Barrel calorimeter of the CMD-3 detector

The structure of the barrel calorimeter of the CMD-3 detector is presented in this work. The procedure of energy calibration of the calorimeter and the method of photon energy restoration are described. The distinctive feature of this barrel calorimeter is its combined structure; it is composed of two coaxial subsystems: a liquid xenon calorimeter and a crystalline CsI calorimeter. The calorimeter spatial resolution of the photon conversion point is about 2 mm, which corresponds to an angular resolution of ～6 mrad. The energy resolution of the calorimeter is about 8% for photons with energy of 200 MeV and 4% for photons with energy of 1 GeV.     

Signal processing in the neutral-trigger system of the CMD-3 detector

A method for calorimeter-signal processing intended for deriving input signals for the neutral trigger is considered. An algorithm for digitizing signals is described in detail, along with a simulation of its operation. A brief account of data obtained in tests of a prototype of the signal-processing module that employs the developed algorithm is given.     

Simulations for CMS hadron endcap calorimeter upgrade at HL-LHC

The upgrade of the present endcap calorimeters is foreseen to prepare the CMS experiment for the High Luminosity LHC. Integrated doses at the location of the front layers of the hadron endcap calorimeter are expected to reach 20 Mrad. Studies of radiation fields are presented in this report. At the same time, the effects of pileup will become more severe, making the identification of jet objects more challenging. We estimated the effects of different transverse segmentations of back hadron calorimeter (BH) for CMS upgrade.     

Observation of KS0 semileptonic decays with the CMD-2 detector

The decay K_S⁰→πeν has been observed by the CMD-2 detector at the e⁺e⁻ collider VEPP-2M at Novosibirsk. Of 6 million produced K_L⁰K_S⁰ pairs, 75±13 events of the K_S⁰→πeν decay were selected. The corresponding branching ratio is B(K_S⁰→πeν)=(7.2±1.4)×10⁻⁴. This result is consistent with the evaluation of B(K_S⁰→πeν) from the K_L⁰ semileptonic rate and K_S⁰ lifetime assuming ΔS=ΔQ .     

Onboard calibration circuit for the DAMPE BGO calorimeter front-end electronics

DAMPE(DArk Matter Particle Explorer) is a scientific satellite which is mainly aimed at indirectly searching for dark matter in space. One critical sub-detector of the DAMPE payload is the BGO(bismuth germanium oxide) calorimeter, which contains 1848 PMT(photomultiplier tube) dynodes and 16 FEE(Front-End Electronics)boards. VA160 and VATA160, two 32-channel low power ASICs(Application Specific Integrated Circuits), are adopted as the key components on the FEEs to perform charge measurement for the PMT signals. In order to monitor the parameter drift which may be caused by temperature variation, aging, or other environmental factors,an onboard calibration circuit is designed for the VA160 and VATA160 ASICs. It is mainly composed of a 12-bit DAC(Digital to Analog Converter), an operational amplifier and an analog switch. Test results showed that a dynamic range of 0–30 p C with a precision of 5 f C(Root Meam Square, RMS) was achieved, which covers the VA160's input range. It can be used to compensate for the temperature drift and test the trigger function of the FEEs. The calibration circuit has been implemented for the front-end electronics of the BGO Calorimeter and verified by all the environmental tests for both Qualification Model and Flight Model of DAMPE. The DAMPE satellite was launched at the end of 2015 and the calibration circuit will operate periodically in space.     

Energy correction for the BGO calorimeter of DAMPE using an electron beam

The DArk Matter Particle Explorer is an orbital indirect dark matter search experiment which measures the spectra of photons,electrons and positrons originating from deep space.The electromagnetic calorimeter(ECAL),made of bismuth germinate(BGO),is one of the key sub-detectors of DAMPE,and is designed for energy measurement with a large dynamic range from 5 GeV to 10 TeV.In this paper,methods for energy correction are discussed,in order to reconstruct the primary energy of the incident electrons.Different methods are chosen for the appropriate energy ranges.The correction results of Geant4 simulation and beam test data(at CERN) are presented.     

