Low momentum particle detector for the NA61 experiment at CERN

Abstract

The NA61 Experiment at CERN SPS is a large acceptance hadron spectrometer, aimed to studying of hadronhadron, hadron-nucleus, and nucleus-nucleus interactions in a fixed target environment. The present paper discusses the construction and performance of the Low Momentum Particle Detector (LMPD), a small time projection chamber unit which has been added to the NA61 setup in 2012. The LMPD considerably extends the detector acceptance towards the backward region, surrounding the target in hadron-nucleus interactions. The LMPD features simultaneous range and ionization measurements, which allows for particle identification and momentum measurement in the 0.1 -0.25 GeV/c momentum range for protons. The possibility of Z=1 particle identification in this range is directly demonstrated.

Results from pion-carbon interactions measured by NA61/SHINE for better understanding of extensive air showers

“…The centrality of nucleusnucleus collisions can be estimated using the measurement of the energy of projectile spectators with a calorimeter [5] located behind the time of flight detectors. For nucleon-nucleus collisions, the centrality is determined by counting low momentum particles from the target (so called 'gray protons') with a small TPC around the target [6].…”

The forward TPC system of the NA61/SHINE experiment at CERN: a tandem TPC concept

“…The FTPCs were constructed at two different facilities in two logical parts: the field cage and gas volume, and the amplification and readout wire plane. The design concept of the field cage and gas volume was largely motivated by an earlier small volume TPC chamber, called the LMPD [6]. The actual real scale design and prototyping was done at the University of Colorado Boulder in the U.S.A., and the assembly was done at CERN in Switzerland/France, due to the problems of transportation of a fragile pre-assembled field cage.…”

Recent hadron production measurements performed by the NA61/SHINE collaboration

“…The centrality of nucleus-nucleus collisions can be estimated using the measurement of the energy of projectile spectators with a calorimeter [5] located behind the time of flight detectors. For nucleon-nucleus collisions, the centrality is determined by counting low momentum particles from the target (so called 'gray protons') with a small TPC around the target [6]. a http://shine.web.cern.ch/content/author-list 1 SHINE = SPS Heavy Ion and Neutrino Experiment.…”