Radiation damage effects on calorimeter compensation

An important consideration in the design of a detector that is to be used at the Superconducting Super Collider (SSC) is the response of the calorimeter to electromagnetic and hadronic particles and the equality of those responses for different types of particles at equal incident energies, i.e. compensation. However, as the simulations that are reported show, the compensation characteristics of a calorimeter can be seriously compromised over a relatively short period of time due to the large radiation levels that are expected in the SSC environment. 6 refs., 3 figs

MICAP: A program for low energy neutron, ion and gamma-ray transport and one of its applications in calorimeter design

A new code system, MICAP, has been developed for the transport and production of low-energy (<20 MeV) neutrons, photons, and light and heavy ions. The results generated by this code system compare favorably with a wide variety of experimental data. Because of this success, MICAP can be used as a valuable tool in helping to analyze calorimeter systems. In particular, MICAP is used in this paper to determine the practicality of hydrogen knock-in as a method of achieving compensation in a uranium/silicon calorimeter, i.e., e/h = 1. The results indicate that compensation is probably possible but shower fluctuations may be increased. 22 refs., 3 figs., 5 tabs

Systematic effects in CALOR simulation code to model experimental configurations

CALOR89 code system is being used to simulate test beam results and the design parameters of several calorimeter configurations. It has been bench-marked against the ZEUS, D{theta} and HELIOS data. This study identifies the systematic effects in CALOR simulation to model the experimental configurations. Five major systematic effects are identified. These are the choice of high energy nuclear collision model, material composition, scintillator saturation, shower integration time, and the shower containment. Quantitative estimates of these systematic effects are presented. 23 refs., 6 figs., 7 tabs

Estimates of the neutron fluence for the SDC detector

The high energy and high luminosity of SSC cause radiation problems to detectors. Almost all the radiation in the SDC detector comes from the 20 TeV on 20 Tev pp collisions. The design luminosity corresponds to 10[sup 8] collisions per second. This luminosity is maintained for 10[sup 7] seconds (one SSC year). It is important to know the radiation fields experienced by the tracking volume, calorimeter, electronics and the phototubes. The loss of light due to the radiation damage to the scintillators can adversely affect the physics performance of the calorimeter. Studies have been carried out earlier to estimate the radiation dose in the SDC detector. In this note we use ISAJET in combination with CALOR89 to make an accurate prediction of neutron fluence at the various locations of the SDC detector. The low energy neutron fluence is important because of their large activation cross sections. In CALOR89 the low energy neutron fluence is accurately estimated by MORSE code

Design considerations for a scintillating plate calorimeter for SDC

As scintillating plate calorimetry is a viable option for the SDC detector, it is imperative that the phase space of passive and active materials be explored in a systematic fashion. To this end, we have examined several different configurations of passive and active materials as a function of incident energy, to see what the resolution and e/h characteristics are of each of these configurations. These studies have been carried out using the CALOR89 Monte Carlo simulation package. 3 figs., 5 tabs

Simulation of a presampler response with CALOR - a comparison with experimental data

SIGLEAvailable from TIB Hannover: RA 2999(92-045) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Simulation of hanging file experiments with CALOR89

This note presents the comparison of CALOR89 simulation with the hanging file'' test measurements conducted at Fermilab during the period of Sep 91--Jan 92. The purpose of this study is to benchmark CALOR89 code against the experimental data to enhance its reliability and predictive power. Seven hanging file configurations were simulated. The measured values of e/{pi} ratio (the ratio of electron to pion signal at the same energy), hadronic and electromagnetic resolutions were compared with the simulations. The depth profiles of the hadronic and electromagnetic showers are also compared

Unix version of CALOR89 for calorimeter applications

CALOR89 is a system of coupled Monte Carlo particle transport computer codes which has been successfully employed for the estimation of calorimeter parameters in High Energy Physics. In the past CALOR89 has been running on various IBM machines and on CRAY X-MP at Lawrence Livermore Lab. These machines had non-unix operating systems. In this report we present a UNIX version of CALOR89, which is especially suited for the UNIX work stations. Moreover CALOR89 is also been supplemented with two new program packages which makes it more user friendly. CALPREP is a program for the preparation of the input files for CALOR89 in general geometry and ANALYZ is an analysis package to extract the final results from CALOR89 relevant to calorimeters. This report also provides two script files LCALOR and PCALOR. LCALOR runs CALOR89 sequences of programs and EGS4 for a given configuration sequentially on a single processor and PCALOR concurrently on a multiprocessor unix workstation

Incident energy dependence of hadronic activity

Two features of high-energy hadronic cascades have been long known to shielding specialists: (a) in a high-energy hadronic cascade in a given material (incident E [approx equal] 10 GeV), the relative abundance and spectrum of each hadronic species responsible for most of the energy deposition is independent of the energy or species of the incident hadron, and (b) because [pi][sup 0] production bleeds off more and more energy into the electromagnetic sector as the energy of the incident hadron increases, the level of this low-energy activity rises less rapidly than the incident energy, and in fact rises very nearly as a power of the incident energy. Both features are of great importance in hadron calorimetry, where it is the universal spectrum'' which makes possible the definition of an intrinsic e/h, and the increasing fraction of the energy going into [pi][sup 0]'s which leads to the energy dependence of e/[pi]. We present evidence for the universal spectrum,'' and use an induction argument and simulation results to demonstrate that the low-energy activity scales as E[sup m], with 0.80 [le] m [le] 0.85

Measurement of the CP violating asymmetry amplitude sin 2beta

We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.034 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.030 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes.Comment: 7 pages, 2 postscript figures, submitted to PR