High-resolution Calorimeter Research Articles

J054062 MEMSセンサを用いた高感度カロリメータの研究([J05406]マイクロ・ナノスケールの熱流体現象(6))

Cells and microorganisms always generate metabolic heat as long as they are alive. So, total biological activity can be measured through the observation of metabolic heat at non-invasive and non-destructive, which is referred as "Bio-calorimetry". With downsizing and improvement in sensitivity of Calorimeters, the bio-calorimetry is expected to contribute in the medical, pharmacy and biotechnology. To use the MEMS (Micro Electro Mechanical System) technology, a bio-calorimetry can be measured a small heat generation. Therefore, we intended to development of high sensitivity and high resolution calorimeter with the MEMS technology. In this study, the batch type calorimeter with MEMS thermopile sensor was made, and its performance and thermal monitoring of Yeast metabolism were tested. As a result, the calorimeter evaluated a sensitivity of 2.6 V/W, a thermal noise equivalent to 23nW.For the thermal monitoring of the Yeast, the metabolic heat generation over 20 nW level was measured. In addition, we reported a flow type calorimeter with MEMS thermopile sensor for studying a biological response to a chemical stuff.

Cerenkov emission as a positive tag of double beta decays in bolometric experiments

Active background reduction in high resolution calorimeters is a promising approach to achieve ultimate sensitivity in neutrinoless double beta decay experiments. We propose Cerenkov emission from beta rays in bolometric crystals as a viable alternative to scintillation. This novel approach could broaden the range of materials of interest for calorimetric searches of the double beta decay. We discuss the optical properties of TeO2 crystals, as a show case.

CMS Electromagnetic Trigger commissioning and first operation experiences

The CMS electromagnetic calorimeter (ECAL) is a high-resolution calorimeter made of 75848 lead tungstate crystals and optimized for the discovery of the Higgs boson in its two photon decay mode. In view of the high raw event rate at the Large Hadron Collider, the ECAL Trigger will play a major role. This paper reviews the strategy and the tests completed to ensure that the ECAL Trigger reaches the required specifications. The results from the commissioning and the first experiences with cosmic ray data are presented.

Fast and compact lead tungstate-based electromagnetic calorimeter for the PANDA detector at GSI

Experiments with a cooled antiproton beam at the future accelerator facility at the Gesellschaft fur Schwer Ionenforschung, Darmstadt, Germany, will be performed with the 4/spl pi/ detector proton antiproton at Darmstadt comprising a high-resolution, compact, and fast homogeneous electromagnetic calorimeter to detect photons between 10 MeV and 10 GeV energy inside a superconducting solenoid (2 T). PbWO/sub 4/ (PWO) crystals, readout with large size avalanche photodiodes, represent an envisaged detector concept. The first results of a new generation of significantly improved PWO crystals, operated at different temperatures, are presented and discussed in detail. The requirements for the photo sensor are outlined based on first test measurements. A new fast hybrid photomultiplier (PLANACON 85001-501, BURLE) with channel plate amplification was investigated for comparison.

Heavy ion physics with the CMS experiment at the LHC

The LHC will collide protons at √ s = 14.0 TeV and lead beams at √ SNN = 5.5 TeV as well as other AA and pA combinations. The physics program of the Compact Muon Solenoid (CMS) includes the study of heavy ion collisions. The collision energy, much higher than is available at RHIC, will allow the study the dense partonic system with very hard probes: heavy quarks and quarkonia with emphasis on the b and γ, W ± and Z 0 bosons, high p T jets, photons. The production of these particles is likely to be modified, relative to pp collisions, by the presence of the hot hadronic medium. The CMS detector consists of a 13 m long, 6 m diameter superconducting solenoid which provides a uniform 4T magnetic field. The silicon tracker and electromagnetic and hadronic calorimeters are located inside the magnet while the muon detector is outside. The high granularity, high resolution calorimeters will provide hermetic coverage for | η| ≤ 5.5, making CMS an ideal detector to study high p T nuclear phenomena.

Critical Heat Anomaly in Frustoelectric Liquid Crystals

Heat capacity of a liquid crystal which exhibits a frustoelectric phase has been measured by a high-resolution ac calorimeter. A significant heat capacity peak was observed at the transition. The excess heat capacity for this transition showed a non-Landau critical behavior. The transition was found to be weakly first-order. The data have been analyzed with a preasymptotic power-law equation which includes correction-to-scaling terms.

