High-resolution Calorimeter Research Articles

Design and performance of a 10 MHz cmos analog pipeline

The development of an analog pipeline which will be used for the readout of the ZEUS high-resolution calorimeter is described. The pipeline will be built in CMOS-technology and will use the switched capacitor technique. Performance tests of a test chip which incorporates the main features of the pipeline are presented. The following results on the main parameters have been achieved: dynamic range about 8000:1, chargeup time better than 4 ns, timing accuracy better than 1 ns. First results on radiation sensitivity show that the chip operates properly up to 5 krad. On the basis of these results an improved design of a prototype chip has been started.

Development of the front end electronics for the ZEUS high resolution calorimeter

The development and design of the pipelined data acquisition system for the high-resolution ZEUS calorimeter are described. Details of the front-end analog card and its performance are presented. A description of the custom pipeline and buffer multiplexer chips is given, along with test results for the pipeline chip. In addition, some results are presented for a CCD (charge-coupled device) test system built to evaluate the pipeline principles using the ZEUS calorimeter prototype at the CERN PS.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Thermal Property Evolution Toward Effectively Two-Dimensional Substrate-Free Systems

ABSTRACTA high-resolution differential quasi-adiabatic calorimeter has been developed to investigate the physical properties of freestanding liquid-crystal films. Our recent heat-capacity studies near the smectic-A-hexatic-B transition of both 65OBC and 46OBC freestanding films clearly demonstrate the evolution towards twodimensional limiting behavior in four-layer films. As the film thickness decreases towards four molecular layers, the heatcapacity anomalies first display separate peaks for the surface and interior transitions and then evolve to one dominated by the surface transition.

Experimental study of uranium plastic scintillator calorimeters

As a preparation for the ZEUS high resolution calorimeter, sampling calorimeters made from 3.2 mm plates of depleted uranium read out by plastic scintillator of 3 mm and 5 mm thickness have been built. The response of hadrons, electrons and muons has been measured in the energy range between 3 and 100 GeV. In agreement with predictions, the relative response of electrons and hadrons as well as the hadronic energy resolution depend strongly on the thickness of the plastic scintillator. For 3.2 mm depleted uranium and 3 mm thick scintillator we observe over the full energy range equal response for electrons and hadrons; a hadronic energy resolution of 34.5% E[ GeV] is obtained. Results are given for the spatial resolution for electrons and hadrons. Finally, results from a lead scintillator calorimeter built as a prestudy before uranium plates were available are reported.

Thin-gap gas chambers for hadronic calorimetry

A new type of thin mutliwire gas detector operating in a high gain mode has been developed. Its characteristics have been optimized for calorimetric use. The setup for mass production, quality control and calibration for the OPAL Pole Tip Calorimeter Chambers is presented as an application of such a device. Other possible applications as an electromagnetic presampler as well as its use in a high resolution calorimeter are also discussed.

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 σ(E) E = 0.15 √E , and for hadrons σ(E) E = 0.35 √E , with a constant term of maximum 2% added in quadrature. First results from calorimeter test measurements are presented.

Thermal Detectors for High Resolution Spectroscopy

Thermal calorimeters operating in the millikelvin temperature range are capable of detecting single particle or photon interactions with deposited energy thresholds as low as a few electron volts. Small monolithic devices can be made using integrated circuit fabrication techniques and should have resolutions near 1 eV. Relatively crude test devices have already achieved resolutions for soft X-rays that are several times better than the best solid state detectors. It also may be possible to construct kilogram-scale detectors with thresholds less than 1000 eV. High resolution calorimeters have obvious applications in many types of spectroscopy, while the large-volume detectors would be useful for neutrino measurements and other rare interactions and decays. The truly unique characteristic of these large calorimeters as particle detectors is their sensitivity to non-ionizing interactions, and it has been proposed to use them to search for certain dark matter candidates and other exotic particles.

High resolution calorimeter for the investigation of melting in organic and biological materials

A high-resolution, high-sensitivity ac calorimeter has been developed to investigate the ''melting'' of organic and biological materials. The heart of this system is a simple yet very versatile sample cell which can be reused. High-temperature-resolution studies of the melting of n-octadecane and tert-butyl alcohol indicate interesting premelting and prefreezing phenomena in the specific heat capacity in these substances. With pure dipalmitoyl L-alpha-lecithin (DPL), in water, we obtain a very sharp (FWHM=0.38 degrees C) first-order phase transition showing no pretransition broadening or post-transition tails in the specific heat curves near the 41.2 degrees C transition point.

An Adiabatic Calorimeter for High-resolution Heat Capacity Measurements in the Temperature Range from 12 to 300 K

Abstract Construction of a high resolution calorimeter of an adiabatic type for single crystals is described. It uses a bank of thermistors for high resolution measurements in addition to a miniature platinum resistance thermometer. The results of heat-capacity measurements on benzoic acid as a standard material showed the inaccuracy of ±0.1% and the imprecision was confirmed to be less than ±0.05% between 50 and 275 K.