A PMT-Block test bench

The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called {\it PMT-Block}. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its divider and a {\it 3-in-1} card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterisation are described in detail in this report. The results obtained in the test of about 10000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.Comment: 23 pages, 10 figure

The electrophysical and optical properties of gadolinium monoantimonide thin films

Within a wide temperature interval 90 – 700 K the main the dependence of electro-physical parameters of GdSb films (specific resistance, Hall constant and thermo-electromotive force) on temperature have been measured. It has been shown that the films are semimetals. The reflection and adsorption spectra of prepared films have been studied for the first time within the intervals of 0.05 – 5.5 eV. On the basis of received data the diagram of the dependence of penetration real part and loss functions on the photon energy have been plotted. It has been shown that the spectra of optical parameters have quite a complex nature.Разработана технология приготовления тонких кристаллических плёнок GdSb методом вакуумно-термического испарения из двух независимых источников Gd и Sb, в широком интервале температур 90 – 700 K. Исследованы температурные зависимости удельного электросопротивления, постоянной Холла и термо-ЭДС. Показано, что пленки являются полуметаллами. В области энергии фотонов 0.05 – 5.5 эВ измерены спектры отражения и поглощения. В результате полученных данных вычислены энергетические зависимости деиствительной и мнимой части диэлектрической проницаемости, а также функции потерь. Исследования выявили сложный характер оптических параметров изготовленных плёнок.Розроблена технологія приготування тонких кристалічних плівок GdSb методом вакуумнотермічного випаровування із двох незалежних джерел Gd і Sb, у широкому інтервалі температур 90 – 700 K. Досліджені температурні залежності питомого електроопору, постійної Хола і термо-ЕРС. Показано, що плівки є напівметалами. В області енергії фотонів 0.05 – 5.5 еВ виміряні спектри відбиття і поглинання. У результаті отриманих даних обчислені енергетичнізалежності дійсної та уявної частини діелектричної проникності, а такожфункції втрат. Дослідження виявили складний характер оптичних параметрів виготовлених плівок

A study of the etapipi channel produced in central pp interactions at 450 GeV/c

The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870). In addition, there is evidence for an a0(980)pi$ decay mode of both resonances and an f2(1270)eta decay mode of the eta2(1870). No evidence is found for a JPC = 2++ a2(1320)pi wave.Comment: 15 pages, Latex, 4 Figures Branching ratio a2pi /f2 eta correcte

A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4pi final states

The production and decay properties of the f0(1370), f0(1500), f0(2000) and f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT, phi and |t| distributions of these resonances are presented. For the J = 0 states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These are different to the dPT and phi dependences of the f0(980), f0(1500) and f0(1710). For the J = 2 states the f2(1950) has different dependences to the f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not just J phenomena.Comment: 14 pages, Latex, 4 Figure

A search for charmonium states produced in central pp interactions at 450 GeV/c

A search for centrally produced charmonium states has been presented. There is no significant evidence for any charmonium production. An upper limit of 2 nb is found for the cross section of chic production using the decay chic(1P)-> J/psi gamma.Comment: 10 pages, Latex, 4 Figure

A study of the centrally produced pi0pi0pi0 channel in pp interactions at 450 GeV/c

The reaction pp -> pf (pi0pi0pi0) ps has been studied at 450 GeV/c. The pi0pi0pi0 effective mass spectrum shows clear eta(547) and pi2(1670) signals. Branching ratios for the eta(547) and pi_2(1670) are given as well as upper limits for the decays of the omega(782), a1(1260) and a2(1320) into 3pi0.Comment: 10 pages, Latex, 4 Figure

A coupled channel analysis of the centrally produced K+K- and pi+pi- final states in pp interactions at 450 GeV/c

A coupled channel analysis of the centrally produced K+K- and pi+pi- final states has been performed in pp collisions at an incident beam momentum of 450 GeV/c. The pole positions and branching ratios to pipi and KK of the f0(980), f0(1370), f0(1500) and f0(1710) have been determined. A systematic study of the production properties of all the resonances observed in the pi+pi- and K+K- channels has been performed.Comment: 16 pages, Latex, 5 Figure

Experimental evidence for a vector-like behaviour of Pomeron exchange

Evidence is presented that the Pomeron act as a non-conserved vector current. A study has been made of the azimuthal angle phi, which is defined as the angle between the pT vectors of the two outgoing protons, in the reaction pp -> pp(X0) for those resonances (X0) which are compatible with being produced by double Pomeron exchange. These distributions have been compared with a model which describes the Pomeron as a non-conserved vector current and a qualitative agreement is found. In addition, when one of the particles exchanged is known to have spin 0, namely pi-Pomeron exchange, the phi distribution is flat.Comment: 13 pages, Latex, 4 Figure

A study of the centrally produced baryon-antibaryon systems in pp interactions at 450 GeV/c

A study of the centrally produced ppbar, ppbarpi, ppbarpipi and lambda lambda channels has been performed in pp collisions using an incident beam momentum of 450 GeV/c. No significant new structures are observed in the mass spectra, however, important new information on the production dynamics is obtained. A systematic study of the production properties of these systems has been performed and it is found that these systems are not produced dominantly by double Pomeron exchange.Comment: 13 pages, Latex, 4 Figure