motorization that makes this prototype unique.
Well, actually… My additional goal with this talk is to encourage you to take a second look at detectors and instrumentation. Beyond just seeing diagrams, we will look at the “behind the scenes” of experiments, using the construction of my Beam Intensity Monitor as an example
The CERN n_TOF NEAR station for astrophysics- and application-related neutron activation measurements
No full textA new experimental area, the NEAR station, has recently been built at the CERN n_TOF facility, at a short distance from the spallation target (3 m). The new area, characterized by a neutron beam of very high flux, has been designed with the purpose of performing activation measurements of interest for astrophysics and various applications. The beam is transported from the spallation target to the NEAR station through a hole in the shielding wall of the target, inside which a collimator is inserted. The new area is complemented with a -ray spectroscopy laboratory, the GEAR station, equipped with a high-efficiency HPGe detector, for the measurement of the activity resulting from irradiation of a sample in the NEAR station. The use of a moderator/filter assembly is envisaged, in order to produce a neutron beam with quasi-Maxwellian energy distribution, of different thermal energies, necessary for the determination of Maxwellian Averaged Cross Sections of astrophysical interest. A new fast-cycling activation technique is also being investigated for measurements of reactions leading to isotopes of very short half life.A new experimental area, the NEAR station, has recently been built at the CERN n TOF facility, at a short distance from the spallation target (1.5 m). The new area, characterized by a neutron beam of very high flux, has been designed with the purpose of performing activation measurements of interest for astrophysics and various applications. The beam is transported from the spallation target to the NEAR station through a hole in the shielding wall of the target, inside which a collimator is inserted. The new area is complemented with a γ-ray spectroscopy laboratory, the GEAR station, equipped with a high efficiency HPGe detector, for the measurement of the activity resulting from irradiation of a sample in the NEAR station. The use of a moderator/filter assembly is envisaged, in order to produce a neutron beam of Maxwellian shape at different thermal energies, necessary for the measurement of Maxwellian Averaged Cross Sections of astrophysical interest. A new fast-cycling activation technique is also being investigated, for measurements of reactions leading to isotopes of very short half life
Recent results from NA61/SHINE
No full textThe NA61/SHINE experiment at the CERN SPS is a multipurpose fixed-target spectrometer for charged and neutral hadron measurements. Its research program includes studies of strong interactions as well as reference measurements for neutrino and cosmic-ray physics. A significant advantage of NA61/SHINE over collider experiments is its extended coverage of phase space available for hadron production. This includes the nearly entire forward hemisphere for charged hadrons and additionally, a large part of the backward hemisphere for specific neutrals. This paper summarizes a selected set of new results, obtained by NA61/SHINE since the last SQM conference (Busan, 2022). Particular attention is devoted to (1) the first-ever direct measurement of open charm production in nucleus-nucleus collisions at SPS energies (2) the difference observed between charged and neutral meson production in Ar+Sc reactions, up to now not understood by existing models, and (3) the importance of baseline effects in the search for the critical point of strongly interacting matter.The NA61/SHINE experiment at the CERN SPS is a multipurpose fixed-target spectrometer for charged and neutral hadron measurements. Its research program includes studies of strong interactions as well as reference measurements for neutrino and cosmic-ray physics. A significant advantage of NA61/SHINE over collider experiments is its extended coverage of phase space available for hadron production. This includes the nearly entire forward hemisphere for charged hadrons and additionally, a large part of the backward hemisphere for specific neutrals. This paper summarizes a selected set of new results, obtained by NA61/SHINE since the last SQM conference (Busan, 2022). Particular attention is devoted to (1) the first-ever direct measurement of open charm production in nucleus-nucleus collisions at SPS energies (2) the difference observed between charged and neutral meson production in Ar+Sc reactions, up to now not understood by existing models, and (3) the importance of baseline effects in the search for the critical point of strongly interacting matter
Spatial correlations of charm and anticharm quarks at hadronisation
No full textHeavy-ion collisions offer a unique tool for studying the properties of strong interactions at high energy densities. An open question is how heavy quarks, such as charm and bottom, thermalise in the dense matter created by these collisions. Here, we show that the momentum correlations of charm and anticharm hadrons produced in central heavy-ion collisions can provide direct information on the spatial correlations of charm-anticharm quark pairs at hadronisation. This is possible under conditions where only a single charm-anticharm pair is created, as expected in central lead-lead collisions at CERN Super Proton Synchrotron (SPS) energies. We introduce a method to correct the measured joint momentum distribution for smearing effects caused by hadronisation, making the results directly sensitive to spatial correlations. Using simulated data, we demonstrate that even a sample of limited statistics can distinguish between different spatial correlation scenarios. These results offer a novel test of heavy-quark production and transport models and are achievable with current detector technologies and beam intensities.Heavy-ion collisions are a unique tool for studying properties of strong interactions at high energy densities. In particular, the momentum correlations of charm and bottom hadrons have been considered for testing heavy quark thermalisation in the dense matter produced by the collisions. In this respect, two effects have been considered: the decrease of the initial back-to-back correlations and the increase of correlations due to heavy-quark interactions with the collectively flowing medium. Here, we show that information on the spatial correlations of the charm-anticharm quarks at the hadronisation can be extracted by measuring the momentum correlation of charm and anticharm hadrons produced in central collisions of two heavy nuclei. This, however, requires collisions with a single charm-anticharm quark pair created - the condition likely to be fulfilled in central Pb+Pb collisions at the CERN SPS energies. We introduce a method to correct the measured joint distribution function for the smearing of the charm and anticharm hadron momenta caused by hadronisation. Then the results are directly sensitive to the spatial correlations at the hadronisation. Using an example of central Pb+Pb collisions at the CERN SPS energies, we demonstrate that even a limited statistics of charm-anticharm hadron pairs can distinguish between different spatial correlation functions of charm-anticharm quarks at hadronisation. The results on spatial charm-anticharm quark correlations will provide a unique test of different assumptions on heavy quark creation in space-time and transport in dense, strongly interacting matter. We show that the existing detector technology and beam intensities at the CERN SPS should allow us to conduct the needed experiments soon
Recent highlights and prospects on (n,) measurements at the CERN n_TOF facility
No full textNeutron capture cross-section measurements are fundamental in the study of the slow neutron capture (s-) process of nucleosynthesis and for the development of innovative nuclear technologies. One of the best suited methods to measure radiative neutron capture (n,γ) cross sections over the full stellar range of interest for all the applications is the time-of-flight (TOF) technique. Overcoming the current experimental limitations for TOF measurements, in particular on low mass unstable samples, requires the combination of facilities with high instantaneous flux, such as the CERN n_TOF facility, with detection systems with an enhanced detection sensitivity and high counting rate capabilities. This contribution presents a summary about the recent highlights in the field of (n,γ) measurements at n_TOF. The recent upgrades in the facility and in new detector concepts for (n,γ) measurements are described. Last, an overview is given on the existing limitations and prospects for TOF measurements involving unstable targets and the outlook for activation measurements at the brand new high-flux n_TOF-NEAR station.Neutron capture cross-section measurements are fundamental in the study of the slow neutron capture (s-) process of nucleosynthesis and for the development of innovative nuclear technologies. One of the best suited methods to measure radiative neutron capture (n,) cross sections over the full stellar range of interest for all the applications is the time-of-flight (TOF) technique. Overcoming the current experimental limitations for TOF measurements, in particular on low mass unstable samples, requires the combination of facilities with high instantaneous flux, such as the CERN n_TOF facility, with detection systems with an enhanced detection sensitivity and high counting rate capabilities. This contribution presents a summary about the recent highlights in the field of (n,) measurements at n_TOF. The recent upgrades in the facility and in new detector concepts for (n,\g) measurements are described. Last, an overview is given on the existing limitations and prospects for TOF measurements involving unstable targets and the outlook for activation measurements at the brand new high-flux n_TOF-NEAR station
Recent results on heavy flavours and quarkonia from ALICE
No full textHeavy-flavour hadrons, containing at least one charm or beauty quark, are excellent probes of the deconfined medium created in ultrarelativistic heavy-ion collisions, known as quark–gluon plasma. Results in smaller collision systems, such as proton–proton and p–Pb collisions, besides representing an important baseline for interpreting heavy-ion measurements, are crucial to test perturbative QCD calculations and hadronisation mechanisms in the absence of hot medium effects, as well as to search for commonalities with heavy-ion systems. Recently, measurements in proton–proton and p–Pb collisions have revealed unforeseen features with respect to the expectations based on previous results from e+e− and ep collisions, showing that fragmentation fractions of heavy quarks are not universal. In this contribution, an overview of the most recent ALICE heavy-flavour measurements, along with the comparison to available calculations, will be discussed.Heavy-flavour hadrons, containing at least one charm or beauty quark, are excellent probes of the deconfined medium created in ultra-relativistic heavy-ion collisions, known as quark-gluon plasma. Results in smaller collision systems, such as proton-proton and p-Pb collisions, besides representing an important baseline for interpreting heavy-ion measurements, are crucial to test perturbative QCD calculations and hadronisation mechanisms in the absence of hot medium effects, as well as to search for commonalities with heavy-ion systems. Recently, measurements in proton-proton and p-Pb collisions have revealed unforeseen features with respect to the expectations based on previous results from and ep collisions, showing that fragmentation fractions of heavy quarks are not universal. In this contribution, an overview of the most recent ALICE heavy-flavour measurements, along with the comparison to available calculations, will be discussed
Tracing Different Types of Local Economic Benefits of RIs: The Case Study of LHC
No full textCERN is operating the world’s largest particle accelerator complex in the world. The interconnection of versatile particle accelerators working with different particle beams at different intensities and energies continue to attract scientists and engineers from all over the world. The socio-economic effects generated by the presence of in the region are manifold. They include, but are not limited to consumer spending, real-estate investments and local business and services activities, investments in education, leisure activities and tourism, urban development and tax contributions. This chapter traces different local socio-economic effects of concentrating a large number of people around a research infrastructure
Efficient high performance computing with the ALICE Event Processing Nodes GPU-based farm
No full textDue to the increase of data volumes expected for the LHC Run 3 and Run 4, the ALICE Collaboration designed and deployed a new, energy efficient, computing model to run Online and Offline O data processing within a single software framework. The ALICE O Event Processing Nodes (EPN) project performs online data reconstruction using GPUs (Graphic Processing Units) instead of CPUs and applies an efficient, entropy-based, online data compression to cope with PbPb collision data at a 50 kHz hadronic interaction rate. Also, the O EPN farm infrastructure features an energy efficient, environmentally friendly, adiabatic cooling system which allows for operational and capital cost savings