RF system of electron injector for the race-track microtron-recuperator and results of its operation with electron beam

The RF system is a part of the 1.6 - 2 MeV injector for the Race-Track Microtron - Recuperator (RTMR) that is under construction at BINP, Novosibirsk, for the Center of Photochemistry. RF system has three 180.4 MHz cavities. Buncher cavity operates at the accelerating voltage of 100 kV and two accelerating cavities operate at the gap voltage up to 800 kV. Cavities are driven by 3 power amplifiers. Maximum output power of amplifier which feeds the accelerating cavity is 130 kW. Low level electronics controls phase and amplitude of RF cavity gap voltages and generates signals for synchronization of the electron gun. Maximum current of injector (45 mA) is realized at 22.5 MHz repetition rate of electron bunches. The effects of beam – RF cavities interaction and the RF system operation results are presented

Test of the RF system for damping ring

RF system for VEPP-5 damping ring is described. The system consists of RF power supply, waveguide section, and 700 MHz cavity. Results of computer simulations and measurements of HOM spectrum and damping efficiency are presented together with the results of cavity testing at operating power level

FIRST TEST RESULTS OF RF GUN FOR THE RACE-TRACK MICROTRON RECUPERATOR OF BINP SB RAS*

Abstract A new electron source for the Race-Track Microtron Recuperator is being developed by BINP SB RAS. It will increase average beam current and brightness of synchrotron radiation. Instead of the static 300kV electron gun operated now we are developing RF gun with the same energy of electrons. This RF gun consists of RF cavity with a gridded thermo cathode mounted on the back wall. RF cavity is driven by a 60 kW generator with last stage equipped by GU101A tetrode tube. Operational frequency of the cavity is 90.2 MHz. It is equal to the second subharmonic of the Microtron RF system frequency. A set of low power electronics controls amplitude of the cavity voltage and its tuner. This system, including a diagnostics beam line, has been installed to serve as a test bench to test the RF cavity and for beam dynamics studies. In continuous regime the designed 300 kV voltages at the acceleration gap is obtained. This paper summarizes the first test results of the cavity in this configuration

Status of RF system for VEPP-5 damping ring

The paper presents the RF system of VEPP-5 damping ring created at BINP Novosibirsk. The RF system operates at 700 MHz and consists of the generator based on KU-393 klystron, transmitting waveguide with wave-to-coax adapters, accelerating cavity, and control system. HOM cavities are damped with resistive loads to eliminate the beam instability. Parameters and results of cold measurement tests and high power level tests are presented.Представлена ВЧ-система накопителя-охладителя для ВЭПП-5, созданная в БИЯФ, Новосибирск. ВЧ-система работает на частоте 700 МГц и состоит из генератора на клистроне КУ-393,передающего волновода с коаксиально-волноводными переходами, ускоряющего резонатора и системы управления и контроля. Для устранения пучковой неустойчивости высшие моды резонатора подавлены с помощью резистивных нагрузок. Приведены параметры и результаты холодных измерений и горячих испытаний ВЧ-системы.Представлено ВЧ-система нагромаджувача-охолоджувача для ВЕПП-5, що створена в БІЯФ, Новосибірськ. ВЧ-система працює на частоті 700 МГц і складається з генератора на клістроні КУ-393, передаючого хвилеводу з коаксіально-хвилеводними переходами, прискорюючого резонатора і системи керування і контролю. Для усунення пучкової нестійкості вищі моди резонатора подавлені за допомогою резистивних навантажень. Наведено параметри і результати холодних вимірів і гарячих випробувань ВЧ- системи

Gain-of-function genetic screens in human cells identify SLC transporters overcoming environmental nutrient restrictions.

Solute carrier (SLC) transporters control fluxes of nutrients and metabolites across membranes and thereby represent a critical interface between the microenvironment and cellular and subcellular metabolism. Because of substantial functional overlap, the interplay and relative contributions of SLCs in response to environmental stresses remain poorly elucidated. To infer functional relationships between SLCs and metabolites, we developed a strategy to identify SLCs able to sustain cell viability and proliferation under growth-limiting concentrations of essential nutrients. One-by-one depletion of 13 amino acids required for cell proliferation enabled gain-of-function genetic screens using a SLC-focused CRISPR/Cas9-based transcriptional activation approach to uncover transporters relieving cells from growth-limiting metabolic bottlenecks. Among the transporters identified, we characterized the cationic amino acid transporter SLC7A3 as a gene that, when up-regulated, overcame low availability of arginine and lysine by increasing their uptake, whereas SLC7A5 was able to sustain cellular fitness upon deprivation of several neutral amino acids. Moreover, we identified metabolic compensation mediated by the glutamate/aspartate transporters SLC1A2 and SLC1A3 under glutamine-limiting conditions. Overall, this gain-of-function approach using human cells uncovered functional transporter-nutrient relationships and revealed that transport activity up-regulation may be sufficient to overcome environmental metabolic restrictions