Ionization cooling is the preferred method for producing bright muon beams. This cooling technique requires the operation of normal conducting, radio-frequency (rf) accelerating cavities within the ...multi-tesla fields of dc solenoid magnets. Under these conditions, cavities exhibit increased susceptibility to rf breakdown, which can damage cooling channel components and imposes limits on channel length and transmission efficiency. We report, for the first time, stable high-vacuum, normal-conducting cavity operation at gradients of50MV/min an external magnetic field of three tesla, through the use of beryllium cavity elements. This eliminates a significant technical risk that has previously been inherent in ionization cooling channel designs.
A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, ...whose mean momenta vary from 171 to 281 MeV/
c
, have emittances of approximately 1.2–2.3
π
mm-rad horizontally and 0.6–1.0
π
mm-rad vertically, a horizontal dispersion of 90–190 mm and momentum spreads of about 25 MeV/
c
. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.
In this paper we develop an a priori method for simulating dynamic resonant frequency and temperature responses in a radio frequency quadrupole (RFQ) and its associated water-based cooling system ...respectively. Our model provides a computationally efficient means to evaluate the transient response of the RFQ over a large range of system parameters. The model was constructed prior to the delivery of the PIP-II Injector Test RFQ and was used to aid in the design of the water-based cooling system, data acquisition system, and resonance control system. Now that the model has been validated with experimental data, it can confidently be used to aid in the design of future RFQ resonance controllers and their associated water-based cooling systems. Without any empirical fitting, it has demonstrated the ability to predict absolute temperature and frequency changes to 11% accuracy on average, and relative changes to 7% accuracy.
Performance of the MICE diagnostic system Bogomilov, M.; Tsenov, R.; Vankova-Kirilova, G. ...
Journal of instrumentation,
08/2021, Letnik:
16, Številka:
8
Journal Article
The ADMX collaboration gathered data for its Run 1A axion dark matter search from January to June 2017, scanning with an axion haloscope over the frequency range 645-680 MHz (2.66-2.81 μeV in axion ...mass) at DFSZ sensitivity. The resulting axion search found no axion-like signals comprising all the dark matter in the form of a virialized galactic halo over the entire frequency range, implying lower bound exclusion limits at or below DFSZ coupling at the 90% confidence level. This paper presents expanded details of the axion search analysis of Run 1A, including review of relevant experimental systems, data-taking operations, preparation and interpretation of raw data, axion search methodology, candidate handling, and final axion limits.
The Axion Dark Matter eXperiment (ADMX) has previously excluded Dine-Fischler-Srednicki- Zhitnisky (DFSZ) axions between 680-790 MHz under the assumption that the dark matter is described by the ...isothermal halo model. However, the precise nature of the velocity distribution of dark matter is still unknown, and alternative models have been proposed. Here, we report the results of a non-virialized axion search over the mass range 2.81–3.31 µeV, corresponding to the frequency range 680–800 MHz. This analysis marks the most sensitive search for non-virialized axions sensitive to Doppler effects in the Milky Way Halo to date. Accounting for frequency shifts due to the detector’s motion through the Galaxy, we exclude cold flow relic axions with a velocity dispersion of $\mathscr{O}$(10-7)c with 95% confidence.
The ϕ-meson leptonic widths, Γee and Γμμ, are obtained, respectively, from the e+e− forward–backward asymmetry and the μ+μ− cross section around the ϕ-mass energy. We find Γee=1.32±0.05±0.03 keV and ...ΓeeΓμμ=1.320±0.018±0.017 keV. These results, compatible with Γee=Γμμ, provide a precise test of lepton universality. Combining the two results gives Γℓℓ(ϕ)=1.320±0.023 keV.
This Letter reports results from a haloscope search for dark matter axions with masses between 18 2.66 and 2.81 eV. The search excludes the range of axion-photon couplings predicted by plausible 19 ...models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume 20 haloscope at sub-Kelvin temperatures, thereby reducing thermal noise as well as the excess noise 21 from the ultra-low-noise SQUID amplier used for the signal power readout. Ongoing searches will 22 provide nearly denitive tests of the invisible axion model over a wide range of axion masses.
Generally the basic sciences of physics, chemistry and mathematics and the applied sciences of anatomy physiology and pharmacology are associated with the history of the development and advancement ...of anaesthesia. In considering the history of infection control in anaesthesia, the contribution of microbiology must be added to the above. When sifting through old books and journals it is often difficult to understand the stimuli for the leaps of progress; I believe the zeitgeist is often the invisible (to our eyes) all important factor. An attempt to briefly illustrate some of the main events and characters follows.
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