BGO探测器温度特性教学实验装置的研制

针对在教学实验中使用BGO探测器对γ能谱进行测量时由于温度变化引起的峰位漂移、分辨率变化等问题，研制了BGOγ探测器温度特性教学实验装置，并应用于核技术实验教学中。     

Single event effect hardness for the front-end ASICs in the DAMPE satellite BGO calorimeter

The Dark Matter Particle Explorer(DAMPE) is a Chinese scientific satellite designed for cosmic ray studies with a primary scientific goal of indirect detection of dark matter particles. As a crucial sub-detector, the BGO calorimeter measures the energy spectrum of cosmic rays in the energy range from 5 Ge V to 10 Te V. In order to implement high-density front-end electronics(FEE) with the ability to measure 1848 signals from 616 photomultiplier tubes on the strictly constrained satellite platform, two kinds of 32-channel front-end ASICs, VA160 and VATA160,are customized. However, a space mission period of more than 3 years makes single event effects(SEEs) become threats to reliability. In order to evaluate SEE sensitivities of these chips and verify the effectiveness of mitigation methods, a series of laser-induced and heavy ion-induced SEE tests were performed. Benefiting from the single event latch-up(SEL) protection circuit for power supply, the triple module redundancy(TMR) technology for the configuration registers and the optimized sequential design for the data acquisition process, 52 VA160 chips and 32VATA160 chips have been applied in the flight model of the BGO calorimeter with radiation hardness assurance.     

An electromagnetic calorimeter for the silicon detector concept

A silicon-tungsten calorimeter for silicon detector (SiD) at the International Linear Collider is under development. Recent progress is summarized.      

Measurement of space resolution of endcap hadronic calorimeter CMS using beam testing of CMS HCAL prototype in 2003

Results of measurement of space resolution of the hadronic endcap calorimeter (HE) CMS based on data obtained at testing HE prototype on a pion beam at CERN in 2003 are presented. Polar angle resolution as a function of polar angle and pion energy are determined. Coefficients for transition from the shower center to particle coordinates are calculated.     

Separation of electrons and pions in the SND detector calorimeter

A method is developed for discriminating between e⁺e^? → e⁺e^? and e⁺e^? → π⁺π^? events in the center-of-mass (cms) energy range of 0.5 to 1.0 GeV by energy deposition in the electromagnetic calorimeter of the SND detector using a machine learning algorithm. Identification efficiencies for e⁺e^? → e⁺e^? and e⁺e^? → π⁺π^? events are 99.6 and 99.8%, respectively.     

Giant dipole resonance in55Mn* studied with the BGO detector

High-energy gamma-rays emitted in the decay of the giant dipole resonance built on excited states of⁵⁵Mn nucleus were measured with a bismuth germanate detector. Resonance parameters were extracted from the fits to the experimental spectra. Two new high-energy calibration points originating from slow-neutron capture in germanium isotopes of bismuth germanate crystal are proposed for large-volume BGO detectors.     

Measurement of the pion form factor in the range 1.04–1.38 GeV with the CMD-2 detector

