Performance of uranium liquid argon calorimeters

We present results on the performance of a uranium liquid argon calorimeter exposed to electrons, pions and muons up to 150 GeV energy.     

Performance of the ATLAS electromagnetic calorimeter barrel module 0

The construction and performance of the barrel pre-series module 0 of the future ATLAS electromagnetic calorimeter at the LHC is described. The signal reconstruction and performance of ATLAS-like electronics has been studied. The signal to noise ratio for muons has been found to be 7.11±0.07. An energy resolution of better than (sampling term) has been obtained with electron beams of up to 245 GeV. The uniformity of the response to electrons in an area of Δη×Δφ=1.2×0.075 has been measured to be better than 0.8%.     

Response to muons,electrons and pions of a calorimeter constituted by small cross section brass tubes

A brass tube prototype calorimeter for the L3 detector has been exposed to the X3 beam of the CERN SPS. Its performance, tested with muons and electrons, is very satisfactory. With a sampling of 14 mm of copper, the energy resolution is 30% for 4 GeV pions.     

Experimental results from a sandwich calorimeter using U absorbers and 0.25 m of Si active area

The electromagnetic section of a hadronic calorimeter, consisting of uranium absorbers and of silicon sampling units with an active area of 0.25 m², was investigated. The overall performance of the silicon detectors and especially developed associated electronics, seems to be stable and reliable. During a four-week run at the t₉, CERN-PS (Proton Synchrotron) electron beam (energies of 2 to 6 GeV), no variation of energy calibration of the calorimeter was observed. The energy resolution for electromagnetic showers was found to be about , where E is the energy of the incoming electron and τ is the number of radiation lengths of passive material interspaced between two active samplers, for a calorimeter depth of 15.6 X₀ (radiation lengths), with Si samplers depleted to 200 μm. The fiberglass supports of the silicon mosaics cause a reduction of energy response to electromagnetic showers. It can be exploited to equalize the response of a Si/U hadronic calorimeter to incoming electrons and hadrons.     

The sat calorimeter of the DELPHI experiment at LEP; results of a module test

The construction of an electromagnetic calorimeter using scintillating plastic fibres and lead plates is described. The calorimeter is part of the Small Angle Tagger (SAT) of the DELPHI experiment at the LEP collider, recording high-energy electrons, positrons and photons. Results from a test of a module of similar construction are presented. The module was found to have a linear energy response when exposed to electrons of 10–70 GeV, with an energy resolution given by σ/E[%] = (1.16² + (11.4/√E[GeV])²)^1/2.     

Measurement of cascade showers in lead with thermoluminescent sheets

A new type of detector, thermoluminescent (TL) sheets (BaSO₄:Eu), and a readout system for the TL sheets have been developed to study electromagnetic cascade showers in ultrahigh energy interactions. To perform a measurement of showers recorded in TL sheets, the longitudinal and radial development of an electromagnetic cascade shower in lead produced by accelerator electrons has been studied for comparison. Simulations of the longitudinal and radial development of cascade showers were also performed using the EGS code system.

This study is useful for the design of a thermoluminescent calorimeter (TLC) for the measurement of electromagnetic cascade showers originating from ultrahigh energy (above 10¹⁵ eV) interactions.     

Beam test of the CsI(Tl) calorimeter for the BELLE detector at the KEK-B factory

We studied the performance of a prototype electromagnetic calorimeter for the BELLE detector at the KEK proton synchrotron for an energy range of 0.25–3.5 GeV. The prototype consisted of an array of 6 × 5 CsI(Tl) crystals with 30 cm length (16.2 radiation lengths) and about 6 cm × 6 cm cross section. The scintillation light of each CsI(Tl) crystal was read out by two large-area PIN photodiodes and charge-sensitive preamplifiers attached at the rear face of the crystal. We measured the energy and position resolution for electrons and the e/π separation for two sets of matrix configurations: one corresponded to the center and the other to the edge of the barrel calorimeter. The overall performance measured by the test proves that the prototype calorimeter is satisfactory for the use in the BELLE detector.     

The response of a streamer tube sampling calorimeter to electrons

We have constructed a simple modular electromagnetic calorimeter with 0.8X₀ copper absorbers using gas sampling with streamer tubes. To suppress saturation effects we use small cell streamer tubes (6 mm × 6 mm) filled with pure isobutane. The calorimeter has been tested with electrons in the energy range from 1 to 6 GeV. In this range the instrument shows a linear response. The energy resolution from pad and wire signals amounts to $\text{σ ≈}\text{20\%}\text{√E}$. The longitudinal shower profiles are in reasonable agreement with expectations from standard shower calculations.     

The CDF plug upgrade electromagnetic calorimeter: test beam results

The CDF Plug Upgrade calorimeter, which fully exploits the tile–fiber technique, was tested at the Fermilab meson beamline. The calorimeter was exposed to positron, positively charged pion and positive muon beams with energies in the range of 5–230 GeV. The energy resolution of the electromagnetic calorimeter to the positron beam is consistent with the design value of , where E is the energy in units of GeV and represents sum in quadrature. The non-linearity for positrons is studied in an energy range of 11–181 GeV. It is important to incorporate the response of the preshower detector, the first layer of the electromagnetic calorimeter which is readout separately, into that of the calorimeter to reduce the non-linearity to 1% or less. The energy scale is about 1.46 pC/GeV with HAMAMATSU R4125 operated typically at a gain of 2.5×10⁴. The response non-uniformity over the surface of a tower of the electromagnetic calorimeter is found to be about 2% with 57 GeV positrons. Studies of several detailed detector characteristics are also presented.     

