arXiv subjects

Jonghan Park

Publications and source records attributed to Jonghan Park.

4 recordsLinked to original sources

arXiv2026

Development and demonstration of the Korea ALICE Telescope using electron beams at KEK PF-AR

The development of ultra-low-mass, high-precision vertex detectors is a key requirement for future collider experiments and motivates extensive research and development of novel silicon tracking technologies. In this work, we present the development and beam-test demonstration of the Korea ALICE Telescope (KATS), a silicon-tracking telescope designed to support R&D on next-generation cylindrical vertex detectors, such as the proposed ALICE ITS3 upgrade. The telescope consists of six ALPIDE Monolithic Active Pixel Sensors (MAPS) used as reference tracking planes, a bent ALPIDE sensor serving as the device under test, and a scintillating-fiber-based trigger system, all housed in a light-tight modular enclosure. This setup enables precise track reconstruction and detailed performance studies of both planar and curved silicon sensors. Beam tests were carried out using high-energy electron beams at the KEK Photon Factory Advanced Ring (PF-AR). The telescope system operated stably under realistic beam conditions, and its tracking performance was successfully validated. The bent ALPIDE sensor was operated at a bending radius of approximately 18 mm, consistent with ITS3's design goals, without any observable degradation in detection performance. The measured results confirm that the KATS provides a versatile and reliable platform for studies of curved MAPS technologies, alignment precision, and tracking performance. These results provide important experimental validation of key technologies for future low-mass cylindrical silicon vertex detectors and establish KATS as a valuable facility for ongoing and future detector R&D.

physics.ins-det↗

arXiv2024

Characterisation of analogue MAPS produced in the 65 nm TPSCo process

Within the context of the ALICE ITS3 collaboration, a set of MAPS small-scale test structures were developed using the 65 nm TPSCo CMOS imaging process with the upgrade of the ALICE inner tracking system as its primary focus. One such sensor, the Circuit Exploratoire 65 nm (CE-65), and its evolution the CE-65v2, were developed to explore charge collection properties for varying configurations including collection layer process (standard, blanket, modified with gap), pixel pitch (15, 18, \SI{22.5}{\micro\meter}), and pixel geometry (square vs hexagonal/staggered). In this work the characterisation of the CE-65v2 chip, based on $^{55}$Fe lab measurements and test beams at CERN SPS, is presented. Matrix gain uniformity up to the $\mathcal{O}$(5\%) level was demonstrated for all considered chip configurations. The CE-65v2 chip achieves a spatial resolution of under \SI{2}{\micro\meter} during beam tests. Process modifications allowing for faster charge collection and less charge sharing result in decreased spatial resolution, but a considerably wider range of operation, with both the \SI{15}{\micro\meter} and \SI{22.5}{\micro\meter} chips achieving over 99\% efficiency up to a $\sim$180 e$^{-}$ seed threshold. The results serve to validate the 65 nm TPSCo CMOS process, as well as to motivate design choices in future particle detection experiments.

physics.ins-det↗

arXiv2024

ALICE FoCal overview

The Forward Calorimeter (FoCal) is a new sub-detector in ALICE to be installed during the LHC Long Shutdown 3 for LHC Run 4. It consists of a highly-granular Si+W electromagnetic calorimeter combined with a conventional metal-scintillator hadronic calorimeter, covering a pseudorapidity interval of $3.2<η<5.8$. The FoCal is optimised to measure various physics quantities in the forward region, allowing exploration of the gluon density in hadronic matter down to $x\sim10^{-6}$, thus providing insights into non-linear QCD evolution at the LHC. These proceedings introduce the FoCal physics program and its corresponding performance. Additionally, the performance of the FoCal prototype will be presented.

hep-ex↗

arXiv2024

Recent heavy-flavour measurements from ALICE

Studying heavy-flavour mesons and baryons in hadronic collisions provides unique insights into the properties of heavy-quark hadronisation amid large partonic densities, where novel mechanisms beyond in-vacuum fragmentation may emerge. Examining heavy-flavour production across different collision systems and event multiplicities provides information about multi-parton interactions and the development of a strongly-interacting medium in high-multiplicity pp and p-Pb collisions. In Pb-Pb collisions, measurements of the nuclear modification factor ($R_{\rm AA}$) for charm and beauty hadrons provide a means to characterise the in-medium energy loss of heavy quarks in the quark-gluon plasma (QGP). In addition, measurements of the elliptic flow ($v_{2}$) for heavy quarks provide insights into their diffusion and their participation in the collective motion of the QGP. In this contribution, recent results of charm and beauty production measured with the ALICE detector are presented.

nucl-ex↗