The cross section for the process e ⁺ e ⁻ → π⁺π⁻ is measured in the c.m. energy range 1.04—1.38 GeV by analyzing 995 000 selected collinear events including 860000 e ⁺ e ⁻ events, 82000 μ⁺μ⁻ events, and 33000 π⁺π⁻ events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2–4.2 and 5–13%, respectively. __________ Translated from Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, Vol. 82, No. 12, 2005, pp. 841–845. Original Russian Text Copyright ? 2005 by Aul’chenko, Akhmetshin, Banzarov, Barkov, Bashtovoĭ, Bondarev, Bondar’, Bragin, Valishev, Gabyshev, Gorbachev, Grebenyuk, Grigor’ev, Dhawan, Epifanov, Zaĭtsev, Zverev, Ignatov, Kazanin, Karpov, Koop, Krokovny, Kuz’min, Logashenko, Lukin, Lysenko, Mil’shteĭn, Mikhaĭlov, Nesterenko, Nikulin, Otboev, Okhapkin, Perevedentsev, Polunin, Popov, Redin, Roberts, Root, Ruban, Ryskulov, Sibidanov, Sidorov, Skrinsky, Smakhtin, Snopkov, Solodov, Thompson, Fedotovich, Khazin, Hughes, Shamov, Shatunov, Shwartz, éĭdel’man, Yudin. Deceased.     

Development and application of chip calorimeter as an X-ray detector

Radiotherapy for cancer patients requires accurate measurement of the absorbed dose of radiation in a treatment planning step. Various types of radiation detectors are currently utilized for dose measurement. Among them, calorimeters are known to be the most precise detector for measuring absorbed dose, but their on-site application is limited by the large size of the equipment. We developed a miniaturized chip calorimeter for application as a radiation detector. The calorimetric radiation detector was built using micro/nano fabrication techniques, and consists of an SU-8 photoresist absorber and high-sensitivity vanadium oxide (VO_x) thermistors. The thermistors had a temperature resolution of 135 μK, and the calorimeter showed a thermal conductance of 11 μW/K. The detector was irradiated with various X-ray dose rates from a linear accelerator, and the absorbed dose to SU-8 was measured. The detector responses showed high linearity with dose rates, demonstrating the feasibility of the radiation detector for practical uses.     

Double-beta decay with the NEMO experiment: Status of the NEMO 3 detector

The NEMO 3 detector, devoted to search for the neutrinoless double-beta decay, will be able to reach the sensitivity to 〈m _ν〉 of the order of 0.1 eV. The expected performance of the detector for signal detection and both internal and external background rejection is presented. A specific study of the neutron-induced background is given. The NEMO Collaboration is now mounting the detector in the Fréjus underground laboratory.     

The upgrade of endcap CMS muon system

The configuration and composition of the CMS muon system are presented. The paper is focused on cathode strip chambers (CSC) used as the endcap muon system detectors. The goals and objectives of the endcap muon system upgrade are formulated. The main results of works accomplished for the ME1/1 CSCs upgrade and the new ME4/2 muon station construction during the LHC Long Shutdown-1 (2013–2014) are presented. The improved performances of the endcap muon system are shown using experimental data obtained after the upgrade (Run2 data).     

Optimization of endcap trap for single-ion manipulation

Potential distribution is an important characteristic for evaluating the performance of an ion trap. Here, we analyze and optimize the potential distribution of an endcap ion trap for single-ion trapping.We obtain an optimal endcap radius of225 μm–250 μm, endcap-shield gap of ～ 250 μm, and inter-endcap distance of 540 μm–590 μm. The simulation method for analysis can also be applied to other ion traps, which is useful for improving the design and assembly of ion traps.     

Upgrade of hadron endcap calorimeters CMS at LHC

We present the survey of the main tasks in upgrading the hadron endcap (HE) calorimeters of the CMS experiment at LHC. The results of the HE upgrade during the LHC Long Shutdown (2013–2014) and plans for upgrade during LHC Extended Year End Technical Stop (December 2016–May 2017) are discussed.     

Improvement of the technique of identification of electrons and positrons with use of electromagnetic calorimeter of the CLAS detector

We study the dependence of the sensitivity of response of the electromagnetic calorimeter of CLAS plant on the momenta of electrons and positrons. We made calculation of this dependence and elaborated a method for its employment in identification of e⁻ and e⁺. We have shown that the new method of selection of e⁻ and e⁺ improves the quality of identification by about 10%. We used the experimental data obtained with the plant CLAS of linear accelerator at Jefferson laboratory (USA).