L. Fiore

Complex fragments of 3<Z⪅35 have been detected in the reverse-kinematics reactions of 93Nb plus 9Be, 12C and 27Al at bombarding energies of E/A=11.4, 14.7 and 18.0 MeV. Velocity spectra and angular distributions show the presence of projectile and target-like components along with a component isotropic (in the reaction plane). This latter component aappears as a Coulomb ring in the invariant cross section plots indicating the presence of a binary decay which is confirmed by the coincidence data. Statistical model calculations indicate that for the Nb+Be and C reactions, the isotropic component is associated with the binary decay of compound nuclei formed in complete fusion reactions. The charge distributions for these two systems are consistent with the conditional barriers predicted with the rotating finite-range model. For the Nb+Al reactions, there is an additional isotropic component besides compound nucleus decay, which may arise from fast fission.

Complex fragments with 4 ⩽ Z ≲ 50 have been detected in the reactions of 139La + 12C and 27Al at E/A = 14.7 and 18.0 MeV. From the measured angular distributions, the cross sections for the isotropic, target-like and projectile-like components were extracted. The roles of deep-inelastic, fast-fission, and incomplete fusion processes, and the statistical, compound nucleus emission of complex fragments are discussed.

Inflammatory bowel disease (IBD) is the results of a chronic inflammatory process deriving from disequilibrium between self-microbiota composition and immune response.New evidence, coming from Clostridium difficile infection, clearly showed that active and powerful modulation of microbiota composition by fecal microbiota composition (FMT) is safe, easy to perform, and efficacious, opening new frontiers in gastrointestinal and extra-intestinal diseases. FMT has been proposed also for IBD as well as other non-gastrointestinal conditions related to intestinal microbiota dysfunctions, with good preliminary data.In this setting, ulcerative colitis (UC) represents one of the most robust potential indications for FMT after C difficile colitis.In the present review, we focus on FMT and its application on ulcerative colitis, clarifying mechanisms of actions and efficacy data, trough completion of a meta-analysis on available randomized, controlled trial data in UC. Because microbiota is so crucially involved in this topic, a short review of microbial alterations in UC will also be performed.

Two-neutron relative-momentum correlation functions have been measured in the 130 MeV $^{18}\mathrm{O}$ + $^{26}\mathrm{Mg}$ reaction. Differences in the longitudinal and transverse correlation functions, observed for the first time for neutrons, allow an independent determination of the spatial extent and the time scale for decay of the $^{44}\mathrm{Ca}$ compound nucleus. A comparison with theoretical calculations indicates a radius of 4.4\ifmmode\pm\else\textpm\fi{}0.3 fm and an average neutron emission time scale of 1100 \ifmmode\pm\else\textpm\fi{} 100 fm/c for $^{44}\mathrm{Ca}$ at 100 MeV excitation energy. Correlation functions selected by cuts on the total momentum of the neutron pair give a quantitative characterization of the cooling of a compound nucleus.

A compact and portable beam telescope has been built using four 1.92 × 1.92 cm2 double sided silicon microstrip detectors with 50 μm read-out pitch. Tests using 50 GeV pions have shown that the beam position can be defined with a precision of 5 and 7 μm on the p-side and n-side respectively with an overall detection efficiency of 93.0%.

The \ensuremath{\alpha} decay of Ru compound nuclei populated in $^{32}\mathrm{S}$ on $^{58}$,60,62,64Ni reactions at ${E}_{\mathrm{beam}=135--}$185 MeV has been studied. Experimental data have been compared with statistical model calculations performed with two different computer codes. The quality of the agreement between calculations and experimental data was found, in one case, to depend on the compound nucleus populated. Comparing the results from the two computer codes, deviations in the predicted cross sections are evidenced which are due to the different parametrization of nuclear properties employed in the calculations. Statistical model calculations describe well the shape of experimental spectra if account is taken of changes in the phase space available to the decaying nucleus which are related to the onset of deformations at high spins. Fission competition strongly determines the alpha-particle cross sections at the higher bombarding energies which are systematically underestimated by the model calculations if transmission coefficients computed from optical model potentials are used.

Interstrip and backplane capacitances on silicon microstrip detectors with p+ strip on n substrate of 320μm thickness were measured for pitches between 60 and 240μm and width over pitch ratios between 0.13 and 0.5. Parametrisations of capacitance w.r.t. pitch and width were compared with data. The detectors were measured before and after being irradiated to a fluence of 4×1014protons/cm2 of 24GeV/c momentum. The effect of the crystal orientation of the silicon has been found to have a relevant influence on the surface radiation damage, favouring the choice of a 〈100〉 substrate. Working at high bias (up to 500 V in CMS) might be critical for the stability of detector, for a small width over pitch ratio. The influence of having a metal strip larger than the p+ implant has been studied and found to enhance the stability.

When observed in singles, complex fragments associated with the 18A-MeV $^{139}\mathrm{Ni}$ reaction present a complex invariant-cross-section pattern without an obvious source, while the center-of-mass velocities of the coincident binary events span the entire range from complete fusion to near projectile velocities. By gating on a given value of the source velocity, it is possible to characterize precisely the product formed in the corresponding incomplete-fusion process and its decay.

Charged particles and high energy \ensuremath{\gamma} rays from the decay of the $^{156}\mathrm{Er}$ compound nucleus populated at ${\mathit{E}}_{\mathit{x}}$=47 MeV excitation energy by the $^{12}\mathrm{C}$${+}^{144}$Sm and $^{64}\mathrm{Ni}$${+}^{92}$Zr reactions have been measured to study possible nonstatistical or entrance channel effects. The experimental spectra and published evaporation residue and neutron data are compared with statistical model calculations. The comparison shows that the statistical model with standard parametrization of level density and yrast lines describes reasonably well the bulk of experimental observables but not the shape of neutron spectra if account is taken of the enhancement factor for E2 transitions. The discrepancies between experimental data and model calculations are discussed.

