Measurement of J/ψ→γηcJ/\psi\to\gamma\eta_{\rm c} decay rate and ηc\eta_{\rm c} parameters at KEDR

Using the inclusive photon spectrum based on a data sample collected at the $J/\psi$ peak with the KEDR detector at the VEPP-4M $e^+e^-$ collider, we measured the rate of the radiative decay $J/\psi\to\gamma\eta_{\rm c}$ as well as $\eta_{\rm c}$ mass and width. Taking into account an asymmetric photon lineshape we obtained $\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33}$ keV, $M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6}$ MeV/$c^2$, $\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6}$ MeV.Comment: 6 pages, 3 figure

Measurement of B(J/psi->eta_c gamma) at KEDR

We present a study of the inclusive photon spectrum from 6.3 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of the radiative decay J/psi -> eta_c gamma, eta_c width and mass. Taking into account an asymmetric photon line shape we obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4 +- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th International Workshop on Charm Physics (Charm2010), October 21-24, 2010, IHEP, Beijin

Measurement of J/psi to eta_c gamma at KEDR

We present a study of the inclusive photon spectra from 5.9 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV, G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009, Beijing, Chin

Measurement of Γee(J/ψ)\Gamma_{ee}(J/\psi) with KEDR detector

The product of the electronic width of the $J/\psi$ meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M $e^+e^-$ collider. The obtained values are: $\Gamma_{ee}(J/\psi) = 5.550 \pm 0.056 \pm 0.089 \, \text{keV},$ $\Gamma_{ee}(J/\psi) \cdot \mathcal{B}_\text{hadrons}(J/\psi) = 4.884 \pm 0.048 \pm 0.078 \, \text{keV},$ $\Gamma_{ee}(J/\psi) \cdot \mathcal{B}_{ee}(J/\psi) = 0.3331 \pm 0.0066 \pm 0.0040 \, \text{keV}.$ The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the $J/\psi$ meson: $\Gamma = 92.94 \pm 1.83 \, \text{keV}.$ These results are consistent with the previous experiments.Comment: 19 pages, 13 figure

Status of “ZELENOGRAD” storage ring

In 2000, after a long break, works on creation of a technological storage ring complex (TSC) have been renewed in ZELENOGRAD. TSC was developed at Budker INP of Siberian Branch of Russian Academy of Science. It consists of a linear accelerator on the electron energy up to 80 MeV, a small storage ring on the energy 450 MeV, a main storage ring on the energy 2 GeV and two electron transfer lines (TL-1 and TL-2). The Main Ring (MR) with energy of electrons 2 GeV is the dedicated synchrotron radiation source intended for the decision of problem of submicron technologies and realization of various researches in a range of wavelengths of 0.2…2000 Å. Linac was mounted and put into operation during 2000-2002. The circulating electron current was received in small storage ring in 2005. Currently, the assembling of TL-2 is being completed. The inspection of the main storage ring equipment made before is carried out. Besides, a modification of all control and power supply system MR is done and a modern electronic element base will be introduced. The status and the nearest planes concerning TSC main storage ring are described.У 2000 р. після довгої перерви відновилися роботи по створенню технологічного накопичувального комплексу - ТНК, у м. Зеленограді. ТНК був розроблений в ІЯФ СВ РАН. Він складається з лінійного прискорювача (ЛП) на енергію до 80 МеВ, малого накопичувача (МН) на енергію 450 МеВ, основного великого накопичувача (ВН) на енергію 2,2 ГеВ і двох каналів перепуску (ЕОК-1 й ЕОК-2). Накопичувач електронів з енергією електронів Е = 2,2 ГеВ є спеціалізованим джерелом СВ, призначеним для вирішення проблем субмікронних технологій, а також для проведення досліджень у проміжку довжин хвиль 0.2…2000 Å. Лінійний прискорювач був змонтований і запущений протягом 2000-2002 р. У 2005 р. був отриманий циркулюючий струм електронів у Малому накопичувачі. У цей час закінчується монтаж ЕОК-2. Проводиться ревізія устаткування ВН. Крім того, проводиться модернізація всіх систем керування і живлення і перехід на сучасну елементну базу. Описується статус ТНК і найближчі плани по монтажу і запуску ВН.В 2000 г. после долгого перерыва возобновились работы по созданию технологического накопительного комплекса – ТНК, в г. Зеленограде. ТНК был разработан в ИЯФ СО РАН. Он состоит из линейного ускорителя (ЛУ) на энергию до 80 МэВ, Малого накопителя (МН) на энергию 450 МэВ, основного большого накопителя (БН) на энергию 2.2 ГэВ и двух каналов перепуска (ЭОК-1 и ЭОК-2). Накопитель электронов с энергией электронов Е = 2.2 ГэВ является специализированным источником СИ, предназначенным для решения проблем субмикронных технологий, а также для проведения исследований в области длин волн 0.2…2000 ангстрем. Линейный ускоритель был смонтирован и запущен в течение 2000-2002 г. В 2005 г. был получен циркулирующий ток электронов в Малом накопителе. В настоящее время заканчивается монтаж ЭОК-2. Проводится ревизия оборудования БН. Кроме того, проводится модернизация всех систем управления и питания и переход на современную элементную базу. Описывается статус ТНК и ближайшие планы по монтажу и запуску БН

Close-out report: schematics and documentation

This report summarizes work on a project to develop a peak detector circuit, making use of the SPICE program. The main idea of the circuit, which was proposed by Comlinear Corporation, is that the voltage on the storing capacitor precisely repeats the input voltage. This is done by using negative feedback. This circuit is part of a proposed beam position monitoring system

A Two Bunch Beam Position Monitor

A new beam position monitor digitizer module has been designed, tested and tuned at SLAC. This module, the electron-positron beam position monitor (epBPM), measures position of single electron and positron bunches for the SLC, LINAC, PEPII injections lines and final focus. The epBPM has been designed to improve resolution of beam position measurements with respect to existing module and to speed feedback correction. The required dynamic range is from 5 x 10{sup 8} to 10{sup 11} particles per bunch (46dB). The epBPM input signal range is from {+-}2.5 mV to {+-}500 mV. The pulse-to-pulse resolution is less than 2 {mu}m for 5 x 10{sup 10} particles per bunch for the 12 cm long striplines, covering 30{sup o} at 9 mm radius. The epBPM module has been made in CAMAC standard, single width slot, with SLAC type timing connector. 45 modules have been fabricated. The epBPM module has four input channels X{sup +}, X{sup -}, Y{sup +}, Y{sup -} (Fig. 1), named to correspond with coordinates of four striplines - two in horizontal and two in vertical planes, processing signals to the epBPM inputs. The epBPM inputs are split for eight signal processing channels to catch two bunches, first - the positron, then the electron bunch in one cycle of measurements. The epBPM has internal and external trigger modes of operations. The internal mode has two options - with or without external timing, catching only first bunch in the untimed mode. The epBPM has an on board calibration circuit for measuring gain of the signal processing channels and for timing scan of programmable digital delays to synchronize the trigger and the epBPM input signal's peak. There is a mode for pedestal measurements. The epBPM has 3.6 {mu}s conversion time