Fast shower simulation based on Gau. Beta. 's law

I have developed a procedure for fast shower simulation on the basis of Gau{beta}'s law, applied in analogy to charge distributions and related vector fields of electromagnetic interactions. The nature of a shower (i.e. electromagnetic or hadronic), a homogeneous medium for its development, its starting point, direction and energy content are needed to be specified. Then the contribution from the shower to the total signal in any given volume made up of the given medium can be calculated as an integral over the surface of that volume using a precalculated vector field corresponding to the shower distribution. Thus the integration problem is reduced from three to two dimensions. The quality of the shower simulation is determined by the accuracies of the vector fields and of the surface integration. This technique is shown to yield acceptable results for typical sized of calorimeter cell structures. 19 refs., 4 figs

On the scattering of atmospheric muons in the rock above Soudan 2

I have investigated the effect of scattering in the rock overburden on the position and direction of atmospheric muons as observed at the Soudan 2 detector relative to the surface. The dominant contributions to the fluctuations in those observables arise from multiple Coulomb scattering and delta ray production. The contribution of the other energy loss mechanisms, bremsstrahlung, pair production and nuclear interactions, is small, with slowly increasing importance at very large deviations from the means of the distributions

On the massless gap'' adjustment of detected energy for passive material in front of a calorimeter

I have designed a correction scheme for energy losses in passive material in front of a calorimeter based on the massless gap'' idea. I use a flexible geometry model of a calorimeter design for SDC outside of a solenoidal coil made of aluminium cylinders of adjustable thickness. The signal from the first radiation length of active calorimetry is scaled dependent on the incoming and observed energies of the shower. A reasonable recovery of the resolution of an unobstructed calorimeter is achieved using correction factors that depend only upon the total thickness of passive material. Thus a useful correction may be built into the hardware by increasing the amount of scintillator in the first radiation length of the active calorimeter. The distribution of correction factors determined event-by-event indicate that an additional dependence on the observed signal in the massless gap and total incident energy is clearly present

Eine globale Analyse der elastischen He-Streuung im Rahmen des optischen Modells

SIGLEDEGerman

Some physics requirements for triggering in the intermediate tracking system of SDC

I have investigated trigger requirements for the intermediate tracking system of the SDC detector, using muons in the final states of some physics processes of interest and relevance to the program envisaged to be pursued at the SSC. The study is done at the physics event generator level with the PYTHIA package, augmented by a very simplistic simulation of the momentum measurement expected from the intermediate tracking system. For the range in pseudorapidity of {vert bar}{eta}{vert bar} = 1.7--2.5, I find a subdivision into four basic bins sufficient to ensure that the width of the transverse momentum trigger threshold will not be dominated by the lack of knowledge of the polar angle. In addition, the azimuthal resolution has be better than 1 mrad to allow transverse momentum thresholds from p{sub t}{approx}10 GeV/c up to and beyond p{sub t}=20 GeV/c to be implemented which are needed to accomplish the physics goals. 10 figs., 1 tab

The effect of passive material on the detection of hadrons in calorimeter configurations for the SDC detector

We have used a flexible geometry model of a calorimeter design for SDC to study the effect of passive material in front of the calorimeter and between the barrel and endcap modules on the apparent response to hadrons. The thicknesses of the passive materials have been chosen to closely resemble the currently projected wall thicknesses of the scintillating tile-fiber and liquid-argon calorimeter designs. The liquid-argon model contains about three times the amount of material in its shells compared to the tile-fiber model. The solenoid coil reduces the relative difference somewhat in the barrel region but constitutes only a minor correction in the transition region from barrel to endcap. Correspondingly, we find a significantly worse response for the liquid-argon case which we demonstrate using beams of single {pi}{sup minus} particles of 10 GeV/c momentum. 13 refs., 6 figs

A first simulation study of the barrel-endcap transition region in a calorimeter of the scintillator tile design

We have made a first study of the calorimetric response to 10 GeV/c charged pions in the transition region between barrel and endcap for the scintillator-tile design pursued at Argonne National Laboratory using the simulation program ANLSIM. For (very nearly) projective tower orientations in the barrel, the crack appears deep within a narrow angular range, causing a loss of the response in that region up to 40%. Pointing the towers onto the beam axis 35 cm or more away from the nominal-interaction point leads to a shortened depth of the barrel-endcap crack as seen by particles incident from the interaction region, cutting the maximum loss down by almost one half. The worsening of the resolution follows the same trend. Introduction of a solenoidal coil in front of the calorimeter causes an overall degradation of the response by an amount nearly comparable to the effect of the crack. Electrons of the same incident momentum are more strongly affected by the coil than pions but see only a much narrower region of degradation by the crack. 15 refs., 6 figs., 2 tabs