Abstract The photofission cross-section of 238U has been measured at six energies between 5.43 and 7.72 MeV, using nuclear emulsions and monochromatic γ-rays. The existence of minima in this energy region, suggested by previous workers, has been confirmed.

Thorium-loaded nuclear emulsions have been exposed to mono-energetic γ-rays obtained from (n, γ) reactions on the following elements: S, Dy, Y, Ca, Ti, Be, Mn, Pb, Fe, Al, Cu and Ni. The photo-fission cross section of 232Th has been measured at 12 energies in the range 5.4–9 MeV. For the same energies, the ratios of the 232Th cross section with respect to 238U are also given.

An array for neutron spectroscopy in low and intermediate-energy heavy-ion reactions is here described. The array is made of cylindrical liquid scintillator cells 6.3 cm in radius and 12.7 cm thick. The detectors are mounted on a mechanical structure that allows to easily position the detectors in a wide range of angles and distances from the target. The performances of a single detector, as well as those of the whole apparatus are described. Examples of experimental configurations, used in recent experiments, are presented.

The light charged particles emitted from hot $^{40}\mathrm{Ca}$ compound nuclei, populated at excitation energy ${\mathit{E}}_{\mathit{x}}$=94 MeV and 〈J〉=20.5\ensuremath{\Elzxh} by the reaction 130 MeV $^{16}\mathrm{O}$ on $^{24}\mathrm{Mg}$, have been studied. Energy spectra of protons and alpha particles, measured in coincidence with evaporation residues and with a selection of multiple-alpha chains, have been compared with the predictions of Monte Carlo statistical model calculations. The comparison shows that the level density of hot nuclei with A\ensuremath{\le}40, needed to account for the measured quantities, is well predicted by the Fermi-gas model using a level-density parameter ${\mathit{a}}_{\mathrm{eff}}$=A/8 ${\mathrm{MeV}}^{\mathrm{\ensuremath{-}}1}$ up to excitation energy 〈${\mathit{E}}_{\mathrm{th}}$/A〉\ensuremath{\sim}1.7 MeV. In agreement with theory, light hot nuclei do not show the transition from ${\mathit{a}}_{\mathrm{eff}}$=A/8 ${\mathrm{MeV}}^{\mathrm{\ensuremath{-}}1}$ to ${\mathit{a}}_{\mathrm{eff}}$\ensuremath{\sim}A/13 ${\mathrm{MeV}}^{\mathrm{\ensuremath{-}}1}$ evidenced in the A\ensuremath{\sim}160 mass region for the same range of excitation energies ${\mathit{E}}_{\mathrm{th}}$/A. The analysis of the alpha-particle spectra shows that the effects associated with the angular-momentum-induced deformations depend on the entrance channel characteristics and, in this case, are very small compared with those evidenced in the past for compound nuclei in the region A=50--70.

Abstract Mono-energetic γ-rays of 12 different energies in the energy range 5.4–9 MeV have been used to irradiate 238 U. The results of measurements of angular distributions of photofission fragments are reported and discussed. An analysis assuming penetration barrier function has been performed, and energies of the K -levels have been obtained as well as other nuclear parameters.

This study explored the hole-nesting bird community for two years, in three beech forest stands of central Italy. Our experimental design involved 12 replicated sampling points in each study area for a total of 36 sampling points. Stand characteristics were measured through selected environmental variables (tree diameter, tree density, volume of dead wood, diversity of dead wood and canopy closure), to develop habitat models for describing the factors affecting the abundance of hole-nesting birds. We performed generalized linear models to determine which environmental variables better explained the presence and abundance of hole-nesting birds in the three study areas. The species that showed the highest values of abundance are the Nuthatch, the Blue Tit and the Great Tit. Within the guild of hole-nesting birds there are differences in the selection of suitable trees for nesting, roosting or foraging. Primary cavity nesters (woodpeckers) are mostly related to the presence of large trees, the volume of dead wood and tree height. The presence and abundance of secondary cavity nesters (tits, nuthatches and treecreepers) seem to be mostly influenced by diversity of dead wood. The diversity of dead wood is an important variable that influences the presence and abundance of hole-nesting birds. Maintenance of both living and standing dead wood in forest ecosystems is recommended to increase the effectiveness of conservation actions affecting the hole-nesting birds.

We have measured the high-energy γ-ray spectra from the fusion reactions 130 MeV16O +98Mo and 240 MeV48Ti +64Ni, populating the114Sn and112Sn compound nuclei at the excitation energy of 110 MeV. The comparison of the spectra shows a ~36% enhancement of the α-ray yield in the Giant Dipole Resonance region (E γ > 8 MeV) when the 16 O-induced reaction is considered. This enhancement is interpreted as due to entrance channel effects related to theN/Z asymmetry between the target and the projectile.

Monte Carlo (MC) calculations of the response function of NE213 organic liquid scintillators have been compared with measurements at 2.4 and 13.9 MeV neutron energy, with the purpose of tuning the calculation parameters of detection efficiency vs threshold in the neutron energy range from 1 to 14 MeV. A successful reproduction of the experimental response function has been achieved only enhancing the light yield of recoil protons with respect to the values accepted until now. The experimental depletion of the neutron response function at 13.9 MeV caused by neutron-γ-ray pulse shape discrimination, instead, was not reproduced by MC calculations even after reasonable changes of the related input cross sections.