GEANT4 physics evaluation with testbeam data of the ATLAS hadronic end-cap calorimeter

We evaluate the validity of the GEANT4 electromagnetic and hadronic physics models by comparing experimental data from beam tests of modules of the ATLAS hadronic end-cap calorimeter with GEANT4-based simulations. Two physics lists (LHEP and QGSP) for the simulation of hadronic showers are evaluated. Calorimeter performance parameters like the energy resolution and shapes of showers are studied both for electrons and charged pions. Furthermore, throughout the paper we compare GEANT4 and the corresponding predictions of GEANT3 used with the G-CALOR code for hadronic shower development.     

The ZEUS uranium-scintillator calorimeter for HERA

The high resolution calorimeter for the ZEUS detector at HERA is presented. The choice of a sandwich calorimeter from depleted uranium plates and plastic scintillator was made to accomplish compensation and thus the best possible energy resolution for hadrons and jets. The calorimeter is segmented transversely into towers and longitudinally into an electromagnetic and one or two hadronic sections. It is divided in a forward, barrel and rear part which surround hermetically the interaction region and the inner detectors. The expected energy resolutions are for electrons $\text{σ(E)}\text{E}\text{=}\text{0.15}\text{√E}$, and for hadrons $\text{σ(E)}\text{E}\text{=}\text{0.35}\text{√E}$, with a constant term of maximum 2% added in quadrature. First results from calorimeter test measurements are presented.     

Dose from slow negative muons

Conversion coefficients from fluence to ambient dose equivalent, from fluence to maximum dose equivalent and quality factors for slow negative muons are examined in detail. Negative muons, when stopped, produce energetic photons, electrons and a variety of high-LET particles. Contribution from each particle type to the dose equivalent is calculated. The results show that for the high-LET particles the details of energy spectra and decay yields are important for accurate dose estimates. For slow negative muons the ambient dose equivalent does not always yield a conservative estimate for the protection quantities. Especially, the skin equivalent dose is strongly underestimated if the radiation-weighting factor of unity for slow muons is used. Comparisons to earlier studies are presented.     

A highly segmented NaI(Tl) detector with vacuum photodiode readout for measuring electromagnetic showers at the CERN ISR

In this report we describe construction and performance of two identical units of electromagnetic shower counters which were installed in the axial-field spectrometer at the CERN-ISR in 1982 to provide improved detection of photons and electrons over a 1.3 sr solid angle of the AFS calorimeter. Thallium doped sodium-iodide in the form of small blocks served as an active shower material. Vacuum photodiodes and low-noise charge sensitive electronics were used for the deposited energy measurement and signal amplification. The stable performance of the detectors over a period of more than 18 months until the closure of the ISR has proven that vacuum photodiodes can reliably be utilized in highly modularized large scale detectors operating in a high magnetic field environment.     

A simple model of hadron calorimeters

A simple model of hadron calorimeter response is examined. It is found that not only must a hadron calorimeter be compensated in order to achieve linearity, but also that the intrinsic hadron and electromagnetic resolutions must be equal if the calorimeter resolution is to be independent of energy and have a Gaussian distribution.     

Test beam of a quartz-fibre calorimeter prototype with a passive front section

We present test-beam data analysis of a quartzfibre calorimeter prototype composed of a single active section with a passive absorber in front of it. The partial suppression of the electromagnetic showers leads to the equalization of the response to electrons and pions for a given depth of this passive section. Results are compared with the Monte-Carlo expectations.     

Possibility of increasing proton rejection by detecting primary cosmic radiation electrons using an ionization-neutron calorimeter

Measurements were made of the neutron yields from a lead absorber 60 cm thick in electromagnetic cascades initiated by 200–600 MeV electrons. A comparison between the neutron yields obtained for electrons and the results of similar measurements for protons and pions suggests that the rejection factor of the proton background is increased ∼10² times when an ionization-neutron calorimeter is used to measure primary cosmic radiation electrons at energies above 100 GeV. Pis’ma Zh. Tekh. Fiz. 24, 66–73 (September 26, 1998)     

Calorimeter tests with liquid ionization chambers

Configurations of sampling calorimeters with iron, lead and uranium as absorbers have been investigated using liquid ionization chambers as active elements. As liquid tetramethylsilane has been used. Results of beam tests with electrons, pions and muons in the energy range of 2 to 6 GeV are presented and compared with Monte Carlo simulations. In particular the questions regarding which configuration can compensate and the separation of sampling from intrinsic fluctuations have been studied.     

The CUSB-II detector

The properties and design philosophy of the first bismuth germanate electromagnetic calorimeter used in high energy physics are discussed. Presented also the first results on the energy resolution obtainable under different background conditions.     

Shower shape analysis and longitudinal sampled electromagnetic calorimeters

Possibilities to improve high energy electromagnetic calorimetry by means of suitable calorimeter segmentation are discussed. Some resulting improvements are examined concerning spatial resolution, photon-π⁰ separation, electron-hadron separation and energy resolution as far as dominated by rear leakage. One way to realize such a calorimeter is discussed by a specific example.     

An electromagnetic calorimeter with wavelength shifting fiber readout

We investigate the response of an electromagnetic calorimeter using wavelength shifting fibers for the readout. The calorimeter is a sandwich of lead and scintillator plates and the fibers are inserted into holes perpendicular to the plates. We study in particular light yield, uniformity of response and energy resolution. We also present a Monte Carlo interpretation of our experimental results.