Hydrogen Maser Work at the National Physical Laboratory

Essen, L.; Donaldson, Ralph W.; Hope, Eric G.; Bangham, M.

doi:10.1088/0026-1394/9/3/004

“…It was pointed out [104] that the wall-shift and the frequency have to be determined in the experiments for the same masers. This generation of experiments [106,104,105,107,108,109,110,111,112] is discussed in the next section. When we speak about two generations we refer to an ideology, rather than to a time-frame.…”

Section: Historical Remarksmentioning

confidence: 99%

Some possibilities for laboratory searches for variations of fundamental constants

Karshenboim¹

2000

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We consider different options for the search for possible variations of the fundamental constants. We give a brief overview of the results obtained with several methods. We discuss their advantages and disadvantages with respect to simultaneous variations of all constants in both time and space in the range 10 8 − 10 10 yr. We also suggest a few possibilities for the laboratory search. Particularly, we propose some experiments with the hyperfine structure of hydrogen, deuterium and ytterbium-171 and of some atoms with a small magnetic moment. Other suggestions are for some measurements of the fine structure associated with the ground state. Special attention is paid to the interpretation of the hfs measurements in terms of variations of the fundamental constants.

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“…2.19 is a complex, ordinary differential equation, that can be solved using the ansatz u = e −iωt , which reduces the differential equation to a quadratic, 20) which has roots at…”

Section: Single Particle Confinementmentioning

confidence: 99%

“…The value in parenthesis gives the total number of events for 50 ms after the magnet shutdown. 30 (36) 20 (20) Left bias 101…”

Section: Initial Search For Trapped Antihydrogen (2009)mentioning

confidence: 99%

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Detection of Trapped Antihydrogen

Hydomako

¹

2013

Springer Theses

0

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The ALPHA experiment is an international effort to produce, trap, and perform precision spectroscopic measurements on antihydrogen (the bound state of a positron and an antiproton). Based at the Antiproton Decelerator (AD) facility at CERN, the ALPHA experiment has recently magnetically confined antihydrogen atoms for the first time. A crucial element in the observation of trapped antihydrogen is ALPHA's silicon vertexing detector. This detector contains sixty silicon modules arranged in three concentric layers, and is able to determine the three-dimensional location of the annihilation of an antihydrogen atom by reconstructing the trajectories of the produced annihilation products.This dissertation focuses mainly on the methods used to reconstruct the annihilation location. Specifically, the software algorithms used to identify and extrapolate charged particle tracks are presented along with the routines used to estimate the annihilation location from the convergence of the identified tracks. It is shown that these methods can determine the annihilation location with a spatial resolution between about 0.6 to 0.8 cm (depending on the coordinate being measured). Furthermore, a robust analysis to identify and reduce cosmic ray background events is described. The cosmic ray background can obscure the trapped antihydrogen signal, and its suppression leads to a significant increase in the annihilation detection sensitivity. The background suppression analysis involves examining the reconstructed detector event based on several selection criteria, including: the number of charged particle tracks, the radial vertex position, and a fit of a straight line to the event hit positions. By carefully optimizing these criteria, (99.54 ± 0.02)% of cosmic ray events are rejected, while (64.4 ± 0.1)% of antihydrogen annihilation events are retained. Finally, the experimental results demonstrating the first-ever magnetic confinement of antihydrogen atoms are presented. These results rely heavily on the silicon i detector, and as such, the role of the annihilation vertex reconstruction is emphasized.

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“…(40). One of them (# 5) [107] was later corrected by the authors [109]. The other (result # 13) was obtained using very different methods.…”

Section: Thirty Years Agomentioning

confidence: 99%

Some possibilities for laboratory searches for variations of fundamental constants

Karshenboim¹

2000

View full text Add to dashboard Cite

We consider different options for the search for possible variations of the fundamental constants. We give a brief overview of the results obtained with several methods. We discuss their advantages and disadvantages with respect to simultaneous variations of all constants in both time and space in the range 10 8 − 10 10 yr. We also suggest a few possibilities for the laboratory search. Particularly, we propose some experiments with the hyperfine structure of hydrogen, deuterium and ytterbium-171 and of some atoms with a small magnetic moment. Other suggestions are for some measurements of the fine structure associated with the ground state. Special attention is paid to the interpretation of the hfs measurements in terms of variations of the fundamental constants.

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Hydrogen Maser Work at the National Physical Laboratory

Cited by 41 publications

References 19 publications

Some possibilities for laboratory searches for variations of fundamental constants

Some possibilities for laboratory searches for variations of fundamental constants

Detection of Trapped Antihydrogen

Some possibilities for laboratory searches for variations of fundamental constants

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