Alpha particles and protons emitted in the 32S + 74Ge reaction at E = 160, 210, 259, 335 and 435 MeV were measured in coincidence with evaporation residues. The average inverse level-density parameter 〈K〉 for hot evaporation residues with A ∼ 100 was obtained by comparing the slope of the charged-particle spectra with the predictions from a full statistical model calculation. Spectral shapes are well reproduced by calculations using the standard values 〈K〉 = 7.5 MeV, except for alpha particles at the highest bombarding energy, which corresponds to an excitation energy ϵ = 2.2 MeV/nucleon. The present results are compared with other experimental investigations in the A ∼ 100 and A ∼ 160 regions and with predictions from theoretical models. Difficulties in extracting the nuclear temperature from the slope of the particle spectra for A ∼ 100 are discussed.

We report the results of two beam tests performed in July and September 1995 at CERN using silicon microstrip detectors of various types: single sided, double sided with small angle stereo strips, double sided with orthogonal strips, double sided with pads. For the read-out electronics use was made of Preshape32, Premux128 and VA1 chips. The signal to noise ratio and the resolution of the detectors was studied for different incident angles of the incoming particles and for different values of the detector bias voltage. The goal of these tests was to check and improve the performances of the prototypes for the CMS Central Detector.

Light particles spectra in coincidence with fission fragments have been measured for the reaction 187 MeV 37Cl on 120Sn populating 157Ho compound nuclei at the excitation energy Ex = 85 MeV. The experimental neutron pre-scission multiplicity for symmetric splintting is two times larger than the statistical model estimate. The experimental multiplicity is reproduced by calculations in which a fission delay, in agreement with systematics, is introduced. This empirical fission delay produces a sizeable increase, with respect to the standard statistical model estimate, of the survival probability against fission for nuclei with angular momentum around J ∼ h̷. The importance of this effect in the population of superdeformed and hyperdeformed structures in the evaporation residues is discussed.

The giant dipole resonance (GDR) from the decay of excited 156Er nuclei, populated in the reaction 241 MeV 64Ni + 92Zr, has been studied employing a high-resolution 4π γ-ray spectrometer. High-energy γ-ray spectra have been measured in coincidence with both the spectrometer inner ball and the Ge detectors selecting discrete γ-transitions in the residual nuclei 155,154Er. The analysis of the high-energy γ-ray spectra shows that the GDR can be reproduced by a single-lorentzian fit using standard parameters for strength, energy and width, only when a fold k > 10 is required in the inner ball. On the contrary, with lower-fold conditions (k ≤ 10) unrealistic GDR parameters are obtained, mainly due to the presence of light target contaminants. The GDR width determined for k > 10 compares well with systematics and with predictions of adiabatic calculations. The line-shape analysis of the γ-ray spectrum associated with a single evaporation residue (154Er) yields GDR parameters similar to those obtained for the high-fold selected spectra, with the exception of a slightly larger width. No signature is therefore observed for a pre-equilibrium component in the decay of 156Er populated in a nearly symmetric reaction. Nevertheless, differences are evidenced in the comparison of the present spectrum from the 64Ni + 92Zr reaction with earlier results from the 12C + 144Sm asymmetric system.

The energy spectra of α particles emitted in multiple-α decay chains from 59Cu compound nuclei formed in the reaction of 190 MeV 32S on 27Al have been measured. These spectra are sensitive to different regions of the phase space open to the decay of the compound nucleus. A direct test of dynamical effects related to the shape relaxation is obtained by comparing the experimental spectra with results from Monte Carlo statistical model calculations.

Prototype silicon detector modules for the vertex detector of the FINUDA experiment were tested at TRIUMF using pions and protons at 270 and 408 MeV/c in order to study their use for mass discrimination based on energy deposition. The detector modules were constructed using double-sided silicon detectors based on the ALEPH design, read out by VA1 integrated circuits. The test modules and apparatus are described, details of the data analysis are discussed, and the results are presented together with GEANT simulations. Particular attention is given to the detector response for the various particles, with signals ranging from the minimum-ionising pions at 408 MeV/c up to 20 times minimum-ionising for the protons at 270 MeV/c.

The DAωNE project at the Laboratori Nazionali di Frascati (LNF) is an e+e− collider with electron and positron beams accelerated to 510 MeV by a Linac injector. DAωNE is designed to reach a top luminosity L∼ 1033cm−2s−1, that is, to produce ∼4×103 ω(1020)s−1. The hypernuclear research program at DAωNE relies on low-energy kaons, ∼ 16MeV, being produced by ω-meson decays at rest: ω → K−K+ with a B.R.∼49%. In the initial stage, DAωNE will operate at a L∼ 1032cm−2s−1, however the number of ω produced, and the large geometrical acceptance of the FINUDA detector, ∼ 3sr, will allow a strong hypernuclear physics program to be pursued.

Abstract A comparison between silicon microstrip detectors with the same geometry built on 〈1 0 0〉 and 〈1 1 1〉 substrates have been carried out. Three sets of structures— 〈1 0 0〉 low resistivity, 〈1 1 1〉 low resistivity and 〈1 1 1〉 high resistivity—have been electrically characterized. Leakage current, depletion voltage, interstrip capacitance and resistance have been measured before and after neutron irradiation. The samples have been irradiated at five different fluences, up to ≃1.5×10 14 n / cm 2 . The measurements show that the leakage current does not depend, at a given fluence, on crystal orientation and on silicon resistivity. At high irradiation fluences the interstrip resistance decreases for all structures to few tens MΩ . The low resistivity substrates, after type inversion, have a lower depletion voltage than the high resistivity ones. The interstrip capacitance is much less sensitive to radiation effects in 〈1 0 0〉 than in 〈1 1 1〉 structures. We conclude that 〈1 0 0〉 low resistivity sensors show, after irradiation, better performances with respect to standard 〈1 1 1〉 high resistivity devices.

