Test and characterization of a prototype silicon-tungsten electromagnetic calorimeter

New generation high-energy physics experiments demand high precision tracking and accurate measurements of a large number of particles produced in the collisions of lementary particles and heavy-ions. Silicon-tungsten (Si-W) calorimeters provide the most viable technological option to meet the requirements of particle detection in high multiplicity environments. We report a novel Si-W calorimeter design, which is optimized for $\gamma/\pi^0$ discrimination up to high momenta. In order to test the feasibility of the calorimeter, a prototype mini-tower was constructed using silicon pad detector arrays and tungsten layers. The performance of the mini-tower was tested using pion and electron beams at the CERN Proton Synchrotron (PS). The experimental results are compared with the results from a detailed GEANT-4 simulation. A linear relationship between the observed energy deposition and simulated response of the mini-tower has been obtained, in line with our expectations.Comment: 13 figures, represents test beam data with PS beam line at CER

Impact of Peppermint Therapy on Dysphagia and Non-cardiac Chest Pain: A Pilot Study.

BACKGROUND: Due to its smooth muscle relaxing properties, peppermint oil (PO) may relieve dysphagia and chest pain due to esophageal motility disorders. AIM: To explore the impact of PO on dysphagia and/or chest pain in patients referred for motility testing. METHODS: Patients initiated on PO for dysphagia and/or chest pain from 2013 to 2016 were identified. We excluded patients with obstructing esophageal lesions, patients lost to follow-up, and those with preexisting cardiac conditions. Concentrated PO was given as commercially available dissolvable peppermint tablets; two tablets before meals were prescribed to patients with dysphagia and on an as-needed basis for patients with chest pain. Patient-reported symptom response was assessed using a modified five-point Likert scale. RESULTS: Thirty-eight patients were included. Twenty-four patients (63%) reported improvement; 12 were much better and 12 were slightly better. Fourteen experienced no change and none reported feeling worse. Based on pre-treatment HRM, patients with distal esophageal spasm (DES) (n = 10) and esophagogastric junction outflow obstruction (EGJOO) (n = 8) appeared to demonstrate the best subjective improvement (83% and 100%, respectively) (P \u3c 0.05). CONCLUSION: PO appears to provide symptomatic relief in some patients with dysphagia and CP. Presence of a well-defined manometric disorder, particularly DES or EGJOO, appeared to predict response

Development of indigenous silicon detector and readout electronics for forward electromagnetic calorimeter prototypes

ALICE is a high-energy physics experiment at the CERN Large Hadron Collider (LHC) in Geneva, to study the properties of quark-gluon plasma, formed in heavy-ion collisions. In the upgrade program, a new electromagnetic forward calorimeter (FOCAL) based on silicon and tungsten (Si$+$W) sampling configuration, has been proposed to address new physics objectives of ALICE experiment. The high luminosity environment of the LHC and the requirement of compact design for the FOCAL, put stringent requirements for the development of silicon detector and front-end electronics (FEE). The ALICE-India collaboration made the first proposal for the FOCAL in the year 2008, and initiated indigenous R &D; activities for silicon detectors, FEE and instrumentation. As a result, large area (40 cm$^2$), segmented silicon pad sensors (6.3 cm $\times$ 6.3 cm with 36 pads) and two different FEE application-specific integrated circuits (ASICs), ANUSANSKAR and ANUINDRA respectively, were developed. Progressive FOCAL prototypes were built using these sensors and ASICs, which have undergone test beam validation in a phased manner achieving the desired calorimetric performances, in line with the GEANT-based performance simulations. Further, the results of the test beam experiments provided crucial inputs for achieving the technical specifications of the silicon detector and readout electronics for the final calorimeter. This manuscript presents, in a chronological order, India’s indigenous FEE ASICs, sensor and instrumentation development and reports the subsequently improved readout methodology for the prototype FOCAL detector

