[en] This paper presents first results on mechanical and cooling studies for a 3D silicon vertex detector designed for B physics at a hadron collider. Prototype modules were built from raw silicon wafers. One module was instrumented with resistors to simulate readout electronics. Both module movement and temperature variations were recorded. A cooling method utilizing simple air/helium flow was investigated, but proved inadequate because of too large temperature anisotropies. (orig.)

[en] A circuit has been designed for digitizing PMT signals over a wide dynamic range (17-18 bits) with 8 bits of resolution at rates up to 53 MHz. Output from the circuit is in a floating point format with a 4 bit exponent and an 8 bit mantissa. The heart of the circuit is a full custom integrated circuit called the QIE (Charge Integrator and Encoder). The design of the QIE and associated circuitry reported here permits operation over a 17 bit dynamic range. Test results of a multirange device are presented for the first time. (orig.)

[en] A series of commercially available coumarins was tested as wavelength shifters in polystyrene for a tile/fiber calorimeter application. The objective was to find a compound that when incorporated in a polystyrene matrix absorbed in the 400-450 nm wavelength range, fluoresced in the green region of the visible spectrum (λ_em=450-550 nm), and exhibited both short decay time and high quantum yield. Transmittance, fluorescence, and decay time determinations were performed in order to characterize each coumarin in polystyrene. Two coumarins (C510 and C515) were found to have faster decay times ( similar 8 ns vs. 12 ns) and superior light output (100-120%) compared to the commonly-used green wavelength shifter, K-27. (orig.)

[en] We report our experimental demonstration of longitudinal phase space modulation using a transverse-to-longitudinal emittance exchange technique. The experiment is carried out at the A0 photoinjector at Fermi National Accelerator Lab. A vertical multi-slit plate is inserted into the beamline prior to the emittance exchange, thus introducing beam horizontal profile modulation. After the emittance exchange, the longitudinal phase space coordinates (energy and time structures) of the beam are modulated accordingly. This is a clear demonstration of the transverse-to-longitudinal phase space exchange. In this paper, we present our experimental results on the measurement of energy profile as well as numerical simulations of the experiment.

[en] Using the E791 spectrometer we have tested a multiplicity jump trigger that makes use of thin quartz plates to count the number of particles before and after a decay region just downstream of a thin tungsten target struck by a 500 GeV pion beam. The detector is sensitive to about 2.7 tracks being created between the plates at the 1 sigma level. This performance level may enhance charm events by a small amount, and should lead to an enrichment of well over 100 for B anti B events. (orig.)

[en] This proceeding contains papers on proton-antiproton collider physics. Included are the following topics: W, Z, physics, minimum bias physics, QCD jets, new detector technology, accelerator upgrades, heavy flavor production and physics beyond the standard model

[en] A model for the onset of the reduction in SRF cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration H_pen. Such defects were argued to be the worst case by Buzdin and Daumens, (1998 Physica C 294 257), whose approach, moreover, incorporates both the geometry of the groove and local contamination via the Ginzburg-Landau parameter κ. Since previous Q-drop models focused on either topography or contamination alone, the proposed model allows new comparisons of one effect in relation to the other. The model predicts equivalent reduction of H_pen when either roughness or contamination were varied alone, so smooth but dirty surfaces limit cavity performance about as much as rough but clean surfaces do. Still lower H_pen was predicted when both effects were combined, i.e. contamination should exacerbate the negative effects of roughness and vice-versa. To test the model with actual data, coupons were prepared by buffered chemical polishing and electropolishing, and stylus profilometry was used to obtain distributions of angles. From these data, curves for surface resistance generated by simple flux flow as a function of magnetic field were generated by integrating over the distribution of angles for reasonable values of κ. This showed that combined effects of roughness and contamination indeed reduce the Q-drop onset field by ∼20%, and that that contamination contributes to Q-drop as much as roughness. The latter point may be overlooked by SRF cavity research, since access to the cavity interior by spectroscopy tools is very difficult, whereas optical images have become commonplace. The model was extended to fit cavity test data, which indicated that reduction of the superconducting gap by contaminants may also play a role in Q-drop.

[en] The p yield at 8.89±0.18 GeV has been measured for different lithium collection lens gradients and lens to target distances. Using an empirical p production and collection model, the yield as a function of production angle and vertex position in the target has been extracted. Data taken for different targets indicates that the p yield varies little as a function of atomic weight. A reduction in the Re target yield due to target melting was measured for the nominal proton intensity on target. An enhancement in Cu p production was observed for proton beam targeted very near the interface with a lighter material (Al) disk. (orig.)

[en] The addition of photosensitive dopants to liquid argon greatly enhances the signal from heavily ionizing particles. Since binding energy losses are correlated with the heavily ionizing component in hadronic showers, the addition of photosensitive dopants has been suggested as a mechanism to tune the e/π ratio in liquid argon calorimeters. A measurement was performed at the FNAL test beam, adding 4 ppm tetramethylgermanium to the D0 uranium-liquid argon calorimeter. An increase in response for electromagnetic and hadronic showers was observed, with no net change in the e/π ratio. (orig.)

[en] Over the recent years, the emergence of accelerator beamlines capable of exchanging the phase space coordinates between two degrees of freedom have opened the path toward the precise control of phase space distribution and in particular to the production of relativistic electron beams with shaped current profiles. After briefly reviewing the technique, we present its application to produce a train of sub-picosecond microbunches and report on its experimental implementation at the Fermilab's A0 photoinjector facility.