Cathode strip chamber for CMS ME1/1 endcap muon station

Seventy-six serial ME1/1 cathode strip chambers have been produced in Dubna. These chambers are the coordinate detectors of the first muon station of the CMS detector at CERN. This paper describes the design of the chamber, its main mechanical parameters, and the results of the cosmic ray test. The text was submitted by the authors in English.     

Electromagnetic secondaries and punch-through effects in the CMS ME1/1

The aim of this work is to estimate the shower leakage from the CMS Endcap Hadron calorimeter (HE) due to electromagnetic secondaries and punch-through in the region of the ME1/1 Forward Muon Station. Two configurations are considered: with and without the CMS Endcap Electromagnetic calorimeter (EE). The experimental data have been taken during the combined beam test of CMS subdetectors (HE, ME, RPC, DT) at the CERN H2 beam facility in 2004. Serial CSC chambers (ready for installation in CMS) fully equipped with readout electronics have been exposed. Simulation of a beam test setup has been performed using the GEANT4-based simulation software package OSCAR. The text was submitted by the authors in English.     

The Bland–Altman analysis: Does it have a role in assessing radiation dosimeter performance relative to an established standard?

Bland–Altman analysis is used to compare two different methods of measurement and to determine whether a new method of measurement may replace an existing accepted ‘gold standard’ method. In this work, Bland–Altman analysis has been applied to radiation dosimetry to compare the PTW Markus and Roos parallel plate ionisation chambers and a PTW PinPoint chamber against a Farmer type ionisation chamber which is accepted as the gold standard for radiation dosimetry in the clinic. Depth doses for low energy x-rays beams with energies of 50, 75 and 100 kVp were measured using each of the ionisation chambers. Depth doses were also calculated by interpolation of the data in the British Journal of Radiology (BJR) Report 25. From the Bland–Altman analysis, the mean dose difference between the two parallel plate chambers and the Farmer chambers was 1% over the range of depths measured. The PinPoint chamber gave significant dose differences compared to the Farmer chamber. There were also differences of up to 12% between the BJR Report 25 depth doses and the measured data. For the Bland–Altman plots, the lines representing the limits of agreement were selected to be a particular percentage agreement e.g. 1 or 2%, instead of being based on the standard deviation (σ) of the differences. The Bland–Altman statistical analysis is a powerful tool for making comparisons of ionisation chambers with an ionisation chamber that has been accepted as a ‘gold standard’. Therefore we conclude that Bland–Altman analysis does have a role in assessing radiation dosimeter performance relative to an established standard.     

New determination of the astrophysical S factor SE1 of the 12C(alpha,gamma)16O reaction

A new measurement of the beta-delayed alpha decay of 16N has been performed using a set of high efficiency ionization chambers. Sources were made by implantation of a 16N beam, yielding very clean alpha spectra down to energies as low as 400 keV. Our data are in good agreement with earlier results. For the S factor S(E1), we obtain a value of 74 +/- 21 keV b. In spite of improvements in the measurement, the error in S(E1) remains relatively large because of the correlations among the fit parameters and the uncertainties inherent to the extrapolation.     

THE PERFORMANCE TEST OF 1m×1m DRIFT CHAMBERS WITH ON-LINE MICROCOMPUTER

The performance of a 1m×1m drift chamber system have been measured with on-line microcomputer using comic rays. The time resolution is 4.26 ns. The spatial resolution is 132 μm and the efficiency is above 96%. The experimental set-up include five 1m×1m adjustable field drift chambers, scintillation counter trigger system, readout electronics and a TRS-80 microcomputer. The data acquisition and processing have been done with on-line microcomputer and off-line data analysis.     

On helicity conservation in the reaction π−p → A1p at 4.45 GeV/c

Helicity conservation in the reaction π^? p → pA₁ at 4.45 GeV/c has been studied using 50 cm and 55 cm liquid hydrogen bubble chambers. In the Jackson and the helicity frames the dependence of the ? matrix elements on the four-momentum transfer squared to the proton (t) for A₁ maximum decay has been calculated. The obtained data are in a good agreement with t-channel helicity conservation. The t-channel dependence of the ? matrix elements in the mentioned frames is in good agreement with that calculated using the Regge π-pole exchange model (it is suggested that the A₁ maximum nature is explained by a kinematical effect of the Deck type).     

