scholarly journals Simulation study of energy resolution, position resolution and >π0-γ separation of a sampling electromagnetic calorimeter at high energies

2017 ◽  
Vol 12 (07) ◽  
pp. P07013-P07013 ◽  
Author(s):  
A. Roy ◽  
S. Jain ◽  
S. Banerjee ◽  
S. Bhattacharya ◽  
G. Majumder
Author(s):  
Richard Wigmans

The energy resolution, i.e. the precision with which the energy of a showering particle can be measured, is one of the most important characteristics of a calorimeter. This resolution is determined by fluctuations in the absorption and signal formation processes. In this chapter, the different types of fluctuations that may play a role are examined, and their relative practical importance is addressed. Sources of fluctuations include fluctuations in the number of signal quanta, sampling fluctuations, fluctuations in shower leakage, as well as a variety of instrumental effects. Since the energy dependence of the different types of fluctuations is not the same, different types of fluctuations may dominate the energy resolution at low and and at high energies. An important type of fluctuations is part of the non-compensation phenomena. It concerns fluctuations in the strength of the electromagnetic component of hadronic showers. The effects of these fluctuations, which typically dominate the energy resolution for hadron and jet detection, are examined in detail. In sampling calorimeters, one particular shower particle may sometimes have catastrophic effects on the calorimeter performance. Several examples of such cases are discussed.


In this chapter a comparison between various designs of micropattern detectors is given, describing their specific advantages and disadvantages, which finally determines the fields of their applications. It is shown that at low counting rates the maximum achievable gas gain is determined by the Raether limit, which is about 106-107 electrons, depending on the design. At high counting rates, the maximum achievable gain additionally drops due to the contribution of several other effects (e.g. avalanches overlapping in space and time). Typically, micropattern detectors have a position resolution of ~30 µm, energy resolution of ~ 20% FWHM for 6 keV X-rays, and a time resolutions of ~1 ns. Some advanced designs offer even better characteristics. The diversity of micropattern detectors makes them attractive for many applications. For example, in measurements requiring simultaneously excellent time and position resolutions, mutigap multistrip detectors can be used in high energy physics applications, and hole-type structures are advantageous for the detection of visible photons. In some commercial applications, where reliability and robustness are important, spark protected detectors with resistive electrodes could be useful.


1998 ◽  
Vol 188 ◽  
pp. 335-336
Author(s):  
N. Y. Yamasaki ◽  
T. Ohashi ◽  
K. Kikuchi ◽  
H. Miyazaki ◽  
E. Rokutanda ◽  
...  

STJs are promising X-ray detectors as high energy resolution spectrometers due to the small excitation energy to break the Cooper pairs to product detectable electrons. The expected energy resolution is about 5 eV for a 6 keV incident X-rays (see review by Kraus et al. and Esposito et al.). We have developed a large area (178 × 178μm2) Nb/Al/AlOX/Al/Nb STJs (Kurakado et al. 1993) and series-connected STJs with a position resolution of 35μm for α particles (Kurakado 1997) at Nippon Steel Corporation. As a focal plane detector in future X-ray missions, we are developing STJs whose targert characteristics are; an energy resolution of 20 eV at 6keV, an effective area of 1 cm2, and position resolution of 100μm.


2010 ◽  
Vol 25 (09) ◽  
pp. 1739-1760 ◽  
Author(s):  
LUCIANO MANDELLI

In this paper it is shown how a sampling electromagnetic calorimeter based on the liquid argon technique satisfies the very demanding requirements of an experiment at the LHC. Section 2 discusses, using a simplified model, the performance that can be achieved in terms of response time, energy resolution and transverse granularity. Section 3 describes how the calorimeters are realized in ATLAS, their segmentation and how from the readout pulses the energy deposited in the calorimeter is computed. The motivations of a presampler detector in front of the calorimeter are also discussed. Section 4 describes how the energy, position and direction of an electron and a photon are computed. Finally, Sec. 5 briefly illustrates the rejection power of the calorimeter against the hadrons and mentions how a Higgs boson signal in the γγ channel can already be detected with a luminosity of 10 fb-1.


2001 ◽  
Vol 89 (12) ◽  
pp. 8202-8213 ◽  
Author(s):  
F. P. Santos ◽  
T. H. V. T. Dias ◽  
P. J. B. M. Rachinhas ◽  
C. A. N. Conde ◽  
A. D. Stauffer

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