Enhanced quantum efficiency for CsI grown on a graphite-based substrate coating

Friese, J.; Gernhäuser, R.; Homolka, J.; Kastenmüller, A.; Maier-Komor, P.; Peter, M.; Zeitelhack, K.; Kienle, P.; Körner, H. J.

doi:10.1016/s0168-9002(99)00663-4

Cited by 33 publications

(17 citation statements)

References 13 publications

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“…This angular distribution is chosen due to the roughness of the graphite surface (see Fig 2a in Ref. [67]). Electric fields which guide the electrons towards the CEM are computed setting the CEM input voltage to +270 V and all other surfaces to ground potential.…”

Section: B22 Simulation Of Electric Field Configurationmentioning

confidence: 99%

The Rydberg constant and proton size from atomic hydrogen

Beyer

Maisenbacher

Matveev

et al. 2017

Science

374

427

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ZusammenfassungDas Wasserstoffatom (H) stellt ein einzigartiges System für Tests der Quanten-Elektrodynamik dar. Aufgrund seiner einfachen Struktur und genauen theoretischen Beschreibung liefert es außerdem wichtige Daten für die Bestimmung der RydbergKonstante R ∞ und des Proton-Ladungsradius r p im Rahmen der globalen Anpassung fundamentaler Konstanten durch das Committee on Data for Science and Technology (CODATA). Im Jahre 2010 kam das sogenannte "proton size puzzle" auf, eine Diskrepanz von sieben Standardabweichungen zwischen CODATA und dem zehn mal genauer gemessenen Wert von r p in myonischem Wasserstoff (µ -p, [1, 2] AbstractThe hydrogen atom (H) is a unique system for tests of quantum electrodynamics (QED). Due to its simplicity and accurate theoretical description, it also provides key input data for the determination of the Rydberg constant R ∞ and the proton root mean square (r.m.s.) charge radius r p in the global adjustment of fundamental constants [4] by the Committee on Data for Science and Technology (CODATA). In the year 2010, the "proton size puzzle" emerged, which refers to a discrepancy of seven standard deviations between CODATA and a ten times more accurate measurement of r p in muonic hydrogen (µ -p, [1, 2]). Proposed solutions for this puzzle cover a wide range of scenarios, up to physics beyond the standard model [3]. This thesis reports on a novel scheme for high resolution spectroscopy of dipole allowed 2S -nP transitions in H, using a cryogenic beam of H atoms that are prepared in the meta-stable 2S F =0 1/2 state by state selective optical excitation. Such measurements can be used for a new determination of R ∞ and r p from H spectroscopy, shedding new light on the "proton size puzzle". The scheme has been applied to spectroscopy of the 2S-4P transition first, yielding: These values are as accurate as the ones determined from the aggregate world data of precision H spectroscopy (15 measurements) that enter the CODATA adjustment. While a discrepancy of 3.8 combined standard deviations is found to the latter, the presented results agree with the measurements in µ -p. The 2S-4P experiment is essentially unaffected by the systematic effects dominating the uncertainties in the previous most precise determinations of R ∞ using dipole forbidden two photon transitions in H. Instead, the main systematic effects are the first order Doppler effect, canceled by the use of an active fiber-based retroreflector (AFR) developed in this thesis, and line shape distortions due to quantum interference (QI) of neighboring atomic resonances. The latter effect has come to the attention of the precision spectroscopy community only recently [8,9]. Apparent QI line shifts have been studied experimentally, yielding the first direct observation in precision spectroscopy of largely separated atomic resonances. The observed shifts of up to ± 51 kHz are six times larger than the proton size discrepancy for the 2S-4P transition. They are brought under control by a suitable line shape model function, derived and...

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Section: B22 Simulation Of Electric Field Configurationmentioning

confidence: 99%

The Rydberg constant and proton size from atomic hydrogen

Beyer

Maisenbacher

Matveev

et al. 2017

Science

374

427

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“…Much research and development (influence of substrate, conditioning, thickness, evaporation procedure, transfer to the chamber) was needed to make the technique mature [26]- [29]. The stability of the CsI photocathodes in a chamber was studied over several years with promising results (Fig.…”

Section: Photon Detector Mature: Csimentioning

confidence: 99%

Recent progress in Cerenkov counters

Križan

2001

IEEE Trans. Nucl. Sci.

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“…A slightly modified procedure was followed by the HADES RICH group: the substrate cathode was covered by spraying a film of resin-stabilized graphite prior to the coating of 500 nm CsI [20].…”

Section: Introductionmentioning

confidence: 99%

“…The CsI ageing properties have been thoroughly investigated [19][20][21][22]; no QE degradation due to ion bombardment is observed up to an accumulated charge of 0.2 mC/cm 2 , which allows up to $5-10 years (depending on accelerator running efficiency) of stable response for particle and photon fluxes of $ 10 Hz/cm 2 and operation at moderate gain (below $ 5 Â 10 4 ). After several years of running, all detectors have shown a consistent behavior, with no or negligible QE decrease.…”

Section: Introductionmentioning

confidence: 99%