Application of photovoltaic electric power to the rural education/communication needs of developing countries

The suitability (i.e., cost competitiveness and reliability) of photovoltaic (PV) power systems for rural applications in developing countries is considered. Potential application sectors include health delivery, education and communication where small amounts of electricity are needed to meet critical needs

High power RF input couplers and test stand for the BERLinPro Project

The bERLinPro project [1], under construction at HZB, is a 100 mA, 50 MeV superconducting RF SRF energy recovery linac ERL being built to study the accelerator technology and physics of operating a high current SRF ERL. For this high current operation, coaxial RF power couplers capable of handling 115 kW of power per coupler, dual couplers per cavity , continuous wave cw at 1.3 GHz are required for both the SRF photo injector and booster cavities. In order to sustain this power level a coupler has been designed based on the high power coupler currently in use at the KEK cERL. Two key changes that were made to the coupler were the modification of the coupler tip, termed a golf tee, as well as increased cooling of the inner conductor. This former modification is incorporated so as to achieve the desired coupling, Qext 105, with minimal coupler penetration into the beam pipe. Herein, we discuss the RF design and properties of the high power coaxial coupler for the photo injector as well as booster cavities of bERLinPro, along with the design of the test stand for conditioning a pair of coupler

Commissioning results of the HZB Quadrupole Resonator

Recent cavity results with niobium have demonstrated the necessity of a good understanding of both the BCS and residual resistance. For a complete picture and comparison with theory, it is essential that one can measure the RF properties as a function of field, temperature, frequency and ambient magnetic field. Standard cavity measurements are limited in their ability to change all parameters freely and in a controlled manner. On the other hand, most sample measurement setups operate at fairly high frequency, where the surface resistance is always BCS dominated. The quadrupole resonator, originally developed at CERN, is ideally suited for characterization of samples at typical cavity RF frequencies. We report on a modified version of the QPR with improved RF figures of merit for high field operation. Experimental challenges in the commissioning run and alternate designs for simpler sample changes are shown alongside measurement results of a large grain niobium sampl

bERLinPro Booster Cavity Design, Fabrication and Test Plans

The bERLinPro project, a 100 mA, 50 MeV superconducting RF SRF Energy Recovery Linac ERL is under construction at Helmholtz Zentrum Berlin for the purpose of studying the technical challenges and physics of operating a high current, c.w., 1.3 GHz ERL. This machine will utilize three unique SRF cryomodules for the injector, booster and linac module respectively. The booster cryomodule will contain three 2 cell SRF cavities, based on the original design by Cornell University, and will be equipped with twin 115 kW RF power couplers in order to provide the appropriate acceleration to the high current electron beam. This paper will review the status of the fabrication of the 4 booster cavities that have been built for this project by Jefferson Laboratory and look at the challenges presented by the incorporation of fundamental power couplers capable of delivering 115 kW. The test plan for the cavities and couplers will be given along with a brief overview of the cryomodule desig

RF input power couplers for high current SRF applications

present day accelerator science. The bERLinPro project is presently being built at HZB to address the challenges involved in high current SRF machines with the goal of generating and accelerating a 100 mA electron beam to 50 MeV in continuous wave cw mode at 1.3 GHz. One of the main challenges in this project is that of handling the high input RF power required for the photo injector as well as booster cavities where there is no energy recovery process. A high power co axial input power coupler is being developed to be used for the photo injector and booster cavities at the nominal beam current. The coupler is based on the KEK cERL design and has been modified to minimise the penetration of the coupler tip in the beam pipe without compromising on beam power coupling Qext 105 . Herein we report on the RF design of the high power 115 kW per coupler, dual couplers per cavity bERLinPro BP coupler along with initial results on thermal calculations. We summarise the RF conditioning of the TTF III couplers modified for cw operation performed in the past at BESSY HZB. A similar conditioning is envisaged in the near future for the low current SRF photo injector and the bERLinPro main linac cryomodule

Booster cavity and fundamental power coupler design issues for bERLinPro

HZB has started building the 50 MeV, 100mA demonstrator energy recovery linac ERL facility bERLinPro. The high power injector system needs to deliver this beam at 6.5 MeV by combining the energy gain of a 1.4 cell SRF photo injector and three Cornell style 2 cell booster cavities. One booster cavity will be operated at zero crossing for bunch energy chirping. Thus two booster cavities have to deliver 2MV each requiring a strong coupling with a loaded Q of 105. To house the two envisaged KEK fundamental power couplers FPC with the cavity, the geometry was slightly modified. Further, to increase coupling and reduce transverse kick effects to the beam, a golf tee antenna tip was designed. This paper summarizes the SRF challenges for the booster cavities, the operational conditions and the modification to the KEK couplers, including tracking calculations to estimate the coupler kick effect to higher orde

First Horizontal Test Results of the HZB SRF Photoinjector for bERLinPro

The bERLinPro project, a small superconducting RF SRF c.w. energy recovery linac ERL is being built at Helmholtz Zentrum Berlin in order to develop the technology required for operation of a high current, 100 mA, 50 MeV ERL. The electron source for the accelerator is a 1.4 cell SRF photoinjector fitted with a multi alkali photocathode. As part of the HZB photoinjector development program three different SRF photoinjectors will be fabricated and tested. The photoinjector described herein is the second cavity that has been fabricated, and the first photoinjector designed for use with a multi alkali photocathode. The photoinjector has been built and tested at JLab and subsequently shipped to HZB for testing in the horizontal test cryostat HoBiCaT prior to installation in the photoinjector cryomodule. This cryomodule will be used to measure the photocathode operation in a dedicated experiment called GunLab, the precursor to installation in the bERLinPro hall. This paper will report on the final results of the cavity installed in the helium vessel in the vertical testing dewar at Jefferson Lab as well as the first horizontal test in HoBiCa

RF Measurements of the 1.6 cell Lead Niobium Photoinjector in HoBiCat

The development of a simple and robust SRF photoinjector capable of delivering 1 mA average current in c.w. operation continues to advance with the horizontal RF testing of the 1.6 cell Pb Nb hybrid photoinjector. This injector utilizes a sputtered lead coating on a removable Nb cathode plug as the photoelectron source and has recently been tested in the horizontal test cryostat facility, HoBiCaT, at Helmholtz Zentrum Berlin. In this paper we will report on the status of these RF measurements and compare the performance to previous vertical RF tests performed at Jefferson Laboratory. We will also provide a summary of the cavity tuning range and microphonics measurements now that it has been installed into a helium vessel equipped with a Saclay style tuner

Case report

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Results from Beam Commissioning of an SRF Plug Gun Cavity Photoinjector

Superconducting rf photo electron injectors SRF photoinjectors hold the promise to deliver high brightness, high average current electron beams for future light sources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid SRF photoinjector based on a Pb coated plug and a Nb rf gun cavity for beam energies up to 2.5MeV at Helmholtz Zentrum Berlin HZB . Emittance measurements and transverse phase space characterization with solenoid scan and slitmask methods will be presente