Misconceptions about Calorimetry

In the past 50 years, calorimeters have become the most important detectors in many particle physics experiments, especially experiments in colliding-beam accelerators at the energy frontier. In this paper, we describe and discuss a number of common misconceptions about these detectors, as well as the consequences of these misconceptions. We hope that it may serve as a useful source of information for young colleagues who want to familiarize themselves with these tricky instruments.Comment: Submitted to Instrument

On the limits of the hadronic energy resolution of calorimeters

In particle physics experiments, the quality of calorimetric particle detection is typically considerably worse for hadrons than for electromagnetic showers. In this paper, we investigate the root causes of this problem and evaluate two different methods that have been exploited to remedy this situation: compensation and dual readout. It turns out that the latter approach is more promising, as evidenced by experimental results.Comment: 21 pages, 12 figures, accepted for publication in Nuclear Instruments and Methods in Physics Research

Dual-Readout Calorimetry

In the past 20 years, dual-readout calorimetry has emerged as a technique for measuring the properties of high-energy hadrons and hadron jets that offers considerable advantages compared with the instruments that are currently used for this purpose in experiments at the high-energy frontier. In this paper, we review the status of this experimental technique and the challenges faced for its further development.Comment: 44 pages, 53 figures, accepted for publication in Review of Modern Physic

On Big Bang Relics, the Neutrino Mass and the Spectrum of Cosmic Rays

It is shown that high-energy features of the cosmic ray spectrum, in particular the kink around 4 PeV and the corresponding change in spectral index, may be explained from interactions between highly energetic cosmic protons and relic Big Bang antineutrinos, if the latter have a rest mass of about 0.4 eV/$c^2$. This explanation is supported by experimental data from extensive air-shower experiments, and in particular by the observation (Fly's Eye) of a second kink around 300 PeV, and by the abrupt change in the chemical composition of the cosmic ray spectrum that occurs at that energy. Both facts follow naturally from our theory, which predicts additional verifiable features of the cosmic ray spectrum in the few-PeV region, e.g. an abrupt decrease in the $p/\alpha$ ratio.Comment: 6 pages, 3 figures, Proceedings of the 6th Topical Seminar on Neutrino and Astroparticle Physics, San Miniato (Italy), 17-21 May 199

The Response of CMS Combined Calorimeters to Single Hadrons, Electrons and Muons

We report on the response of the combined CMS electromagnetic (EB) and hadronic barrel (HB) calorimeters to hadrons, electrons and muons in a wide momentum range from 1 to 350 GeV/c. To our knowledge, this is the widest range of momenta in which any calorimeter system is studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. We analyze in detail the differences in total calorimeter response to charged pions, kaons, protons and antiprotons and discuss the underlying phenomena. These data will play a crucial role in the thorough understanding of jets in CMS

Synchronization and Timing in CMS HCAL

The synchronization and timing of the hadron calorimeter (HCAL) for the Compact Muon Solenoid has been extensively studied with test beams at CERN during the period 2003-4, including runs with 40 MHz structured beam. The relative phases of the signals from different calorimeter segments are timed to 1 ns accuracy using a laser and equalized using programmable delay settings in the front-end electronics. The beam was used to verify the timing and to map out the entire range of pulse shapes over the 25 ns interval between beam crossings. These data were used to make detailed measurements of energy-dependent time slewing effects and to tune the electronics for optimal performance