On the electromagnetic energy resolution of Cherenkov-fiber calorimeters

Electromagnetic calorimeters which sample the Cherenkov radiation of shower particles in optical fibers operate in a markedly different manner from calorimeters which rely on the dE/dx of shower particles. The well-understood physics of electromagnetic shower development is applied to the case of Cherenkov-fiber calorimetry (also known as quartz fiber calorimetry) and the results of systematically performed studies are considered in detail to derive an understanding of the critical parameters involved in energy measurement using such calorimeters. A quantitative parameterization of Cherenkov-fiber calorimetry electromagnetic energy resolution is proposed and compared with existing experimental results

CMS Forward-Backward MSGC milestone

The CMS MF1 milestone was set in order to evaluate system aspects of the CMS forward-backward MSGC tracker, to check the design and feasibility of mass production and to set up assembly and test procedures. We describe the construction and the experience gained with the operation of a system of 38 MSGC detectors assembled in six multi-substrate detector modules corresponding to the geometry of the forward-backward MSGC tracker in CMS. These modules were equipped with MSGCs mounted side by side, forming a continuous detector surface of about 0.2 m2. Different designs were tried for these modules. The problems encountered are presented with the proposed solutions. Operation conditions for the 38 MSGCs are reported from an exposure to a muon beam at the CERN SPS. Gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with the detection efficiency, the spatial resolution, alignment and edge studies

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Quenching Statistics of Silicon Single Photon Avalanche Diodes

The statistical behavior of silicon-based single-photon-avalanche-diodes (SPADs) is investigated by using self-consistent 3-D Monte Carlo simulations. The coupling of Poisson and Boltzmann transport equations allows us to go beyond the analysis of avalanche breakdown and its timing and to extend the investigation to the quenching of the photodetector circuit. We find out that the quenching of SPADs is probabilistic and strongly depends on the surrounding circuit, in particular on the so-called quenching resistance. Independently of the SPAD deadtime, it appears that the extinction time needed to suppress any avalanche event may vary over a very large range

Avalanche breakdown and quenching in Ge SPAD using 3D Monte Carlo simulation

International audienc

Molecular characterization of new selective peroxisome proliferator–activated receptor {gamma} modulators with angiotensin receptor blocking activity

Selective peroxisome proliferator–activated receptor (PPAR) {gamma} modulation is a new pharmacological approach that, based on selective receptor-cofactor interactions and target gene regulation, should result in potent insulin sensitization in the absence of PPAR{gamma}-mediated adverse effects. Here, we characterize two angiotensin receptor blockers (ARBs), telmisartan and irbesartan, as new selective PPAR modulators (SPPARMs). Analysis of PPAR{gamma} protein conformation using protease protection showed that telmisartan directly interacts with the receptor, producing a distinct conformational change compared with a glitazone. Glutathione S-transferase pull-down and fluorescence resonance energy transfer assays revealed selective cofactor binding by the ARBs compared with glitazones with an attenuated release of the nuclear receptor corepressor and absence of transcriptional intermediary factor 2 recruitment by ARBs. Consistently, selective cofactor binding resulted in differential gene expression profiles in adipocytes (ARB versus glitazone treated) assessed by oligo microarray analysis. Finally, telmisartan improved insulin sensitivity in diet-induced obese mice in the absence of weight gain. The present study identifies two ARBs as new SPPARMs. SPPARM activity by ARBs could retain the metabolic efficacy of PPAR{gamma} activation with reduction in adverse effects exerting in parallel AT1 receptor blockade. This may provide a new therapeutic option for better cardiovascular risk management in metabolic diseases and may initiate the development of new classes of drugs combining potent antihypertensive and antidiabetic actions

Molecular characterization of new selective peroxisome proliferator–activated receptor {gamma} modulators with angiotensin receptor blocking activity

Selective peroxisome proliferator–activated receptor (PPAR) {gamma} modulation is a new pharmacological approach that, based on selective receptor-cofactor interactions and target gene regulation, should result in potent insulin sensitization in the absence of PPAR{gamma}-mediated adverse effects. Here, we characterize two angiotensin receptor blockers (ARBs), telmisartan and irbesartan, as new selective PPAR modulators (SPPARMs). Analysis of PPAR{gamma} protein conformation using protease protection showed that telmisartan directly interacts with the receptor, producing a distinct conformational change compared with a glitazone. Glutathione S-transferase pull-down and fluorescence resonance energy transfer assays revealed selective cofactor binding by the ARBs compared with glitazones with an attenuated release of the nuclear receptor corepressor and absence of transcriptional intermediary factor 2 recruitment by ARBs. Consistently, selective cofactor binding resulted in differential gene expression profiles in adipocytes (ARB versus glitazone treated) assessed by oligo microarray analysis. Finally, telmisartan improved insulin sensitivity in diet-induced obese mice in the absence of weight gain. The present study identifies two ARBs as new SPPARMs. SPPARM activity by ARBs could retain the metabolic efficacy of PPAR{gamma} activation with reduction in adverse effects exerting in parallel AT1 receptor blockade. This may provide a new therapeutic option for better cardiovascular risk management in metabolic diseases and may initiate the development of new classes of drugs combining potent antihypertensive and antidiabetic actions