1,407 research outputs found
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 Magnetron Source at FNAL
The magnetron-style 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. 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 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 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 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
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
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
Recent Operation of the FNAL Magnetron Ion Source
This paper will detail changes in the operational paradigm of the Fermi
National Accelerator Laboratory (FNAL) magnetron ion source due to
upgrades in the accelerator system. Prior to November of 2012 the ions
for High Energy Physics (HEP) experiments were extracted at ~18 keV vertically
downward into a 90 degree bending magnet and accelerated through a
Cockcroft-Walton accelerating column to 750 keV. Following the upgrade in the
fall of 2012 the ions are now directly extracted from a magnetron at 35
keV and accelerated to 750 keV by a Radio Frequency Quadrupole (RFQ). This
change in extraction energy as well as the orientation of the ion source
required not only a redesign of the ion source, but an updated understanding of
its operation at these new values. Discussed in detail are the changes to the
ion source timing, arc discharge current, hydrogen gas pressure, and cesium
delivery system that were needed to maintain consistent operation at >99%
uptime for HEP, with an increased ion source lifetime of over 9 months.Comment: 8 p
Direct detection of quantum entanglement
Quantum entanglement, after playing a significant role in the development of
the foundations of quantum mechanics, has been recently rediscovered as a new
physical resource with potential commercial applications such as, for example,
quantum cryptography, better frequency standards or quantum-enhanced
positioning and clock synchronization. On the mathematical side the studies of
entanglement have revealed very interesting connections with the theory of
positive maps. The capacity to generate entangled states is one of the basic
requirements for building quantum computers. Hence, efficient experimental
methods for detection, verification and estimation of quantum entanglement are
of great practical importance. Here, we propose an experimentally viable,
\emph{direct} detection of quantum entanglement which is efficient and does not
require any \emph{a priori} knowledge about the quantum state. In a particular
case of two entangled qubits it provides an estimation of the amount of
entanglement. We view this method as a new form of quantum computation, namely,
as a decision problem with quantum data structure.Comment: 4 pages, 1 eps figure, RevTe
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