We present results obtained with full-size wedge silicon microstrip detectors bonded to APV6 (Raymond et al., Proceedings of the 3rd Workshop on Electronics for LHC Experiments, CERN/LHCC/97-60) readout chips. We used two identical modules, each consisting of two crystals bonded together. One module was irradiated with 1.7×1014neutrons/cm2. The detectors have been characterized both in the laboratory and by exposing them to a beam of minimum ionizing particles. The results obtained are a good starting point for the evaluation of the performance of the “ensemble” detector plus readout chip in a version very similar to the final production one. We detected the signal from minimum ionizing particles with a signal-to-noise ratio ranging from 9.3 for the irradiated detector up to 20.5 for the non-irradiated detector, provided the parameters of the readout chips are carefully tuned.

A proposal for a pixel-based Level 1 trigger for the Super-LHC is presented. The trigger is based on fast track reconstruction using the full pixel granularity exploiting a readout which connects different layers in specific trigger towers. The trigger will implement the current CMS high level trigger functionality in a novel concept of intelligent detector. A possible layout is discussed and implications on data links are evaluated.

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;This study shows the newest results of a near-series pre-turbo-catalyst (PTC) system reaching lowest emissions for electrified diesel passenger cars to address future emission legislation. The PTC system is developed using a state-of-the-art tool chain containing 1D &amp;amp; 3D simulation approaches and testing near-series exhaust gas aftertreatment systems under real-driving boundary conditions. The innovative concept of a selective catalytic reduction (SCR) PTC and a PTC bypass path solve the challenge of a thermal handshake between PTC and underfloor SCR System as well as the challenge of a particular filter regeneration. The development of adaptive PTC bypass path operation strategies based on exhaust gas and catalyst conditions enables lowest NO&lt;sub&gt;x&lt;/sub&gt; and NH&lt;sub&gt;3&lt;/sub&gt;. Using this concept, zero-impact NO&lt;sub&gt;x&lt;/sub&gt; emissions, that don’t impact cities air quality, can be reached in a wide range of operating scenarios while sustaining full drivability and highest efficiency. Advanced catalyst technologies enable a high emission conversion and lowest secondary emissions. These results have been achieved in the context of the “INES” (“Intelligentes Niedrigstemissionssystem für die Diesel PKW Anwendung”) project, funded by the Bundesministerium für Wirtschaft und Klimaschutz, Ministry for Economic Affairs and Climate Action (BMWK) and addresses research of future mobility requirements.&lt;/div&gt;&lt;/div&gt;

Abstract Cigarette smoking impairs the lung innate immune response making smokers more susceptible to infections and severe symptoms. Dysregulation of cell death is emerging as a key player in chronic inflammatory conditions. We have recently reported that short exposure of human monocyte-derived macrophages (hMDMs) to cigarette smoke extract (CSE) altered the TLR4-dependent response to lipopolysaccharide (LPS). CSE caused inhibition of the MyD88-dependent inflammatory response and activation of TRIF/caspase-8/caspase-1 pathway leading to Gasdermin D (GSDMD) cleavage and increased cell permeability. Herein, we tested the hypothesis that activation of caspase-8 by CSE increased pro-inflammatory cell death of LPS-stimulated macrophages. To this purpose, we measured apoptotic and pyroptotic markers as well as the expression/release of pro-inflammatory mediators in hMDMs exposed to LPS and CSE, alone or in combination, for 6 and 24 h. We show that LPS/CSE-treated hMDMs, but not cells treated with CSE or LPS alone, underwent lytic cell death (LDH release) and displayed apoptotic features (activation of caspase-8 and -3/7, nuclear condensation, and mitochondrial membrane depolarization). Moreover, the negative regulator of caspase-8, coded by CFLAR gene, was downregulated by CSE. Activation of caspase-3 led to Gasdermin E (GSDME) cleavage. Notably, lytic cell death caused the release of the damage-associated molecular patterns (DAMPs) heat shock protein-60 (HSP60) and S100A8/A9. This was accompanied by an impaired inflammatory response resulting in inhibited and delayed release of IL6 and TNF. Of note, increased cleaved caspase-3, higher levels of GSDME and altered expression of cell death-associated genes were found in alveolar macrophages of smoker subjects compared to non-smoking controls. Overall, our findings show that CSE sensitizes human macrophages to cell death by promoting pyroptotic and apoptotic pathways upon encountering LPS. We propose that while the delayed inflammatory response may result in ineffective defenses against infections, the observed cell death associated with DAMP release may contribute to establish chronic inflammation.

Neutron spectra in coincidence with fission fragments have been measured for the 190 MeV $^{28}\mathrm{Si}$${+}^{76}$Ge populating $^{104}\mathrm{Pd}$ compound nucleus at ${\mathit{E}}_{\mathit{x}}$\ensuremath{\sim}133 MeV excitation energy. The extracted prescission multiplicity for symmetric splitting is ${\ensuremath{\nu}}_{\mathrm{pre}}$=1.1\ifmmode\pm\else\textpm\fi{}0.2. The average fission time ${\mathrm{\ensuremath{\tau}}}_{\mathit{F}}$=${6}_{\mathrm{\ensuremath{-}}2}^{+3}$\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}20}$ s is determined, in good agreement with the systematics of Hinde et al. for heavier systems (A\ensuremath{\ge}125 compound nuclei).

This paper describes the main achievements in the development of radiation resistant silicon detectors to be used in the CMS tracker. After a general description of the basic requirements for the operation of large semiconductor systems in the LHC environment, the issue of radiation resistance is discussed in detail. Advantages and disadvantages of the different technological options are presented for comparison. Laboratory measurements and test beam data are used to check the performance of several series of prototypes fabricated by different companies. The expected performance of the final detector modules are presented together with preliminary test beam results on system prototypes.

