Study of Very Forward Neutrons with the CMS Zero Degree Calorimeter

Forward neutrons are studied in proton-lead collisions at the CMS experiment at the CERN LHC. They provide information on the centrality and event plane of collisions and provide an opportunity to study nuclear breakup. At the CMS experiment they are detected by the Zero Degree Calorimeters (ZDCs) in the | η | > 8.5 pseudorapidity range. The ZDCs are quartz fiber Cherenkov calorimeters using tungsten as absorber. Test beam data and events with a single spectator neutron are used for the calibration of these detectors. A Fourier-based method is used correct for the effect of multiple pPb collisions. The corrected ZDC energy distribution is used to calculate centrality percentiles and unfold the neutron multiplicity distribution.

New forward hadron calorimeter for centrality and reaction plane determination at BM@N heavy ion experiments

It is proposed to replace existing Zero Degree Calorimeter of the BM@N setup at the Nuclotron (JINR) by a new forward hadron calorimeter for the measurement of the collision centrality and reaction plane orientation in heavy ions experiments. This calorimeter with transverse and longitudinal segmentation will be assembled from modules presently constructed for FHCal MPD and PSD CBM. The proposed design of the new calorimeter, simulation results for centrality and reaction plane determination by the new calorimeter, as well as radiation doses in the calorimeter simulated by FLUKA are discussed. The performance of hadron calorimeter supermodule studied at CERN is shown.