T. A. Gabriel

The GEANT - CALOR interface and benchmark calculations of ZEUS test calorimeters

Abstract The simulation of large scale high energy physics experiments is based mainly on the GEANT package. In the current version 3.15 the simulation of hadronic interacting particles is based on GHEISHA or FLUKA. Both programs miss an accurate simulation of the interaction of low energetic neutrons ( E kin

Energy dependence of hadronic activity

Two features of high-energy hadronic cascades have long been known to shielding specialists: a) in a high-energy hadronic cascade in a given material (incident E ≳ 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 π0 production bleeds off more and more energy into the electromagnetic sector as the energy of the incident hadron increases, the absolute level of this low-energy hadronic activity (E ≲ 1 GeV) 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 eh, and the increasing fraction of the energy going into π0s which leads to the energy dependence of eπ. We present evidence for the “universal spectrum,” and use an induction argument and simulation results to demonstrate that the low-energy activity ss Em, with 0.80 ≲ m ≲ 0.85. The hadronic activity produced by incident pions is 15–20% less than that initiated by protons.

R&D for the Spallation Neutron Source mercury target

An overview of the research and development program for the Spallation Neutron Source (SNS) is presented. The materials-related efforts in target development are emphasized in order to provide a perspective for a number of specialized papers that are included in these proceedings. We give a brief introduction and historical sketch of the SNS project. Part of the materials R&D consists of calculations of radiation damage and of transmutation rates. He and H are considered to be the most important transmutation products. Radiation effects and Hg compatibility investigations make up the major part of the experimental effort. In the former, spallation irradiations are carried out in the LANSCE at Los Alamos National Laboratory and in the SINQ at the Paul Scherrer Institute. Irradiations that simulate aspects of a spallation environment are included to extend the parameter space of the spallation irradiations. The simulations are carried out at the low energy (MeV) accelerators of the TIF facility and at the HFIR reactor, both located at Oak Ridge National Laboratory. Irradiated specimens are tested for changes in mechanical properties and are characterized with respect to microstructural changes by transmission electron microscopy. The compatibility experiments cover both the effects of Hg on behavior in mechanical properties tests, and the effects of flowing Hg on mass transfer in target structural materials. The results of this extensive program of materials work indicate that the target design and materials performance will meet their intended service.

Monte Carlo studies of uranium calorimetry

Abstract Detailed Monte Carlo calculations of uranium calorimetry are presented which reveal a significant difference in the responses of liquid argon and plastic scintillator in uranium calorimeters. Due to saturation effects, neutrons from the uranium are found to contribute only weakly to the liquid argon signal. Electromagnetic sampling inefficiencies are significant and contribute substantially to compensation in both systems.

Cross-sections for nuclide production in 1-GeV proton-irradiated Pb-208

114 cross sections for nuclide production in a 1.0 GeV proton-irradiated thin 208Pb target have been measured by the direct gamma spectrometry method using a high-resolution Ge detector. The gamma spectra were processed by the GENIE-2000 code. The ITEP-developed SIGMA code was used together with the PCNUDAT nuclear decay database to identify the gamma lines and to determine the cross sections. The 27Al(p,x)22Na reaction was used to monitor the proton flux. Results of a feasibility study of the auxiliary 27Al(p,x)24Na and 27Al(p,x)7Be monitor reactions in the 0.07-2.6 GeV proton-energy range are presented as well. Most of the experimental data have been analyzed by the LAHET (with ISABEL and Bertini options), CEM95, CEM2k, INUCL, CASCADE, CASCADE/INPE, and YIELDX codes that simulate hadron-nucleus interactions.

The mid-rapidity calorimeter for the relativistic heavy-ion experiment WA80 at CERN

Abstract A sampling calorimeter designed for use at mid-rapidity in the relativistic heavy-ion experiment WA80 at CERN is described. Calibration and performance results are presented. Over the energy range of 2 to 50 GeV, the response of the mid-rapidity calorimeter was linear, and its energy resolution σ E was found to be given by 0.014 + 0.11 √E and 0.034+0.34 √E for electromagnetic and hadronic showers, respectively. Signal ratios of 1.2 and 1.4 were obtained for the e h ratio of the lead-scintillator electromagnetic section and the iron-scintillator hadronic section, respectively. The calorimeter provided an accurate transverse energy trigger. The response and resolution for high-energy heavy ions were slightly better than anticipated on the basis of the low-energy calibrations.

Cascade-exciton model analysis of proton induced reactions from 10 MeV to 5 GeV

We have used an extended version of the Cascade-Exciton Model (CEM) to analyze more than 600 excitation functions for proton induced reactions on 19 targets ranging from C-12 to Au-197, for incident energies ranging from 10 MeV to 5 GeV. We have compared the calculations to available data, to calculations using approximately two dozen other models, and to predictions of several phenomenological systematics. We present here our conclusions concerning the relative roles of different reaction mechanisms in the production of specific final nuclides. We comment on the strengths and weaknesses of the CEM and suggest possible further improvements to the CEM and to other models.

The zero-degree calorimeter for the relativistic heavy-ion experiment WA80 at CERN

Calibration and performance results are presented for a sampling calorimeter designed for use as a beam calorimeter at zero degrees in the relativistic heavy-ion experiment WA80 at CERN. This uranium-scintillator zero-degree calorimeter (ZDC) was found to have a linear response to heavy ions over the range 60–6400 GeV and an in-beam hadronic resolution ranging from σE = 0.013 + 0.33√E at low intensities to σE = 0.02 + 0.67√E at higher intensities. The eh ratio of the electromagnetic section was measured to be 1.12 at 135 GeV. The ZDC operated reliably with incident beams of 3.2 TeV oxygen and 6.4 TeV sulfur at intensities of over 106 nuclei per spill. It provided a trigger both for minimum bias events and for violent central collisions.

A modular straw drift tube tracking system for the Solenoidal Detector Collaboration experiment Part I. Design

Abstract We have developed the baseline design for a straw drift tube tracking system for the Solenoidal Detector Collaboration (SDC) detector. The system was designed to operate in the high-rate environment of a high luminosity hadron collider. We present an overview of the tracking system and the requirements it was expected to fulfill. We describe the construction and properties of the straw drift tubes. We discuss the design of the carbon-fiber foam-laminate shell, which supported the wire tension and held the straws in alignment. We also present descriptions of the designs of the front-end and digitization electronics as well as the electronics associated with the level 1 track trigger.

A High-Power Target Experiment

We describe an experiment designed as a proof-of-principle test for a target system capable of converting a 4-MW proton beam into a high-intensity muon beam suitable for incorporation into either a neutrino factory complex or a muon collider. The target system is based on exposing a free mercury jet to an intense proton beam in the presence of a high-strength solenoidal magnetic field.