Search for the proton decay mode p→νK in Soudan 2

We have searched for the proton decay mode proton to neutrino K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0. We found one candidate event consistent with background, yielding a limit, tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.

CMS performance for CP violation measurements

Recent set of structure functions, branching ratios and the current understanding of detector performance lead to a new evaluation of the CP reach of CMS. Compared to previous analysis, expected numbers of fully reconstructed and μ tagged B events are smaller, but are partly recovered thanks to progress on low pT electron identification based upon the high-resolution and fine granular electromagnetic calorimeter. This allow to use electrons for tagging purpose as well as for J/ψ − e+e− reconstruction.

STUDIES OF SURFACE-INDUCED LAYER-BY-LAYER TWO-STAGE PHASE TRANSFORMATIONS

Utilizing our high-resolution ac calorimeter, optical reflectivity, and electron diffraction, we have found a few very interesting phenomena associated with the free-standing films of the N-(4-n-butyloxybenzylidene)-4-n-octylaniline (4O.8) compound. Upon cooling from the smectic-A phase, the outer surface layers display a distinct hexatic-B order and subsequently transforms into crystal-B phase through a two-stage transformation. Each stage is found to be first order. The film exhibits a layer-by-layer ordering transitions developed from the film/vapor interface inwardly.

Preasymptotic 3D XY Critical Behavior of Heat Capacity at Normal-Incommensurate Phase Transition in K2ZnCl4and K2SeO4

Heat capacity of K 2 ZnCl 4 and K 2 SeO 4 has been measured using a high-resolution ac calorimeter. Critical behavior of the heat capacity anomalies associated with the normal-incommensurate (N-INC) phase transitions has been analyzed with the preasymptotic renormalization-group expression which includes correction terms up to the second order. It is revealed that the heat capacity anomalies of K 2 ZnCl 4 and K 2 SeO 4 are described well with the three dimensional (3D) XY model; the critical exponent, the critical amplitude ratio and the dimensionless ratio derived from the first-order correction terms agree well with the theoretically expected values of 3D XY model. These results are consistent with our previous experimental result for Rb 2 ZnCl 4 and the Cowley and Bruce's prediction that the N-INC phase transition is classified into the 3D XY system.

Calibration and performance of the CHORUS calorimeter

A high resolution calorimeter has been built for CHORUS, an experiment which searches for ν μ → ν τ oscillation in the CERN neutrino beam. Aim of the calorimeter is to measure the energy and direction of hadronic showers produced in interactions of the neutrinos in a nuclear emulsion target and to track through-going muons. It is a longitudinally segmented sampling device made of lead and scintillating fibers or strips. This detector has been exposed to beams of pions and electrons of defined momentum for calibration. The method used for energy calibration and results on the calorimeter performance are reported.

Calibration and performance of the CHORUS calorimeter

A high resolution calorimeter has been built for CHORUS, an experiment which searches for ν μ → ν τ oscillation in the CERN neutrino beam. Aim of the calorimeter is to measure the energy and direction of hadronic showers produced in interactions of the neutrinos in a nuclear emulsion target and to track through-going muons. It is a longitudinally segmented sampling device made of lead and scintillating fibers or strips. This detector has been exposed to beams of pions and electrons of defined momentum for calibration. The method used for energy calibration and results on the calorimeter performance are reported.

The CHORUS calorimeter: test results

In the framework of the CHORUS experiment for the search of vμ ↔ vτ oscillations at CERN, we have built the high resolution calorimeter, intended for the measurement of the energy of hadronic showers produced in neutrino interactions. The calorimeter consists of three parts. The first two are made of lead and plastic scintillating fibers in the volume ratio 4 : 1, such as to achieve compensation. The third is a sandwich of lead plates and scintillator strips in the same volume ratio. The techniques used for the construction of the calorimeter are described, as well as its performance in shower and muon detection. We used electron, pion and muon beams in the energy range 2–100 GeV for this purpose.

FERMI: a digital Front End and Readout MIcrosystem for high resolution calorimetry

We present a digital solution for the front-end electronics of high resolution calorimeters at future colliders. It is based on analogue signal compression, high speed A D converters, a fully programmable pipeline and a digital signal processing (DSP) chain with local intelligence and system supervision. This digital solution is aimed at providing maximal front-end processing power by performing waveform analysis using DSP methods. For the system integration of the multichannel device a multi-chip, silicon-on-silicon multi-chip module (MCM) has been adopted. This solution allows a high level of integration of complex analogue and digital functions, with excellent flexibility in mixing technologies for the different functional blocks. This type of multichip integration provides a high degree of reliability and programmability at both the function and the system level, with the additional possibility of customising the microsystem to detector-specific requirements. For enhanced reliability in high radiation environments, fault tolerance strategies, i.e. redundancy, reconfigurability, majority voting and coding for error detection and correction, are integrated into the design.