We present the beam test results of single-sided silicon microstrip detectors, with different substrate resistivities. The effects of radiation damage are studied for a detector irradiated to a fluence of 2.4×1014n/cm2. The detectors are read out with the APV6 chip, which is compatible with the 40MHz LHC clock. The performance of different detectors and readout modes are studied in terms of signal-to-noise ratio and efficiency.

C. Arnault, F. Barone, F. Bellachia, R. Bilhaut, D. Boget, T. Carron, D. Castellazzi, D. Dufournaud, F. Cavalier, R. Chiche, F. Chollet, M. Dehamme, L. Derome, C. Drezen, R. Flaminio, F. Garufi, X. Grave, P. Heusse, O. Lodygenski, F. Marion, L. Massonnet, L. Milano, R. Morand, B. Mours, P. Roudier, V. Sannibale, D. Verkindt, M. Yvert L.A.L. /IN2P3-CNRS et Universite de Paris-Sud, F-91405 Orsay, France I.N.F.N. Sez. di Napoli e Dipartimento di Scienze Fisiche dell’Univ. Federico II, Pad.19, I-80125 Napoli, Italy

Urato, Adam C. MD; Abi-Jaoude, Elia MD, FRCPC; Abramson, John MD, MSc; Alter, Harrison MD, MS; Andrew, Louise B. MD, JD; Antonuccio, David PhD; Bero, Lisa PhD; Biron, Pierre MS, MD; Boylan, Laura S. MD, FAAN; Braillon, Alain MD, PhD; Brophy, James M. MD, PhD; Brownlee, Shannon MSc; Cassels, Alan MPA; Cook-Deegan, Robert MD; Cosgrove, Lisa PhD; De Fiore, Luca; Deyo, Richard A. MD, MPH; Elshaug, Adam MPH, PhD; Farquhar, Cindy FRANZCOG, MPH; Fatovich, Daniel M. MBBS, PhD; Fingerman, Eileen MD; Gérvas, Juan MD, PhD; Gøtzsche, Peter C. DrMedSci; Gracia, Rafael; Heath, Iona MB BChir; Himmelstein, David U. MD, FACP; Hoffman, Jerome R. MA, MD; Järvinen, Teppo MD, PhD; Jureidini, Jon MB, PhD; Kotaska, Andrew MD, FRCSC; Kuehlein, Thomas MD, PhD; Lenzer, Jeanne; Levenstein, Susan MD; Lexchin, Joel MD; Mintzes, Barbara PhD; Naudet, Florian MD, PhD; Niquette, Manon PhD; Orellana Navarrete, Lusy Paulyna MD; Pearson, Cynthia A.; Rail, Geneviève PhD; Roberts, Richard MD, JD; Shah, Naman MD, PhD; Sharav, Vera; Siwek, Jay MD; Topolski, Stefan MD; Tsai, Alexander C. MD, PhD Author Information

Two different experimental methods, based on cosmic rays measurements, have been investigated to calibrate in absolute units the scintillation light detected, near the threshold, at both ends of the long scintillators constituting the External Scintillator Barrel of the FINUDA experiment.The first one is based on the selection of the cosmic rays intercepting also the vertex detectors. The second one takes into account all the cosmic rays detected by the barrel itself.Both methods are shown to be able to evaluate with enough precision an absolute value of the threshold for neutron detection efficiency calculations.

The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R&D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker.

A comparative study on silicon microstrip detectors of the same geometry built on 〈100〉 low resistivity and 〈111〉 high resistivity substrates has been carried out. Leakage current, depletion voltage and interstrip capacitance have been measured before and after irradiation with 34 MeV protons at regular intervals during the beneficial annealing period. The samples were irradiated at four different fluences up to ≃2×1014n/cm2. The measurements after irradiation show that leakage current does not depend on substrate resistivity and crystal orientation. Above type inversion also, the depletion voltage does not depend substantially on the initial resistivity. The interstrip capacitance is damaged both for 〈100〉 and 〈111〉 silicon substrates, even if in the first case the interstrip capacitance increase is lower, as expected from the known difference in charge trapping effects. The results of this work are compared with previous measurements performed on identical structures irradiated with neutrons.

The CMS silicon tracker [1], requires the assembly of about 16,000 silicon detector modules with reproducible quality. In order to ensure proper module assembly, an automated system has been developed at CERN, based on a high-precision robotic positioning machine. This project has successfully demonstrated the feasibility of high quality and high throughput module assembly. Four assembly centers are now being installed in Europe at Bari, Perugia, Lyon, Brussels and at Padova in addition, as backup. Two assembly centers in USA at Fermilab share the assembly task. All centers will have identical robotic positioning machines in order to assure uniform high quality module construction.

A complete prototype of the CMS tracker read-out and control system has been built using components as close as possible to the final design. It is based on an amplifier and analogue pipeline memory chip (APV), analogue optical links transmitting at 40Ms/s and a VME mounted digitisation and data handling board (FED-PMC), supplemented by a control architecture based on FECs which set and monitor the components of the entire system. This system has been successfully operated for the first time under LHC like beam conditions in a 25ns structured beam provided by the SPS at CERN. The objective was primarily to test the synchronisation and pile-up effects in a high trigger rate environment and to examine the many issues involved in operating a complete readout and control system.

Neutron spectra in coincidence with fission fragments have been measured for the 115 MeV 16O + 144Sm and 270 MeV 60Ni + 100Mo reactions, populating 160Yb compound nucleus at Ex∼75 MeV excitations energy. The extracted pre-scission multiplicity for the 60Ni + 100Mo reaction is substantially larger than the statistical model prediction, demonstrating clearly that dynamical effects dominate even at low excitation energy.

