Intermittency at Intermediate Energies*
Apart from some misunderstandings of this summer, recent developments have led to considerable progress in this controversial but challenging eld. Intermittency is now established as an eeect in at least two dimensions, where it has turned out to be stronger and cleaner than in one. The eeect is strongest in lh and e + e ? collisions. In hh colisions, where the energy range covered is the largest, the eeect is stronger at intermediate then at high p s. Next to parton showering, intermittency is very sensitive to the soft phase, which will have to be studied with large statistics at intermediate energies, where it is not overshadowed by hard eeects. In terms of the space-time development of a scattering process, the intermittency phenomenon and the determination of its parameters are shown to give a genuine information on the nature of hadronization at large distances compared to the hard interaction region. As such, it is expected to be sentitive to the nuclear environment of a deep-inelastic electron collision. In recent years events have been observed containing high particle density \spikes" in rapidity space. Fig.1a shows the JACEE event 1] at a pseudo-rapidity resolution of =0.1 unit, with local uctuations up to dn== 300 and with a signal to background ratio of about 1:1. The NA22 event 2] of Fig.1b contains a rapidity \spike" of dn=dy=100 at a rapidity resolution y=0.1. This corresponds to 60 times the average density in this experiment. Also UA5 3] has reported \spikes" of dn=dd up to 30 (10 times average) as early as JACEE, but found these to be in agreement with a short range cluster Monte Carlo. No doubt, local density uctuations exist. The question is whether they are of statistical or dynamical origin, whether the underlying probability density is continuous or intermittent. To study these, Biaa las and Peschanski 4] have suggested to study the dependence of scaled factorial multiplicity moments
Fractal structures and intermittency in perturbative QCD cascades
New results are presented for fractal structures and intermittency in QCD parton showers. The particle momenta define a fractal curve in energy-momentum space with a dimension which is asymptotically equal to 1 + √3αs/2π. This gives a geometrical interpretation of the anomalous dimension in QCD. For the distribution in small angular regions we see that the corresponding multifractal dimension are the same if we bin in y or Ψ or do a two-dimensional analysis in y and Ψ.
Long Ceramic Beam Tubes for Accelerator Magnets
The ceramic beam tubes for the fast and abort kickers and the bucker and pinger magnets used at Fermilab must meet a number of exacting requirements. The tubes must be long and sufficiently straight so as not to limit magnet design. They must have wall strength capable of withstanding the atmospheric and mechanical forces encountered during construction and operation. Vacuum tight ceramic to stainless steel transitions must be of reasonable cost; they must also withstand high temperature processing and remain vacuum tight to the 10/sup -9/ Torr range. To remove the possibility of static charge buildup each tube must have a surface coating of indium oxide applied to the inner wall. This thin coating is difficult to achieve and requires the most careful attention to detail. The methods used at Fermilab to achieve these goals are presented in this paper.