Ion source development for the proposed FNAL 750-keV injector upgrade

Currently there is a Proposed FNAL 750keV Injector Upgrade for the replacement of the 40 year old Fermi National Laboratory (FNAL) Cockcroft-Walton accelerators with a new ion source and 200MHz Radio Frequency Quadruple (RFQ). The slit type magnetron being used now will be replaced with a round aperture magnetron similar to the one used at Brookhaven National Lab (BNL). Operational experience from BNL has shown that this type of source is more reliable with a longer lifetime due to better power efficiency. The current source development effort is to produce a reliable source with >60mA of H- beam current, 15Hz rep-rate, 100s pulse width, and a duty factor of 0.15%. The source will be based on the BNL design along with development done at FNAL for the High Intensity Neutrino Source (HINS).Comment: 8 pp. 2nd International Symposium on Negative Ions, Beams and Sources: NIBS2010, 16-19 Nov 2010. Takayama, Japa

Performance Characterization of a Solenoid-type Gas Valve for the H−H^{-} Magnetron Source at FNAL

The magnetron-style $H^{-}$ ion sources currently in operation at Fermilab use piezoelectric gas valves to function. This kind of gas valve is sensitive to small changes in ambient temperature, which affect the stability and performance of the ion source. This motivates the need to find an alternative way of feeding H2 gas into the source. A solenoid-type gas valve has been characterized in a dedicated off-line test stand to assess the feasibility of its use in the operational ion sources. $H^{-}$ ion beams have been extracted at 35 keV using this valve. In this study, the performance of the solenoid gas valve has been characterized measuring the beam current output of the magnetron source with respect to the voltage and pulse width of the signal applied to the gas valve.Comment: 4 pp. arXiv admin note: text overlap with arXiv:1701.0175

Implementation of Design Changes Towards a More Reliable, Hands-off Magnetron Ion Source

As the main $H^{-}$ ion source for the accelerator complex, magnetron ion sources have been used at Fermilab since the 1970s. At the offline test stand, new R&D is carried out to develop and upgrade the present magnetron-type sources of $H^{-}$ ions of up to 80 mA and 35 keV beam energy in the context of the Proton Improvement Plan. The aim of this plan is to provide high-power proton beams for the experiments at FNAL. In order to reduce the amount of tuning and monitoring of these ion sources, a new electronic system consisting of a current-regulated arc discharge modulator allow the ion source to run at a constant arc current for improved beam output and operation. A solenoid-type gas valve feeds $H_{2}$ gas into the source precisely and independently of ambient temperature. This summary will cover several studies and design changes that have been tested and will eventually be implemented on the operational magnetron sources at Fermilab. Innovative results for this type of ion source include cathode geometries, solenoid gas valves, current controlled arc pulser, cesium boiler redesign, gas mixtures of hydrogen and nitrogen, and duty factor reduction, with the aim to improve source lifetime, stability, and reducing the amount of tuning needed. In this summary, I will highlight the advances made in ion sources at Fermilab and will outline the directions of the continuing R&D effort.Comment: 4 pp. arXiv admin note: substantial text overlap with arXiv:1701.0175

Improvements on the Stability and Operation of a Magnetron H- Ion Source

The magnetron H- ion sources developed in the 1970s currently in operation at Fermilab provide beam to the rest of the accelerator complex. A series of modifications to these sources have been tested in a dedicated offline test stand with the aim of improving different operational issues. The solenoid type gas valve was tested as an alternative to the piezoelectric gas valve in order to avoid its temperature dependence. A new cesium oven was designed and tested in order to avoid glass pieces that were present with the previous oven, improve thermal insulation and fine tune its temperature. A current-regulated arc modulator was developed to run the ion source at a constant arc current, providing very stable beam outputs during operations. In order to reduce beam noise, the addition of small amounts of N2 gas was explored, as well as testing different cathode shapes with increasing plasma volume. This paper summarizes the studies and modifications done in the source over the last three years with the aim of improving its stability, reliability and overall performance.Comment: 8 pages, 19 figure

Overview of Recent Studies and Design Changes for the FNAL Magnetron Ion Source

This paper will cover several studies and design changes that will eventually be implemented to the Fermi National Accelerator Laboratory (FNAL) magnetron ion source. The topics include tungsten cathode insert, solenoid gas valves, current controlled arc pulser, cesium boiler redesign, gas mixtures of hydrogen and nitrogen, and duty factor reduction. The studies were performed on the FNAL test stand, with the aim to improve source lifetime, stability, and reducing the amount of tuning needed.Comment: 8 p

Determination of the Superconductor-Insulator Phase Diagram for One-Dimensional Wires

We establish the superconductor-insulator phase diagram for quasi-one dimensional wires by measuring a large set of MoGe nanowires. This diagram is consistent with the Chakravarty-Schmid-Bulgadaev phase boundary, namely with the critical resistance being equal to R_Q = h/4e^2. We find that transport properties of insulating nanowires exhibit a weak Coulomb blockade behavior.Comment: 5 pages, 4 figure

An Analysis of Electronic Auctions as a Mechanism for Supply Chain Management

The proliferation of electronic commerce venues on the Web has dramatically expanded the reach of businesses. It is now much easier for a firm to deal directly not only with its customers, but with its entire supply chain. During the past several years, business-to-business transactions have become simpler, faster, and more accurate since the advent of electronic data interchange (EDI) and the explosive growth of information technology. The Internet is introducing yet another way for businesses to electronically conduct transactions in ways that are even more farreaching. Although this has led to some disintermediation at the brick-and-mortar level, new cybermediaries are being created to facilitate and validate the new business relationships. Internet auctions are being touted as one solution for at least some aspects of supply chain management. Attention so far has been primarily focused on the application of the technology. Although the technology facilitates the transactions and interactions of participants by increasing connectivity, other issues are also important in applying electronic auctions to supply chain management. The purpose of this paper is to identify and explore interdisciplinary issues potentially affecting the outcome of electronic business-to-business auctions in order to increase the awareness of Information Systems managers and auction participants so that effective implementation strategies can be developed

Eine Erhebung zur Parasitenkontrolle auf biologisch wirtschaftenden Schaf- und Ziegenbetrieben in der Schweiz

To determine the current control measures for strointestinal nematodes (GIN) on Swiss organic small ruminant farms, a phone questionnaire was developed and conducted. The survey also aimed to assess the understanding and implementation of possible alternative GIN control options. In total, 52 meat sheep and 58 dairy goat farm questionnaires were completed, and it was found that in general, farmers were aware of the potential benefit of an adequate grazing management to reduce GIN infection. However, practical realisation was often limiting. On average it was stated that adult meat sheep and dairy goats were drenched 1.5 and 1.3 times per animal and year, respectively, whilst lambs and kids were treated 1.6 and 1.3 times per animal and year, respectively. Sixteen percent of the interviewed organic goat farmers and 10% of the organic meat sheep farmers stated that they have confirmed anthelmintic resistance on their properties