The behaviour of the leakage current, interstrip resistance and capacitance have been studied on silicon microstrip detectors during an annealing period equivalent to ≃108min at room temperature, after 34MeV proton irradiation. A comparison between samples of the same geometry built on 〈100〉 and 〈111〉 substrates with different resistivity has been carried out. The samples were irradiated at 4 different fluences up to 1×1014p/cm2. After the irradiation the measurements were performed at room temperature and after heating the samples at 60°C, 80°C and 120°C to cover the complete annealing curve. The leakage current shows the same annealing behaviour typical of a simple diode. The interstrip resistance measured at full depletion voltage (Vdep) decreases in all structures, going down to few tens of MΩ at the highest fluence. It remains practically constant during the annealing period. The interstrip capacitance (at Vdep) varies during the annealing period with the same behaviour in both substrates and for all the fluence values: it decreases during the annealing at room temperature, reaching a minimum value, and increases after each heat treatment. Bistable defects seem to contribute to the interstrip capacitance variation.

Abstract The behaviour of leakage current and depletion voltage have been studied on silicon diodes of different resistivity during the full annealing period after 34 MeV proton irradiation. After the irradiation the measurements were performed after heating the samples to cover the complete annealing curve. The hardness factor was estimated through the measurement of the diode leakage current as a function of annealing time. The diode leakage current and depletion voltage values show a significant decrease as a function of time after heating at high temperatures. This effect is typical of bistable defects. The defect can be activated by illumination, forward bias and further heating. The average time constant of the de-activation process has been found to be 4 h , independently of the activation process.

Capacitance, resistance and current measurements were carried out on single-sided, n+ on n silicon strip detectors. We studied the type inversion after irradiating the detectors with neutron fluences up to 8.3×1013neutron/cm2. To understand the macroscopic irradiation effects, a SPICE model of the detector was developed. Simulating the capacitance measurements, we were able to reproduce the measured frequency dependence of the relevant capacitances, both for non-irradiated and for irradiated detectors.

The FINUDA experiment will start data taking in 1997 to study hypernuclear physics by a large acceptance, high resolution magnetic spectrometer at DAΦNE, the Frascati φ-factory. Physics motivations and goals besides the expected performances are described.

A prototype unit consisting of two organic scintillator detectors (NE102A and NE213) used to detect neutrons up to 400 MeV is described. Each element has a volume of 100 × 10 × 10 cm3 with the major side transverse to the incident neutron beam. The detectors were calibrated in the energy range 54–360 MeV with neutrons from the np å np reaction. The measured detection efficiencies (4–10%) are compared with the predictions of a Monte Carlo code for three neutron detection thresholds: 2, 6 and 16 MeVee. The timing performances of the neutron unit are: 740 and 850 ps for the NE102A and NE213, respectively.

Neutrons emitted by targetlike fragments after the inelastic reactions of 154 MeV $^{32}\mathrm{S}$ on $^{100}\mathrm{Mo}$ have been measured. Neutron energy spectra and multiplicities have been derived as a function of the dissipated energy for targetlike fragment mass bins ${A}_{\mathrm{TL}}$=96--98, 101--103, and 104--106 and have been compared with the results of a Monte Carlo simulation which performs statistical model calculations of the targetlike fragment decay, with different assumptions on the partition of the excitation energy between the reaction partners. The partition following an equal temperature hypothesis better describes the experimental data but a sizable influence of the exit channel is found on the experimental neutron multiplicity.

The vertex detector of the FINUDA experiment is described, and results are presented from tests of prototype modules in mixed pion/proton beams at both 408 and 270 MeV/c.

The giant dipole resonance (GDR) from the decay of excited 156Er nuclei populated in the reaction 64Ni + 92Zr at 241 MeV has been studied by using the GASP spectrometer. High-energy γ-rays spectra have been obtained in coincidence with the 80 elements of the GASP inner ball and with discrete transitions in the residual nuclei 155,154Er. GDR parameters extracted from the high-energy γ-rays spectra in coincidence with low-energy γ-ray folk k>10 are in good agreement with systematics as well as with predictions from adiabatic calculations. No signature for entrance channel effects in the decay of 156Er was therefore observed from this lineshape analysis of the high-energy γ-rays spectra in contrast with the case of the 164Yb nucleus.

The \ensuremath{\gamma} decay of energy relaxed fragments has been studied as a function of the mass asymmetry in the exit channel for the $^{32}$S${+\mathrm{}}^{58}$Ni reaction at 143 MeV. \ensuremath{\gamma}-multiplicity and \ensuremath{\gamma}-anisotropy data as well as 〈Q〉 values from fragment inclusive measurements show the differences between the deep-inelastic and the ``fission-like'' regimes. The role of the deformation in the symmetric splitting is outlined for medium mass (A\ensuremath{\sim}100) composite systems.

The CMS Silicon tracker consists of 70m2 of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors.

The neutron emission from the targetlike fragments (TLF) of the inelastic reactions of 157 MeV $^{32}\mathrm{S}$ on $^{64}\mathrm{Ni}$ has been measured. Neutron energy spectra and multiplicities have been extracted as a function of the dissipated energy for six targetlike fragments mass gates between A=56 and A=70. The comparison between the data and the results of a Monte Carlo simulation based on statistical model calculations with different assumptions on the excitation energy sharing between the reaction partners evidences a dependence from the net mass flow of the evolution of the excitation energy ratios with the energy loss.

For the construction of the silicon microstrip detectors for the Tracker of the CMS experiment, two different substrate choices were investigated: A high-resistivity (6 k cm) substrate with (111) crystalorientation and a low-resistivity (2k cm) one with (100) crystalorientation. The interstrip and backplane capacitances were measured before and after the exposure to radiation in a range of strip pitches from 60 μm to 240 μm and for values of the width-over-pitch ratio between 0.1 and 0.5.