Recovery of LHCb Detector Muon Chambers for Malter Effect Elimination

A method is presented for restoring the performance of gas discharge detectors wherein a spontaneous self-sustaining current, i.e., Malter effect, occurs. A successful practical implementation of the method is demonstrated by the example of recovery of operability for multiwire proportional chambers used in the muon detector of the LHCb experiment carried out at the Large Hadron Collider. Four proportional chambers wherein Malter currents regularly occur during the experiment were subjected to high-voltage discharge training in the working gas mixture of 40% Ar + 55% CO2 + 5% CF4 with 2% of oxygen added. It is shown that, with addition of oxygen, the recovery of the proportional chambers occurs tens of times faster in compare to the training in the working gas mixture. The reconstructed chambers were installed in the LHCb muon detector and have been working in a collider beam experiment for more than two years already.     

Reconstruction of Charged-Particle Trajectories in Multiwire Proportional Chambers at the BM@N Experiment

The algorithm for track reconstruction in multiwire proportional chambers (MWPCs) of the BM@N (Baryonic Matter at Nuclotron) experiment is described. The beam tracks before the interaction with the target and trajectories of charged particles after the interaction are reconstructed using Nuclotron experimental data with deuteron and carbon beams colliding with the carbon and copper targets. Trajectories are extrapolated to the interaction point and to drift chambers. The efficiencies of MWPCs have been obtained. Beam parameters (transverse dimensions and angular spread) have been measured as well.     

Dilated Minute Chambers in Laryngeal Vocal Fold Polyps: Histopathological and Ultrastructural Features

In Reinke's space of human vocal fold, type III collagen forms a three dimensional network and this contains numerous minute chambers in between these fibers. These compartments are occupied by glycosaminoglycans and glycoproteins. In laryngeal fold lesions, such as Reinke's edema and vocal fold polyps, proteoglycan (PG)/hyaluronic acid (HA) components of extracellular matrix increased. We investigated the size and quantity of the minute chambers within Reinke's space, filled with PG/HA with the aid of transmission electron microscopy. Eight vocal fold polyps and 10 mucosal biopsies (as control group) were all evaluated by light microscopy and electron microscopy. We detected that PG/HA in extracellular matrix had been increased in vocal fold lesions when compared with control group, by Alcian Blue-pH 2.5 stain. The mean volume of the chambers in Reinke's space of normal larynx was measured as 0.040233 µm² whereas the mean volume of these chambers in vocal fold polyps was measured as 6.420221 µm². The difference between the volumes of these chambers in vocal fold polyps and in control group was statistically significant (P = 0.001). Within these chambers PG/HA were found and PG/HA filling these chambers were increased in vocal fold polyps. We think proteoglycan and glycosaminoglycans, especially HA, play an important role in determining biochemical properties of vocal fold lesions.     

Assessment of a simplified experimental procedure to evaluate impact sound reduction of floor coverings

The impact noise reduction provided by floor coverings is usually obtained in laboratory, using the methodology described in the standard EN ISO 140-8, which requires the use of standard acoustic chambers. The construction of such chambers, following the requirements described in the EN ISO 140-1, implies a significant investment, and therefore only a limited number exists in each country. Alternatives to these standard methodologies, that allow a sufficiently accurate evaluation and require lower resources, have been interesting many researchers and manufacturers. In this paper, one such strategy is discussed, where a reduced sized slab is used to determine the noise reduction provided by floor coverings, following the procedure described in the ISO/CD 16251-1 technical document. Several resilient coverings, floating floors and floating slabs are tested and the results are compared with those obtained using the procedures described in the standards EN ISO 140-8 and EN ISO 717-2.     

束流位置监测系统的研制及其在国家同步辐射实验室二期工程中的应用

 介绍一种储存环束流位置监测系统的标定装置。这套标定装置是为NSRL二期工程储存环注入段真空盒改造而研制的。系统的标定精度达±0.01mm。该装置已用于新增注入段真空管的束流位置探测器的定标，获得了探头定标值，并根据其拟合和计算结果对注入段真空管进行了筛选，被选中的真空管已装入储存环注入段。     

A retrospective view on “3-dimensional radiation in absorbing, emitting and scattering media using discrete-ordinates approximation” by J.S. Truelove

Discrete-ordinates (DO) approximations to the radiative transfer equation in three-dimensional enclosures have extensively been used during the last three decades. The 1988 paper by Truelove [1] is one of the pioneering works in this field wherein traditional DO formulations were adapted to radiative transfer problems, and has impacted both the science and the technology related to large-scale combustion chambers since it was published. The following is a short introduction to this seminal JQSRT paper.     

