_version_ 1866917063679803392
author Avoni, Giulio
Bruschi, Marco
Canale, Gianluca
Citron, Zvi
Cole, Brian
Dahle, Eitan
Dziedzic, Bartosz
Glik, Bar
Grosse-Perdekamp, Matthias
Guo, Yhan
Korcy, Krzysztof
Hoppesch, Matthew
Housenga, Mason
Lantz, Chad
Liu, Yi
Longo, Riccardo
Lund, Samantha
MacLean, Daniel
Meneghini, Stefano
Milovanovic, Marco
Mladenovic, Goran
Mohapatra, Soumya
Rafee, Farah Mohammed
Moyal, Yftach
Sbarra, Carla
Sbrizzi, Antonio
Seidlitz, Blair
Shenkar, Shir
Steinberg, Peter
Sudit, Lion
Valuch, Daniel
Young, Kristopher
author_facet Avoni, Giulio
Bruschi, Marco
Canale, Gianluca
Citron, Zvi
Cole, Brian
Dahle, Eitan
Dziedzic, Bartosz
Glik, Bar
Grosse-Perdekamp, Matthias
Guo, Yhan
Korcy, Krzysztof
Hoppesch, Matthew
Housenga, Mason
Lantz, Chad
Liu, Yi
Longo, Riccardo
Lund, Samantha
MacLean, Daniel
Meneghini, Stefano
Milovanovic, Marco
Mladenovic, Goran
Mohapatra, Soumya
Rafee, Farah Mohammed
Moyal, Yftach
Sbarra, Carla
Sbrizzi, Antonio
Seidlitz, Blair
Shenkar, Shir
Steinberg, Peter
Sudit, Lion
Valuch, Daniel
Young, Kristopher
contents Experimental studies of ultra-relativistic heavy ion collisions at the Large Hadron Collider (LHC) depend crucially on Zero Degree Calorimeters (ZDCs) that measure neutrons produced at near-beam rapidity in nucleus-nucleus collisions. In hadronic nuclear collisions these neutrons are mainly spectator neutrons, those that do not scatter from opposing nucleons during the collision. As a result, the ZDCs provide a vital probe of heavy ion collision geometry. The ZDCs are also essential in the study of ultra-peripheral collisions that are initiated by photons associated with the electric fields of one or both nuclei. Coherent photon emission typically leaves the photon emitter intact, making the observation of no ZDC signal, on one or both sides, a tag of such processes. The ATLAS ZDCs, built prior to Run 1 were substantially upgraded for LHC Run 3. The primary upgrades included replacement of the quartz Cherenkov radiator with $\text{H}_2$-doped fused silica rods; installation of fast air-core signal cables between the ZDC and the ATLAS USA15 cavern; new LED-based calibration system; and new electronics implemented for readout and fully-digital triggering. The ZDCs were also augmented with new "Reaction Plane Detectors" (RPDs) designed to measure the transverse centroid of multi-neutron showers to allow event-by-event reconstruction of the directed-flow plane in nuclear collisions. The Run~3 ZDC detectors, including the RPDs, are described in detail with emphasis on aspects that are new for Run~3.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05948
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Upgrades of the ATLAS Zero Degree Calorimeter System for Run 3 at the Large Hadron Collider
Avoni, Giulio
Bruschi, Marco
Canale, Gianluca
Citron, Zvi
Cole, Brian
Dahle, Eitan
Dziedzic, Bartosz
Glik, Bar
Grosse-Perdekamp, Matthias
Guo, Yhan
Korcy, Krzysztof
Hoppesch, Matthew
Housenga, Mason
Lantz, Chad
Liu, Yi
Longo, Riccardo
Lund, Samantha
MacLean, Daniel
Meneghini, Stefano
Milovanovic, Marco
Mladenovic, Goran
Mohapatra, Soumya
Rafee, Farah Mohammed
Moyal, Yftach
Sbarra, Carla
Sbrizzi, Antonio
Seidlitz, Blair
Shenkar, Shir
Steinberg, Peter
Sudit, Lion
Valuch, Daniel
Young, Kristopher
Instrumentation and Detectors
High Energy Physics - Experiment
Nuclear Experiment
Experimental studies of ultra-relativistic heavy ion collisions at the Large Hadron Collider (LHC) depend crucially on Zero Degree Calorimeters (ZDCs) that measure neutrons produced at near-beam rapidity in nucleus-nucleus collisions. In hadronic nuclear collisions these neutrons are mainly spectator neutrons, those that do not scatter from opposing nucleons during the collision. As a result, the ZDCs provide a vital probe of heavy ion collision geometry. The ZDCs are also essential in the study of ultra-peripheral collisions that are initiated by photons associated with the electric fields of one or both nuclei. Coherent photon emission typically leaves the photon emitter intact, making the observation of no ZDC signal, on one or both sides, a tag of such processes. The ATLAS ZDCs, built prior to Run 1 were substantially upgraded for LHC Run 3. The primary upgrades included replacement of the quartz Cherenkov radiator with $\text{H}_2$-doped fused silica rods; installation of fast air-core signal cables between the ZDC and the ATLAS USA15 cavern; new LED-based calibration system; and new electronics implemented for readout and fully-digital triggering. The ZDCs were also augmented with new "Reaction Plane Detectors" (RPDs) designed to measure the transverse centroid of multi-neutron showers to allow event-by-event reconstruction of the directed-flow plane in nuclear collisions. The Run~3 ZDC detectors, including the RPDs, are described in detail with emphasis on aspects that are new for Run~3.
title Upgrades of the ATLAS Zero Degree Calorimeter System for Run 3 at the Large Hadron Collider
topic Instrumentation and Detectors
High Energy Physics - Experiment
Nuclear Experiment
url https://arxiv.org/abs/2509.05948