13 research outputs found
The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers
The intrinsic time structure of hadronic showers influences the timing
capability and the required integration time of hadronic calorimeters in
particle physics experiments, and depends on the active medium and on the
absorber of the calorimeter. With the CALICE T3B experiment, a setup of 15
small plastic scintillator tiles read out with Silicon Photomultipliers, the
time structure of showers is measured on a statistical basis with high spatial
and temporal resolution in sampling calorimeters with tungsten and steel
absorbers. The results are compared to GEANT4 (version 9.4 patch 03)
simulations with different hadronic physics models. These comparisons
demonstrate the importance of using high precision treatment of low-energy
neutrons for tungsten absorbers, while an overall good agreement between data
and simulations for all considered models is observed for steel.Comment: 24 pages including author list, 9 figures, published in JINS
Performance of the first prototype of the CALICE scintillator strip electromagnetic calorimeter
A first prototype of a scintillator strip-based electromagnetic calorimeter
was built, consisting of 26 layers of tungsten absorber plates interleaved with
planes of 45x10x3 mm3 plastic scintillator strips. Data were collected using a
positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype's
performance is presented in terms of the linearity and resolution of the energy
measurement. These results represent an important milestone in the development
of highly granular calorimeters using scintillator strip technology. This
technology is being developed for a future linear collider experiment, aiming
at the precise measurement of jet energies using particle flow techniques
Effects of high-energy particle showers on the embedded front-end electronics of an electromagnetic calorimeter for a future lepton collider
Application Specific Integrated Circuits, ASICs, similar to those envisaged
for the readout electronics of the central calorimeters of detectors for a
future lepton collider have been exposed to high-energy electromagnetic
showers. A salient feature of these calorimeters is that the readout
electronics will be embedded into the calorimeter layers. In this article it is
shown that interactions of shower particles in the volume of the readout
electronics do not alter the noise pattern of the ASICs. No signal at or above
the MIP level has been observed during the exposure. The upper limit at the 95%
confidence level on the frequency of faked signals is smaller than 1x10^{-5}
for a noise threshold of about 60% of a MIP. For ASICs with similar design to
those which were tested, it can thus be largely excluded that the embedding of
the electronics into the calorimeter layers compromises the performance of the
calorimeters
Electromagnetic response of a highly granular hadronic calorimeter
The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the hadronic calorimeter, one option is a highly granular sampling calorimeter with steel as absorber and scintillator layers as active material. High granularity is obtained by segmenting the scintillator into small tiles individually read out via silicon photo-multipliers (SiPM). A prototype has been built, consisting of thirty-eight sensitive layers, segmented into about eight thousand channels. In 2007 the prototype was exposed to positrons and hadrons using the CERN SPS beam, covering a wide range of beam energies and incidence angles. The challenge of cell equalization and calibration of such a large number of channels is best validated using electromagnetic processes. The response of the prototype steel-scintillator calorimeter, including linearity and uniformity, to electrons is investigated and described
Hadronic energy resolution of a highly granular scintillator-steel hadron calorimeter using software compensation techniques
The energy resolution of a highly granular 1 m3 analogue scintillator-steel
hadronic calorimeter is studied using charged pions with energies from 10 GeV
to 80 GeV at the CERN SPS. The energy resolution for single hadrons is
determined to be approximately 58%/sqrt(E/GeV}. This resolution is improved to
approximately 45%/sqrt(E/GeV) with software compensation techniques. These
techniques take advantage of the event-by-event information about the
substructure of hadronic showers which is provided by the imaging capabilities
of the calorimeter. The energy reconstruction is improved either with
corrections based on the local energy density or by applying a single
correction factor to the event energy sum derived from a global measure of the
shower energy density. The application of the compensation algorithms to Geant4
simulations yield resolution improvements comparable to those observed for real
data.Comment: 26 pages, 14 figure
Track segments in hadronic showers in a highly granular scintillator-steel hadron calorimeter
We investigate the three dimensional substructure of hadronic showers in the CALICE scintillator-steel hadronic calorimeter. The high granularity of the detector is used to find track segments of minimum ionising particles within hadronic showers, providing sensitivity to the spatial structure and the details of secondary particle production in hadronic cascades. The multiplicity, length and angular distribution of identified track segments are compared to GEANT4 simulations with several different shower models. Track segments also provide the possibility for in-situ calibration of highly granular calorimeters
Construction and performance of a silicon photomultiplier/extruded scintillator tail-catcher and muon-tracker
A prototype module for an International Linear Collider (ILC) detector was
built, installed, and tested between 2006 and 2009 at CERN and Fermilab as part
of the CALICE test beam program, in order to study the possibilities of
extending energy sampling behind a hadronic calorimeter and to study the
possibilities of providing muon tracking. The "tail catcher/muon tracker"
(TCMT) is composed of 320 extruded scintillator strips (dimensions 1000 mm x 50
mm x 5 mm) packaged in 16 one-meter square planes interleaved between steel
plates. The scintillator strips were read out with wavelength shifting fibers
and silicon photomultipliers. The planes were arranged with alternating
horizontal and vertical strip orientations. Data were collected for muons and
pions in the energy range 6 GeV to 80 GeV. Utilizing data taken in 2006, this
paper describes the design and construction of the TCMT, performance
characteristics, and a beam-based evaluation of the ability of the TCMT to
improve hadronic energy resolution in a prototype ILC detector. For a typical
configuration of an ILC detector with a coil situated outside a calorimeter
system with a thickness of 5.5 nuclear interaction lengths, a TCMT would
improve relative energy resolution by 6-16 % for pions between 20 and 80 GeV.Comment: 23 pages, 18 figures, 4 tables, submitted to JINS
Tests of a particle flow algorithm with CALICE test beam data
The studies presented in this paper provide a first experimental test of the Particle Flow Algorithm (PFA) concept using data recorded in high granularity calorimeters. Pairs of overlaid pion showers from CALICE 2007 test beam data are reconstructed by the PandoraPFA program developed to implement PFA for a future lepton collider. Recovery of a neutral hadron's energy in the vicinity of a charged hadron is studied. The impact of the two overlapping hadron showers on energy resolution is investigated. The dependence of the confusion error on the distance between a 10 GeV neutral hadron and a charged pion is derived for pion energies of 10 and 30 GeV which are representative of a 100 GeV jet. The comparison of these test beam data results with Monte Carlo simulation is done for various hadron shower models within the GEANT4 framework. The results for simulated particles and for beam data are in good agreement thereby providing support for previous simulation studies of the power of Particle Flow Calorimetry at a future lepton collider
Shower development of particles with momenta from 1 to 10 GeV in the CALICE Scintillator-Tungsten HCAL
28 pages, 23 figures, 3 tablesLepton colliders are considered as options to complement and to extend the physics programme at the Large Hadron Collider. The Compact Linear Collider (CLIC) is an collider under development aiming at centre-of-mass energies of up to 3 TeV. For experiments at CLIC, a hadron sampling calorimeter with tungsten absorber is proposed. Such a calorimeter provides sufficient depth to contain high-energy showers, while allowing a compact size for the surrounding solenoid. A fine-grained calorimeter prototype with tungsten absorber plates and scintillator tiles read out by silicon photomultipliers was built and exposed to particle beams at CERN. Results obtained with electrons, pions and protons of momenta up to 10 GeV are presented in terms of energy resolution and shower shape studies. The results are compared with several GEANT4 simulation models in order to assess the reliability of the Monte Carlo predictions relevant for a future experiment at CLIC
Validation of GEANT4 Monte Carlo models with a highly granular scintillator-steel hadron calorimeter
Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8 GeV to 100 GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated