135998449
Dense, fast, radiation-tolerant Fluoro-Hafnate glass scintillators for electromagnetic calorimeters in high energy physics
14766409
The front-end driver card for the CMS silicon strip tracker readout
The first prototypes of the production version of the Front-End Driver (FED) card for the CMS silicon strip tracker are about to be manufactured. The FEDs provide the off-detector processing of the tracker readout system. They digitise and zero-suppress the multiplexed analogue optical data sent on each Level-1 trigger from the ondetector APV25 pipeline chips. This paper outlines the design and describes in detail the implementation of the 96 ADC channel, 9U VME64x form factor card. In total, 440 FEDs will be required to readout the silicon strip tracker.
123620409
Photon radiation from quarks at OPAL
Abstract Two recent results from OPAL on photon radiation in hadronic Z 0 decays are presented. The first is the first measurement at LEP of the quark to photon fragmentation function via the inclusive production of prompt photons. The second is an attempted test of QCD shower models via the production of isolated prompt photons.
122418971
The Reaction $\pi^- p \to K^0 \Lambda^0$ Up to 2375-{MeV}/$c$: New Results and Analysis
Abstract New data are presented on the reaction π − p→K 0 Λ 0 at 13 incident momenta between 1395 and 2375 MeV/ c . A partial-wave analysis has been performed using these data and previous data at lower momenta. The resulting resonance parameters are in broad agreement with recent πN analyses and with the predictions of SU(6) W × O(3) for the couplings.
121364230
The development of vacuum phototriodes for the CMS electromagnetic calorimeter
Abstract A new generation of vacuum phototriodes (VPTs) has been developed for application in the end-cap sub-system of the crystal electromagnetic calorimeter (ECAL) for the CMS experiment at the CERN Large Hadron Collider (LHC). These VPTs must operate with high reliability for at least 10 years in an extremely hostile environment. Results are presented from an extensive programme of tests, demonstrating that the required properties of significant gain in a 4 T magnetic field, resistance to ionising radiation, and stable operation with large photocurrents can all be satisfied in a robust, compact, inexpensive device.
15192778
Design of the front-end driver card for CMS silicon microstrip tracker readout
The CMS silicon microstrip tracker has approximately 10 million readout channels. The tracking readout system employs several hundred off-detector Front-End Driver (FED) cards to digitise, sparsify and buffer analogue data arriving via optical links from on-detector pipeline chips (APVs). This paper describes the baseline design of the FrontEnd Driver card which is implemented with a 96 ADC channel (10 bits) 9U VME board. Under typical LHC operating conditions the total input data rate per FED after digitisation is 3 GBytes/s and must be substantially reduced. The required digital data processing is highly parallel and heavily pipelined and is carried out in several large FPGAs. The employment of modern FPGA simulation tools in the design of a VHDL model of the FED is discussed.
118898339
Using FU Orionis Outbursts to Constrain Self-Regulated Protostellar Disk Models
One dimensional, convective, vertical structure models and one dimensional, time dependent, radial diffusion models are combined to create a self-consistent picture in which FU~Orionis outbursts occur in young stellar objects (YSOs) as the result of a large scale, self-regulated, thermal ionization instability in the surrounding protostellar accretion disk. By fitting the results of time dependent disk models to observed time scales of FU~Orionis events, we estimate the magnitude of the effeciency of the effective viscous stress in the inner disk (r < 1 AU) to be, in accordance with the ad hoc ``alpha'' prescription, 10^{-4} where hydrogen is neutral and 10^{-3} where hydrogen is ionized. We hypothesize that all YSOs receive infall onto their outer disks which is steady (or slowly declining with time) and that FU~Orionis outbursts are self-regulated, disk outbursts which occur only in systems which transport matter inward at a rate sufficiently high to cause hydrogen to be ionized in the inner disk. We estimate a critical mass flux of 5x10^{-7} solar masses / year {\it independent of the magnitude of alpha} for systems with one solar mass, three solar radius central objects. Infall accretion rates in the range of (1-10)x10^{-6} solar masses per year produce observed FU~Orionis time scales consistent with estimates of spherical molecular cloud core collapse rates.