Fabrication and beam test of a silicon-tungsten electromagnetic calorimeter

A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1 cm2) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from −300 fC to +500 fC. Another ASIC with a larger dynamic range, ± 600 fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characterise the response to minimum ionising particles (MIP) and showers from electromagnetic (EM) interactions. Pion beams of 120 GeV provided baseline measurements towards the understanding of the MIP behaviour in the silicon pad layers, while electron beams of energy from 5 GeV to 60 GeV rendered detailed shower profiles within the calorimeter. The energy deposition in each layer, the longitudinal shower profile, and the total energy deposition have been measured for each incident electron energy. Linear behaviour of the total measured energy (E) with that of the incident particle energy (E0) ensured satisfactory calorimetric performance. For a subset of the data sample, selected based on the cluster position of the electromagnetic shower of the incident electron, the dependence of the measured energy resolution on E0 has been found to be σ/E = (15.36/&surd;E0(GeV) ⊕ 2.0) %.A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1~cm$^2$) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from $-300$~fC to $+500$~fC. Another ASIC with a larger dynamic range, $\pm 600$~fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characterise the response to minimum ionising particles (MIP) and showers from electromagnetic (EM) interactions. Pion beams of 120 GeV provided baseline measurements towards the understanding of the MIP behaviour in the silicon pad layers, while electron beams of energy from 5 GeV to 60 GeV rendered detailed shower profiles within the calorimeter. The energy deposition in each layer, the longitudinal shower profile, and the total energy deposition have been measured for each incident electron energy. Linear behaviour of the total measured energy ($E$) with that of the incident particle energy ($E_{0}$) ensured satisfactory calorimetric performance. For a subset of the data sample, selected based on the cluster position of the electromagnetic shower of the incident electron, the dependence of the measured energy resolution on $E_{0}$ has been found to be $\sigma/E = (15.36/\sqrt{E_0(\mathrm{GeV)}} \oplus 2.0) \%$

The Homeobox Transcription Factor RHOX10 Drives Mouse Spermatogonial Stem Cell Establishment

The developmental origins of most adult stem cells are poorly understood. Here, we report the identification of a transcription factor-RHOX10-critical for the initial establishment of spermatogonial stem cells (SSCs). Conditional loss of the entire 33-gene X-linked homeobox gene cluster that includes Rhox10 causes progressive spermatogenic decline, a phenotype indistinguishable from that caused by loss of only Rhox10. We demonstrate that this phenotype results from dramatically reduced SSC generation. By using a battery of approaches, including single-cell-RNA sequencing (scRNA-seq) analysis, we show that Rhox10 drives SSC generation by promoting pro-spermatogonia differentiation. Rhox10 also regulates batteries of migration genes and promotes the migration of pro-spermatogonia into the SSC niche. The identification of an X-linked homeobox gene that drives the initial generation of SSCs has implications for the evolution of X-linked gene clusters and sheds light on regulatory mechanisms influencing adult stem cell generation in general

Fabrication and beam test of a silicon-tungsten electromagnetic calorimeter

A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1 cm2) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from -300 fC to +500 fC. Another ASIC with a larger dynamic range, ± 600 fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characterise the response to minimum ionising particles (MIP) and showers from electromagnetic (EM) interactions. Pion beams of 120 GeV provided baseline measurements towards the understanding of the MIP behaviour in the silicon pad layers, while electron beams of energy from 5 GeV to 60 GeV rendered detailed shower profiles within the calorimeter. The energy deposition in each layer, the longitudinal shower profile, and the total energy deposition have been measured for each incident electron energy. Linear behaviour of the total measured energy (E) with that of the incident particle energy (E0) ensured satisfactory calorimetric performance. For a subset of the data sample, selected based on the cluster position of the electromagnetic shower of the incident electron, the dependence of the measured energy resolution on E0 has been found to be σ/E = (15.36/√E0(GeV) ⊕ 2.0) %

Fabrication and beam test of a silicon-tungsten electromagnetic calorimeter

A silicon-tungsten (Si-W) sampling calorimeter, consisting of 19 alternate layers of silicon pad detectors (individual pad area of 1 cm2) and tungsten absorbers (each of one radiation length), has been constructed for measurement of electromagnetic showers over a large energy range. The signal from each of the silicon pads is readout using an ASIC with a dynamic range from -300 fC to +500 fC. Another ASIC with a larger dynamic range, ± 600 fC has been used as a test study. The calorimeter was exposed to pion and electron beams at the CERN Super Proton Synchrotron (SPS) to characterise the response to minimum ionising particles (MIP) and showers from electromagnetic (EM) interactions. Pion beams of 120 GeV provided baseline measurements towards the understanding of the MIP behaviour in the silicon pad layers, while electron beams of energy from 5 GeV to 60 GeV rendered detailed shower profiles within the calorimeter. The energy deposition in each layer, the longitudinal shower profile, and the total energy deposition have been measured for each incident electron energy. Linear behaviour of the total measured energy (E) with that of the incident particle energy (E0) ensured satisfactory calorimetric performance. For a subset of the data sample, selected based on the cluster position of the electromagnetic shower of the incident electron, the dependence of the measured energy resolution on E0 has been found to be σ/E = (15.36/√E0(GeV) ⊕ 2.0) %