Commissioning of the New sMDT Monitored Drift Tube Detectors for the Phase-1 Upgrade of the ATLAS Muon Spectrometer

Physics of Atomic Nuclei - The Muon Drift Tube (MDT) chambers provide very precise and reliable muon tracking and momentum measurement in the ATLAS muon spectrometer. Already in Run 2 of the LHC...     

Optimization methodology for electrospray evaporative cooling chambers

Electrospray evaporative cooling (ESEC) has been investigated as the potential thermal management solution for future electronics. However, the optimal heat transfer performance of ESEC chambers has not yet been thoroughly examined. This paper investigates optimal heat transfer performance of ESEC chambers with different geometry types. The geometry types affect the ESEC chambers' heat transfer performance in different ways. Although increasing the quantity of the micronozzles and the spacing between them does not improve the steady state heat transfer performance, a higher quantity of micronozzles with increased spacing noticeably enhances the transient cooling rate. Additionally, certain practical design issues are discussed.     

马铁菊头蝠声道声学特性的数值分析

采用有限元数值计算得到了马铁菊头蝠声道内部的声场分布,给出了马铁菊头蝠声道内几种特殊的腔体结构在蝙蝠发声过程中的作用。通过微型CT扫描并经过三维重构得到了马铁菊头蝠声道的三维立体模型用于有限元数值计算,通过在声门处放置单位声源计算得到了整个声道内部以及鼻孔周围的声压分布。结果表明,马铁菊头蝠声道包含了鼻腔结构后声波在声门上方的声压幅度明显大于不含鼻腔结构的情况,从传输曲线来看,声门上方鼻腔的存在使得系统对声波传输在二次谐波频率处呈现低阻抗效果,同时鼻腔的改变还可影响二次谐波的位置。而声门下方的气管空腔主要影响声波的背向转播,声门下方的气管空腔的存在可明显降低蝙蝠发声时声场在声道声门下方的声压幅度,同时抑制声音背向传播时二次谐波成分的强度。      

Recent progress in subatomic particle detection technology

Particle detection technologies have been largely advanced in ,boratory over the past decade. A neutron sphere was built to detect the decay neutron emitted from the implanted unstable nu eleus, whereas a multi-neutron correlation spectrometer was implemented to detect the forward moving neutrons resulting from breakup reactions. Charged particle telescopes are now equipped with double sided Silicon strip detectors which have excellent energy and position resolutions. Large size gas chambers, such as resistive plate chambers, have been developed in order to achieve high Derformances related to timing or position measurements. The advances of these technologies con tribute substantially to such large science project, as LHC-CMS, and to the experiments with the radioactive nucleus beams.     

Finiteness of the triple gauge-ghost vertices in $${{\mathcal {N}}}=1$$ supersymmetric gauge theories: the two-loop verification

The European Physical Journal C - Dielectric breakdown strength is one of the critical performance metrics for pure gases and gas mixtures used in large, high pressure gas time projection chambers....     

Near-infrared storage ring free electron laser experiments at AIST

The development of free electron lasers (FELs) with a compact storage ring NIJI-IV in the near- and middle-infrared regions has been advanced at the National Institute of Advanced Industrial Science and Technology. The optical klystron ETLOK-III was installed in one of the long straight sections of the NIJI-IV, and spontaneous emission spectra were observed in the visible and near-infrared regions. Optical cavity chambers for infrared FELs were installed this February, and it was confirmed that the vibration amplitude of the optical cavity chambers was below 0.5 μm in an optical beam axis. FEL experiments in the near-infrared region will be performed this winter.     

Manufacturing and qualification of UHV chambers

Vacuum chambers or vacuum components that are widespread in research and in industry must fulfill high degrees of cleanliness, especially if they are required for ultra-high-vacuum (UHV) applications. It is shown that common techniques that are used for manufacturing and testing of pressure containers and of related items are often not sufficient for UHV requirements. Outstanding vacuum chambers and components are described, which have been fabricated for actual research applications. The requirements for the design, manufacturing and performance of such systems will be displayed, providing support for adequate specification. PACS 07.30.Kf; 07.30.Hd     

PSII系统中微波ECR等离子体的朗缪尔探针诊断

用朗缪尔探针对一个新颖的双谐振腔多功能PSII系统的微波ECR等离子体进行了诊断,得出了会切场中工作气体压强和微波功率对等离子体密度和电子温度的影响,及真空室内等离子体的分布。