Abstract A large quantity of silicon microstrip detectors is foreseen to be used as part of the CMS tracker. A specific research and development program has been carried out with the aim of defining layouts and technological solutions suitable for the use of silicon detectors in high radiation environment. Results presented here summarise this work on many research areas such as techniques for device manufacturing, pre- and post-irradiation electrical characterization, silicon bulk defects analysis and simulations, system performance analytical calculations and simulations and test beam analysis. As a result of this work we have chosen to use single-sided, AC-coupled, poly silicon biased, 300 μm thick, p + on n substrate detectors. We feel confident that these devices will match the required performances for the CMS tracker provided they can be operated at bias voltages as high as 500 V. Such high-voltage devices have been succesfully manufactured and we are now concentrating our efforts in enhancing yield and reliability.

The breakdown performance of CMS barrelmodule prototype detectors and test devices with single and multi-guard structures were studied before and after neutron irradiation up to 2·1014 1 MeV equivalent neutrons. Before irradiation avalanche breakdown occurred at the guard ring implant edges. We measured 100–300 V higher breakdown voltage values for the devices with multi-guard than for devices with single-guard ring. After irradiation and type inversion the breakdown was smoother than before irradiation and the breakdown voltage value increased to 500–600 V for most of the devices.

The reactions induced by 143 MeV32S on58Ni have been studied detecting discrete γ-rays in coincidence with projectile-like fragments (PLF). Information on PLF excitation probability and sequential decay of target-like fragments (TLF) has been obtained. For the28Si+62Zn outgoing channel at small energy loss (¦Q¦<20 MeV), both PLF and TLF data indicate that thermal equilibrium is not attained. The hypothesis of an equal excitation energy partition between the two reaction fragments does not describe properly experimental TLF data. A dependence of PLF excitation probability on the outgoing channel is found for the two final channels32S+58Ni and28Si+62Zn. The values of the spin alignment parameterP zz, derived for PLF and TLF from measurements ofγ-rays anisotropy, are in disagreement with the expectations of the transport theory for dissipative collisions.

This paper describes the Silicon microstrip Tracker of the CMS experiment at LHC. It consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 10 000 single-sided equivalent modules have to be built, each one carrying two daisy-chained silicon detectors and their front-end electronics. Back-to-back modules are used to read-out the radial coordinate. The tracker will be operated in an environment kept at a temperature of T=−10°C to minimize the Si sensors radiation damage. Heavily irradiated detectors will be safely operated due to the high-voltage capability of the sensors. Full-size mechanical prototypes have been built to check the system aspects before starting the construction.

The inner portion of the CMS microstrip Tracker consists of 3540 silicon detector modules; its construction has been under full responsibility of seven INFN (Istituto Nazionale di Fisica Nucleare) and University laboratories in Italy. In this note procedures and strategies, which were developed and perfected to qualify the Tracker Inner Barrel and Inner Disks modules for installation, are described. In particular the tests required to select highly reliable detector modules are illustrated and a summary of the results from the full Inner Tracker module test is presented. 1) INFN sez. di Catania and Universita di Catania, Italy 2) INFN sez. di Perugia and Universita di Perugia, Italy 3) INFN sez. di Pisa and Scuola Normale Superiore di Pisa, Italy 4) INFN sez. di Pisa and Universita di Pisa, Italy 5) INFN sez. di Pisa, Italy 6) INFN sez. di Torino and Universita di Torino, Italy 7) INFN sez. di Torino, Italy 8) INFN sez. di Firenze, Italy 9) INFN sez. di Bari and Dipartimento Interateneo di Fisica di Bari, Italy 10) INFN sez. di Bari, Italy 11) INFN sez. di Padova, Italy 12) INFN sez. di Firenze and Universita di Firenze, Italy 13) INFN sez. di Padova and Universita di Padova, Italy 14) INFN sez. di Perugia, Italy a) On leave from ISS, Bucharest, Romania b) On leave from IFIN-HH, Bucharest, Romania c) Corresponding Author

The FINUDA experiment will start data taking in 1997 to study hypernuclear physics by a large acceptance. high resolution magnetic spectrometer at DAΦNE, the Frascati o-factory. Physics motivations and goals besides the expected performances are described.

Abstract FINUDA is a large acceptance, high resolution magnetic spectrometer dedicated to hypernuclear physics. The experiment is in an advanced stage of construction and will run in 1997 at DAΦNE, the Frascati o-Factory. Motivations, physics goals and expected performance are illustrated.

Abstract A large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300 μ m thick, p + on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2×10 14  n/cm 2 . The detector performances do not significantly change if the detectors are biased well above the depletion voltage. S / N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500 V).

We report the results of test beams performed at CERN using irradiated microstrip silicon detectors. The detectors were single- and double-sided devices, produced by different manufacturers and irradiated with neutrons at various fluences up to 3.6 × 1013 n/cm2. Signal-to-noise ratio, resolution and efficiency were studied for different values of the incidence angle, of the detector temperature and of the read-out pitch, as a function of the detector bias voltage. The goal of these tests was to optimize the design of the final prototypes for the CMS Silicon Strip Tracker.

A parallel scalable Data Acquisition based on VME, has been developed to be used in the FINUDA experiment, scheduled to run at the DA/spl Phi/NE machine at Frascati in 1998. The acquisition software runs on embedded RTPC 8067 processors using the LynxOS operating system. The read-out of event fragments is coordinated by a suitable trigger supervisor. Data read by different controllers are transported via dedicated bus to a Global Event Builder running on a PowerPC machine. Commands from and to VME processors are sent via socket based network protocols. The Online Monitor, froot, is based on an object oriented approach in the framework of the ROOT package.

An important tool for the discovery of new physics at LHC is the design of a low level trigger with an high power of background rejection. The contribution of pixel detector to the lowest level trigger at CMS is studied focusing on low-energy jet identification, matching the information from calorimeters and pixel detector. In addition, primary vertex algorithms are investigated. The performances are evaluated in terms of, respectively, QCD rejection and multihadronic jets final states efficiency.

