Level 3 system at CDF

Level 3 uses 32-bit microprocessors installed in VME crates to execute FORTRAN filter algorithms. The system is integrated into the CDF FASTBUS data acquisition network which is designed to support event rates of 100 Hz into level 3. Filter algorithms access event data in the same detector bank format as used for off-line analysis.     

CDF central muon level-1 trigger electronics

We present the level-1 trigger module used for the CDF central muon drift chambers. Addressable registers select trigger mode for calibration, debugging, or data acquisition. A transverse momentum cut on muons exiting the solenoidal magnetic field region is made by using drift time differences between aligned pairs of anode sense wires. Cosmic ray results are presented and track angle selection is shown to be better than 5 mrad.     

The CDF forward muon system

The general properties of the toroids, drift chambers and trigger counters in the CDF forward muon (FMU) system are discussed. The operation of the PSL time-to-digital converter and the UW HOPU (Half Octant Pattern Unit) module is also described. The forward muon level 1 trigger is presented.     

CDF front end electronics: The rabbit system

A new crate-based front end system has been built featuring low cost, compact packaging, fast readout, command capability, 16 bit digitization, and a high degree of redundancy. The crate can contain a variety of instrumentation modules and is designed to be placed near the detector. Remote, special purpose processors direct the data readout. Channel-by-channel pedestal subtraction and threshold comparison in the crate allow the skipping of empty channels. The system is suitable for the readout of a very large number of channels.     

Phototube testing for CDF

Photomultiplier tubes for the Collider Detector at Fermilab were subjected to preinstallation testing for stability, linearity and other properties. An apparatus is described which provided computer control of light sources, monitoring of environmental conditions and data logging of responses from up to 48 photomultipliers simultaneously. Statistical summaries of the test results are included for 1041 tubes for the central electromagnetic calorimeter and 687 tubes for the endwall hadron calorimeter.     

CDF central muon detector

Design, construction and performance characteristics of the streamer chambers for the central muon detector at CDF are described. A single hit TDC is used for measurements in the drift (azimuth) direction while charge division is used for measurements along the sense wire (pseudorapidity). The chambers operate in the limited streamer mode with a 50%/50% ratio of argon/ethane bubbled through ethanol. Measurements in a cosmic ray test stand, pion test beam and as part of the CDF detector indicate that an rms resolution of 250 μm in the drift direction and an rms resolution of 1.2 mm along the sense wire are attainable.     

Fastbus data acquisition for CDF

All CDF event data are collected in a multilevel FASTBUS network. At the lowest level of this network, MEP/MX and SSP scanners read and buffer data from RABBIT and FASTBUS front end systems. Operation of these front end scanners is coordinated by the Trigger Supervisor module which initiates parallel readout after receiving Level 1 and Level 2 triggers. Dataflow from scanners to consumer processes on host VAX computers is supervised by the Buffer Manager which directs an Event Builder to collect and format data from a set of scanner modules. This system is designed to allow partitioning into semi-independent sections for parallel development and calibration studies.     

The CDF plug upgrade electromagnetic calorimeter: test beam results

The CDF Plug Upgrade calorimeter, which fully exploits the tile–fiber technique, was tested at the Fermilab meson beamline. The calorimeter was exposed to positron, positively charged pion and positive muon beams with energies in the range of 5–230 GeV. The energy resolution of the electromagnetic calorimeter to the positron beam is consistent with the design value of , where E is the energy in units of GeV and represents sum in quadrature. The non-linearity for positrons is studied in an energy range of 11–181 GeV. It is important to incorporate the response of the preshower detector, the first layer of the electromagnetic calorimeter which is readout separately, into that of the calorimeter to reduce the non-linearity to 1% or less. The energy scale is about 1.46 pC/GeV with HAMAMATSU R4125 operated typically at a gain of 2.5×10⁴. The response non-uniformity over the surface of a tower of the electromagnetic calorimeter is found to be about 2% with 57 GeV positrons. Studies of several detailed detector characteristics are also presented.     

CDF计算程序的可靠性分析

就自编圆柱分布函数ＣＤＦ９２型计算程序的可靠性进行了分析，并以聚酯ＰＥＴ取向非晶薄膜的二维相干散射强度为例进行具体计算，指出了获得可靠的ＣＤＦ应具备的判断依据。     

Freeze-thaw and deicing salt resistance of concrete testing by the CDF method CDF resistance limit and evaluation of precision

RILEM TC 117-FDC decided unanimously that the precision of any freeze-thaw and deicing test procedure must be assessed in accordance with ISO 5725. In addition, a resistance limit for concrete should be approved with respect to practical performance. In this article it is shown that these requirements are fulfilled by the CDF test (capillary suction of deicing chemicals and freeze-thaw test). To verify this, different compositions covering the design rules as defined by standards and given by long-term experience have been measured. The repeatability covering the scatter of the materials and the test procedures was calculated using a large data base of 400 tests. To determine the reproducibility, which includes repeatability and between laboratory scatter, 26 comparison tests between two universities, one internal and two European round robin tests were evaluated additionally. The mean scaling after 28 cycles (14 days) at 1500 g m^?2 proved to be a reliable CDF resistance limit. At this level a coefficient of variation for repeatability has been established at 11% and for reproducibility at 18%. An acceptance criterion may be proposed for further discussion at 1800 g m^?2 as the upper 5% fractile. This minimizes the risk for both customer and supplier.     

Radial wire drift chambers for CDF forward tracking

We describe the design, construction, and operating experience of unique drift chambers with radially strung wires for the Collider Detector of Fermilab (CDF) [1] which cover forward and backward cone angles between 2° and 10°, and 170° and 178°. The chambers are capable of operating in our high rate and high track multiplicity environment with excellent multitrack resolution of 2–3 mm and high tracking accuracy of 140 μm per wire. Results from the recent running experience will be presented.     

CDF分析方法及其计算程序研究

本文讨论了圆柱分布函数ＣＤＦ分析法的基本原理，在此基础上用Ｆｏｒｔｒａｎ语言编写了通用性较强的ＣＤＦ９２型程序，并已用于ＰＥＴ取向非晶态结构分析。     

CDF型双正交小波之间构造关系的研究

以提升的方法,对CDF型双正交小波之间的构造关系进行了讨论。应用文中提到的算法一,给出了Cohen文中原来三组CDF型小波中,每组内的小波顺次逐一提升的关系;再用算法一结合平面束理论得到与Cohen文中12个CDF型小波不同的8个小波;还给出了算法二,并讨论了寻求两个已知CDF型小波之间提升算子S(ω)的问题。