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To explain a difference of 0.5 % between the absorbed-dose standards of the National Institute of Standards and Technology (NIST) and the National Research Council of Canada (NRCC), Seuntjens et […]

A calorimeter is proposed for the measurement of meter-long high temperature superconducting power transmission cables' alternating current (AC) losses. The device is based on a temperature differential scheme and features 1 mW precision. It was designed for single, two-phase and three phase loss measurements. The calorimeter accurately measured coupling losses between phases.

The DELPHI Hadron Calorimeter was conceived more than ten years ago, as an instrument to measure the energy of hadrons and hadronic jets from [e.sup.+][e.sup.-] collisions at the CERN collider LEP. In addition it was expected to provide a certain degree of discrimination between pions and muons. The detector is a rather simple and relatively inexpensive device consisting of around 20,000 limited streamer plastic tubes, with inductive pad read-out, embedded in the iron yoke of the 1.2 T DELPHI magnet. Its depth is at minimum 6.6 nuclear interaction lengths. The electronics necessary for the pad readout was designed to have an adequate performance for a reasonable cost. This detector has proved over six years of operation to have an entirely satisfactory performance and great reliability; for example less than 1% of the streamer tubes have failed and electronic problems remain at the per mil level. During the past two years an improvement programme has been under way. It has been found possible to use the streamer tubes as strips, hence giving better granularity and particle tracking, by reading out the cathode of individual tubes. The constraints on this were considerable because of the inaccessibility of the detectors in the magnet yoke. However a cheap and feasible solution has been found. The cathode readout leads to an improved energy resolution, better [micron] identification, a better [Pi]/[micron] separation and to possibilities of neutral particle separation. The simultaneous anode read-out of several planes of the endcaps of the detector will provide a fast trigger in the forward/backward direction which is an important improvement for LEP200. On the barrel the system will provide a cosmic trigger which is very useful for calibration as counting rates at LEP200 will be very low.

The PHENIX Electromagnetic Calorimeter is a large 15,552 channel lead/scintillator sampling calorimeter based on the shish-kebab optical readout technique. In this report we summarize studies leading to an optimal design for measurement of photons and electrons in the 1 GeV momentum range within the high multiplicity environment expected for events at RHIC. Timing resolutions of [approximately]100 ps and a sampling dominated energy resolution of 8% at 1 GeV are featured. We also present a novel scheme for monitoring gain and timing of our entire system. Test results with a 144 channel preproduction 'super-module' exposed to electron and hadron beams at the AGS are described. The calorimeter is currently under construction in Russia and the US and will be fully installed at RHIC during 1998.

The DELPHI STIC detector is a lead-scintillator sampling calorimeter with wave length shifting optical fibers used for light collection. The main goal of the calorimeter at LEP100 is to measure the luminosity with an accuracy better than 0.1%. The detector has been in operation since the 1994 LEP run. Presented here is the performance measured during the 1994-1995 LEP runs, with the emphasis on the achieved energy and space resolution, the long-term stability and the efficiency of the detector. The new bunch-trains mode of LEP requires a rather sophisticated trigger and timing scheme which is also presented. To control the trigger efficiency and stability of the calorimeter channels, a LED-based monitoring system has been developed.

The performance of the High-density Projection Chamber (HPC), the barrel electromagnetic calorimeter of the DELPHI experiment, is described. The detector adopts the time projection technique in order to obtain exceptionally fine spatial granularity in the three coordinates ([similar to] 2 x 20 [mrad.sup.2] in [Theta] x [Phi] with nine samplings along the shower axes), using a limited number of readout channels (18,432). Among the various topics concerning the HPC construction and operation, major emphasis is given to the aspects related to the calibration in energy of the calorimeter, based mainly on the analysis of the detector response to 83mKr decays, and to the treatment of ageing in the readout proportional counters.

The endcap calorimeter of the CMD-2 detector for the VEPP-2M collider is described. The calorimeter contains 680 BGO crystals read out by vacuum phototriodes. Charge sensitive preamplifiers are placed directly on the phototriodes for the best noise performance. The calorimeter was installed during the last year. Calibration by cosmic rays showed the energy equivalent of the electronic noise to be about 0.9 MeV during operation in a 1 T magnetic field which corresponds to the design value.

To improve the identification and separation of leptons in the Hadron Calorimeter of DELPHI, one of the four LEP experiments at CERN, the possibility of a direct read-out of the cathodes of the 20,000 limited streamer tubes was studied and successfully tested on a small scale. A larger scale test started in June 1994. This new system which is independent of the present pad read-out provides a 'yes/no' information. The combination of both read-out systems makes it possible to use the Hadron Calorimeter as a track detector. The result of these tests show that the cathode read-out provides a better [Pi]/[Mu] separation, and improved detection of neutral long lived particles, enhanced discrimination of two showers and a more precise hadron energy measurement. It was decided to equip the whole detector with the new read-out, starting during the 94/95 shutdown.

The ZEUS calorimeter has now been operated for almost two years, collecting ep collision data at HERA. This uranium-scintillator calorimeter covers 99.8% of the solid angle and has an energy resolution of 35%/[square root of E] for hadrons and 17.5%/[square root of E] for electrons. It is intercalibrated at the level of 1% with the natural uranium radioactivity. It achieves better than 1 ns timing resolution for energy deposits greater than 4.5 GeV. It has an excellent noise performance with no coherent noise and a dynamic range equivalent to 16 bit. With the readout of its [approximately] 1200 channels, operated in pipelined fashion running at 10 MHz for 5 [[micro]seconds], and the trigger, it is a major piece of hardware which has to be kept operational and well calibrated. We review the detector as well as its readout and discuss the methods used for calibration and monitoring. The stability, the energy as well as the time calibration will be covered.

Several multitone harmonic-balance simulations are conducted to analyze the functions of an x-ray transition-edge sensor. The dynamic behaviour and applications of the sensor are also explained.

A new apparatus designed to eliminate the principal defect related to the substantial heat loss due to evaporation while using an open Styrofoam cup as a solution calorimeter is described. The heat loss in the apparatus is minimized by using a sealed calorimeter fitted with a magnetic stirrer and miniature bead thermistor that had a rapid response time of 6 s.