Construction and test of modules of the CHORUS calorimeter

The CHORUS Collaboration is presently building a new detector for the search of ν μ - ν τ oscillations in the CERN neutrino beam, the experiment being sensitive to a mixing angle an order of magnitude smaller than the present limit. The basic components of the CHORUS “hybrid” detector are an active target made of nuclear emulsions, an air core spectrometer with scintillating fiber tracking, a high resolution calorimeter and a muon spectrometer. An account is given here of the design of the 110-tons compensating calorimeter, made of 1 mm diameter scintillating fibers embedded in a lead matrix, and of the test results from the first modules produced.

A new instrument for high statistics measurement of scintillating fibers

The large scale use of scintillating optical fibers in particle detectors is now starting, with the advent of lead-scintillating fiber calorimeters and their use in physics experiments. With respect to the use of scintillating fibers for the tracking of particle trajectories close to the interacting point, in this application we face very massive detectors and a very large quantity of scintillating fibers. On the other hand, their diameter does not need to be particularly small, as in the case of particle tracking when a good space resolution is required. The CHORUS Collaboration is presently building a new detector for the search of ν μ − ν τ oscillations on the CERN neutrino beam. A crucial task in the detector is ruled by the high energy resolution calorimeter. For its construction more than 400 000 scintillating plastic fibers have been used. Here we report on the characteristics and performance of a new instrument for high statistics measurement of the fiber properties in terms of light output and attenuation length of the light.

Optimization of Si-implanted thermistors for high resolution calorimeters to be used in a neutrino mass experiment

A procedure of optimization of Si-implanted thermistors was started, with the final aim to develop bolometers with a resolution of a few eV in the keV range. The initial approach was to assume that a thermal decoupling between phonons and hopping electrons establishes inside the thermistors, with consequent reduction of the sensitivity and incomplete transfer of the particle generated phonons to the conduction electrons. This assumption however failed in explaining the collected experimental data, which can be described much more satisfactorily introducing an electric field dependance of the thermistor resistance. This alternative interpretation modifies the parameter choice for an optimum device

High resolution crystal calorimetry at LHC

The search for Higgs bosons above Lep200 reach could be one of the main tasks of the future pp and ee colliders. In the intermediate mass region, and in particular in the range 80–140 GeV/ c 2, only the 2-photon decay mode of a Higgs boson produced inclusively or in association with a W boson gives a good chance of observation. A “dedicated” very high resolution calorimeter with photon angle reconstruction and pion identification capability should detect a Higgs signal with high probability. A crystal calorimeter can be considered as a conservative approach to such a detector, since a large design and operation experience already exists. The extensive R&D needed for finding a dense, fast and radiation hard crystal, is under way. Guide-lines for designing an optimum calorimeter for LHC are discussed and preliminary configurations are given.

Heat Capacity Investigations of Extremely Thin Liquid-Crystal Free-Standing Films

Abstract A high-resolution differential ac free-standing film calorimeter has been constructed in our laboratories. We have employed this unique calorimeter to investigate the evolution of the temperature dependence of heat-capacity anomalies through the smectic-A-hexatic-B-crystal-E transition sequence of one liquid crystal compound as the film thickness is reduced from a few hundred to just three molecular layers. The existence of free surfaces in the free-standing liquid-crystal films has a very strong effect on the development of the molecular order through the smectic-A-hexatic-B transition and other unexpected results related to the crystal-E order.

High-speed analog CMOS pipeline system

Abstract We present a switched-capacitor readout system for high speed analog signals. It consists of a 10 MHz four-channel delay-line chip with 58 samples per channel and a 12 channel buffer chip with a sampling rate of 1 MHz and a depth of nine samples. In addition the buffer chip includes an analog multiplexer with 25 inputs for the buffer channels and for 13 additional unbuffered signals. Both chips have been fabricated in CMOS-technology and will be used for the readout of the ZEUS high resolution calorimeter. The circuit and chip concept will be presented and some design optimizations will be discussed. Measurements from integrated prototypes will be given including some experimental data from irradiated chips.