Use of a general purpose integrating sphere as a low intensity near-UV extended uniform light source

Vacula, Martin; Horváth, P.; Chytka, L.; Daumiller, K.; Engel, R.; Hrabovský, M.; Mandát, Dušan; Michal, Stanislav; Palatka, M.; Pech, M.; Schäfer, C.; Schovánek, Petr

doi:10.1016/j.ijleo.2021.167169

Cited by 6 publications

(5 citation statements)

References 19 publications

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“…In general, the use of ray tracing software such as TracePro7.4.3 and LightTools8.4.0 is suitable for situations where the uniformity of the irradiance transfer of the IS is below 99%. The primary reason for the inability to simulate high uniformity ISs is the lack of knowledge regarding the BRDF model of the IS coating and the substantial statistical noise generated by Monte Carlo random rays in optical simulations [21]. The secondary reason is that the process requires millions of ray tracings, which is time-consuming.…”

Section: Irradiance Transfer Simulation and Parameter Optimizationmentioning

confidence: 99%

“…The National Institute of Metrology of China used dual precision aperture diaphragms to limit the size of the field of view and successfully measured the irradiance uniformity of LED-ISLS [27]. Researchers such as Martin Vacula used a dual aperture tube combined with a detector to evaluate the irradiance uniformity of the extended ultraviolet IS system [28]. This dual aperture diaphragm radiation detection method has been widely used in remote sensing to calibrate ISs.…”

Section: Experiments Equipmentmentioning

confidence: 99%

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Wide Dynamic Range, High Uniformity Spectral Irradiance Source for Calibration of Scientific-Grade, Large-Size Space Detectors

Kong,

Yuan,

et al. 2024

Remote Sensing

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In order to meet the high uniformity calibration requirements for scientific-grade, large-size space detectors used in the CHES Extrasolar Planet Exploration Mission, this paper presents the design of a wide dynamic range, high uniformity spectral irradiance source (WHUIS). Utilizing a cascade integrating sphere design, and optimizing the overlapping area radiant flux adjustment structure and illumination light path, we achieve a wide dynamic range and high uniformity irradiance output. We established an irradiance transmission model based on the new assumption and analyzed the influence of factors such as illumination distance, stray light, and non-uniform radiance on the uniformity of irradiance output. The model is then validated by building experimental equipment. The findings show that in a circular area of 40 mm, the irradiance uniformity of our light source system exceeds 99.9%, and constant color temperature is adjustable within six orders of magnitude, consistent with the uniformity level predicted by the model.

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Section: Irradiance Transfer Simulation and Parameter Optimizationmentioning

confidence: 99%

Section: Experiments Equipmentmentioning

confidence: 99%

Wide Dynamic Range, High Uniformity Spectral Irradiance Source for Calibration of Scientific-Grade, Large-Size Space Detectors

Kong,

Yuan,

et al. 2024

Remote Sensing

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“…The calibration light source consists of a modified portable general-purpose integrating sphere 3P-GPS-053-SL with a diameter of 13.5 cm [5] and of a temperature-stabilized LED head holding a light source. The issue of integrating spheres as EULSs is summarized in [6]. The light source is a near-UV LED with a peak wavelength of 365 nm covered with an opal glass diffuser to approach the Lambertian emission profile.…”

Section: Xy-scanner Calibration Light Sourcementioning

confidence: 99%

The XY-Scanner for Absolute End-to-End Calibration of Fluorescence Detectors

Vacula

2023

EPJ Web Conf.

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The precise determination of the energy scale is a key part of experiments in astroparticle physics. At the Pierre Auger Observatory, the energy scale is set by the calorimetric measurement of extensive air showers with fluorescence detectors. Thus, the absolute end-to-end calibration of the fluorescence detectors is of utmost importance. In the past, this calibration was performed by illuminating the whole optical system of a fluorescence telescope with a large-scale extended uniform light source of the same diameter as the telescope aperture. However, handling difficulties, excessive manpower requirements, and degradation of such a source led to the need for a different approach for the absolute end-to-end calibration. The fundamental idea of the novel approach is to significantly reduce the geometrical size of the calibration light source, which is a near-UV LED source implemented in a portable integrating sphere with specifically designed interior. This light source is moved over the aperture by a rail mechanism with two independent linear stages named the XY-Scanner. Calibration data are evaluated from a series of light source positions instead of illuminating the entire aperture at once. The absolute photometric determination of the light source emission intensity is performed in a dedicated laboratory setup with a measurement uncertainty of 3.5 %. The XY-Scanner mechanics installed at the aperture gives also the opportunity to install other, devices for instance a narrow, collimated beam source to investigate local impurities of the telescopes. This contribution gives an overview of this novel XY-Scanner calibration method and presents preliminary results and discusses plans for the future.

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“…As light source for the XY-Scanner we employ a ∼13.5 cm (5.3") diameter general purpose integrating sphere of the type 3P-GPS-053-SL manufactured by labsphere [6]. The use of a general purpose integrating sphere as an extended uniform light source is summarized in [7]. This integrating sphere has one large exit port of ∼6.35 cm (2.5") diameter which is reduced to ∼5.04 cm (2") by a port reducer.…”

Section: The Calibration Light-sourcementioning

confidence: 99%

The XY Scanner - A Versatile Method of the Absolute End-to-End Calibration of Fluorescence Detectors

Schäfer¹,

Abreu²,

Aglietta³

et al. 2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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One of the crucial detector systems of the Pierre Auger Observatory is the fluorescence detector composed of 27 large-aperture wide-angle Schmidt telescopes. In the past, these telescopes were absolutely calibrated by illuminating the whole aperture with a uniform large-diameter light source. This absolute calibration was performed roughly once every three years, while a relative calibration was performed on a nightly basis. In this contribution, a new technique for an absolute end-to-end calibration of the fluorescence telescopes is presented. For this technique, a portable, calibrated light source mounted on a rail system is moved across the aperture of each telescope instead of illuminating the whole aperture at once. A dedicated setup using a combination of NIST traceable photodiodes to measure the mean intensity and a PMT for pulse-to-pulse stability tracking has been built for the absolute calibration of the light source. As a result of these complementary measurements, the pulse-to-pulse light source intensity can be known to the 3.5% uncertainty level. The analysis of the readout of the PMT camera at each position of the light source together with the knowledge of the light source emission provides an absolute end-to-end calibration of the telescope. We will give a brief overview of this novel calibration method and its current status as well as show preliminary results from the measurement campaigns performed so far.

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Use of a general purpose integrating sphere as a low intensity near-UV extended uniform light source

Cited by 6 publications

References 19 publications

Wide Dynamic Range, High Uniformity Spectral Irradiance Source for Calibration of Scientific-Grade, Large-Size Space Detectors

Wide Dynamic Range, High Uniformity Spectral Irradiance Source for Calibration of Scientific-Grade, Large-Size Space Detectors

The XY-Scanner for Absolute End-to-End Calibration of Fluorescence Detectors

The XY Scanner - A Versatile Method of the Absolute End-to-End Calibration of Fluorescence Detectors

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