The performance of a prototype module of a calorimeter for the measurement of the neutron multiplicity associated with reverse-kinematic heavy-ion reactions has been tested with 14 MeV neutrons. Its response was well reproduced by Monte Carlo (MC) calculations. Utilizing the experimental response, the detection of “groups” of monokinetic neutrons with known multiplicity has been simulated. These simulated results compare favourably with the MC calculations and show little sensitivity to the details of the response function at the lowest amplitudes, where possible noise could arise. A new neutron γ-ray discrimination technique has been successfully used to identify neutrons from 50 and 80 MeV/nucleon heavy-ion induced reactions at the Bevalac.

Abstract A new fast neutron high multiplicity detector is proposed based on the measurement of the total light yielded by the neutrons in a plastic scintillator. Its performance is simulated by Monte Carlo methods and compared to existing neutron multiplicity detectors. A cost effective design for reverse kinematics heavy ion reactions is presented and connected problems discussed.

Inclusive neutron spectra from the decay of $^{156}\mathrm{Er}$ compound nucleus populated at ${\mathit{E}}_{\mathit{x}}$=47 MeV excitation energy by the $^{12}\mathrm{C}$${+}^{144}$Sm and $^{64}\mathrm{Ni}$${+}^{92}$Zr reactions have been measured. The neutron spectra from the $^{64}\mathrm{induced}$ reaction are strongly contaminated by other reactions different from fusion evaporation so that inclusive spectra cannot be used to test nonstatistical or entrance channel effects in the compound nucleus decay.

We present beam test results on AC-coupled, single-sided, n+-on-n type silicon microstrip detectors. We have tested the detectors before and after irradiation at a fluence of 8.3×1013 n/cm2, at different temperatures and bias voltages. Signal-to-noise ratio, spatial resolution, charge collection and overall efficiency have been measured.

We report selected results of laboratory measurements and beam tests of heavily irradiated microstrip silicon detectors. The detectors were single-sided devices, produced by different manufacturers and irradiated with different sources, for several total ionizing doses and fluences up to 4 /spl times/10/sup 14/ 1-MeV-equivalent neutrons per cm/sup 2/. Strip resistance and capacitance, detector leakage currents and breakdown performance were measured before and after irradiations. Signal-to-noise ratio and detector efficiency were studied in beam tests, for different values of the detector temperature and of the read-out pitch, as a function of the detector bias voltage. The goal of these test is to optimise the design of the final prototypes for the Silicon Strip Tracker of the CMS experiment at the CERN LHC collider.

Abstract The new silicon tracker layout (V4) is presented. The system aspects of the construction are discussed together with the expected tracking performance. Because of the high radiation environment in which the detectors will operate, particular care has been devoted to the study of the characteristics of heavily irradiated detectors. This includes studies on performance (charge collection, cluster size, resolution, efficiency) as a function of the bias voltage, integrated fluence, incidence angle and temperature.

The CMS silicon strip tracker involves about 70 m2 of instrumented silicon, with approximately 18500 microstrip detectors read out by 5 × 106 electronics channels. It has to satisfy a set of stringent requirements imposed by the environment and by the physics expected at the LHC: low cell occupancy and good resolution, radiation hardness aided by adequate cooling, low mass combined with high stability. These conditions have been incorporated in a highly modular design of the detector modules and their support structures, chosen to facilitate construction and to allow for easy assembly and maintenance.

The paper describes the Silicon Tracking System of the Compact Muon Solenoid (CMS) experiment that is foreseen to collect events from p–p collision at the Ecm=14 TeV at the CERN future Large Hadron Collider (LHC). The proposed system consists of four layers of silicon microstrip detectors placed between the two inner layers of the pixel detector and the outer microstrip gas chamber system. The barrel part covers the η region up to 1.8, instrumenting the central radial region between 20 and 50 cm. The forward–backward disks extend the coverage up to η=2.6. This paper will review the main characteristics and performances of the system, the actual status of the R&D activities that we are carrying on, and the status of the milestones we have to fulfill in view of the Technical Design Report expected at the end of the year.

This paper describes the silicon microstrip tracker of the CMS experiment at the future LHC. The silicon tracker consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 6500 modules will have to be built, each one carrying two daisy-chained silicon sensors and their front-end electronics. The modules have been designed to be as simple and robust as possible. Radiation damage in the silicon sensors is minimized by cooling the whole system down to -10°C. Safe operation after heavy irradiation will be possible due to the high-voltage capability of the sensors. We expect the sensors to have a signal-to-noise ratio of 10 at the end of 10years of LHC running, which still gives an efficiency of almost 100%.

Neutrons emitted by targetlike fragments after the inelastic reactions of 154 MeV {sup 32}S on {sup 100}Mo have been measured. Neutron energy spectra and multiplicities have been derived as a function of the dissipated energy for targetlike fragment mass bins {ital A}{sub TL}=96--98, 101--103, and 104--106 and have been compared with the results of a Monte Carlo simulation which performs statistical model calculations of the targetlike fragment decay, with different assumptions on the partition of the excitation energy between the reaction partners. The partition following an equal temperature hypothesis better describes the experimental data but a sizable influence of the exit channel is found on the experimental neutron multiplicity.

The deep-inelastic reaction induced by 143 MeV32S on58Ni have been studied detecting projectile-like fragments (PLF) in coincidence withγ-rays in NaI(TI) scintillators. γ-ray multiplicity and anisotropy have been derived for Zplf=14, 15 as a function of energy loss and/or γ-energy. The information obtained are compared with a discrete γ-line study of the same reaction. The effect of the exit channel selection (ejectileZ, energy loss,E γ) on the γ-observables is discussed in connection with the evidence of a strong PLF γ-emission.