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3 results on '"Zeuner, T."'

1. Picosecond kinetic confirmation of overlapping Ca cluster and MNa absorption bands in UV grade CaF2.

Author

Zeuner, T., Paa, W., Triebel, W., Mühlig, C., and Stafast, H.

Subjects
*PICOSECOND pulses, *CALCIUM fluoride, *FLUORIDES, *IRRADIATION, *FLUORESCENCE
Abstract

The ArF laser induced absorption feature between 450 and 700 nm observed in the bulk of mono crystalline calcium fluoride (CaF2) upon prolonged 193 nm irradiation is shown to have two origins: The first band at 530 nm is revealed by a transient femtosecond (fs) laser transparency spectrum and attributed to Ca clusters (colloid). The second band at 600 nm originates from MNa centers as identified by their laser induced fluorescence excitation spectrum, emission wavelength, and fluorescence lifetime. The analysis of the absorption feature by fs pump-probe techniques benefits from the different lifetimes of the transient transparency (excited states of the Ca clusters) and the fluorescing MNa centers of about 5 ps and 22 ns, respectively. [ABSTRACT FROM AUTHOR]

Published
2011
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2. Studies of aging and HV break down problems during development and operation of MSGC and GEM detectors for the Inner Tracking System of HERA-B

Author

B Inner Tracker Collaboration, Bagaturia, Y., Baruth, O., Dreis, H. B., Eisele, F., Gorbunov, I., Gradl, S., Gradl, W., Hausmann, S., Hildebrandt, M., Hott, T., Keller, S., Krauss, C., Lomonosov, B., Negodaev, M., Richter, C., Robmann, P., Schmidt, B., Straumann, U., Truoel, P., Visbeck, S., Walter, T., Werner, C., Werthenbach, U., Zech, G., Zeuner, T., and Ziegler, M.

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, business.industry, Detector, Diamond, FOS: Physical sciences, engineering.material, High Energy Physics - Experiment, Anode, High Energy Physics - Experiment (hep-ex), Optics, Electric field, Electrode, engineering, Wafer, Irradiation, business, Instrumentation, HERA-B
Abstract

The results of five years of development of the inner tracking system of the HERA-B experiment and first experience from the data taking period of the year 2000 are reported. The system contains 184 chambers, covering a sensitive area of about 20 * 20 cm2 each. The detector is based on microstrip gas counters (MSGCs) with diamond like coated (DLC) glass wafers and gas electron multipliers (GEMs). The main problems in the development phase were gas discharges in intense hadron beams and aging in a high radiation dose environment. The observation of gas discharges which damage the electrode structure of the MSGC led to the addition of the GEM as a first amplification step. Spurious sparking at the GEM cannot be avoided completely. It does not affect the GEM itself but can produce secondary damage of the MSGC if the electric field between the GEM and the MSGC is above a threshold depending on operation conditions. We observed that aging does not only depend on the dose but also on the spot size of the irradiated area. Ar-DME mixtures had to be abandoned whereas a mixture of 70% Ar and 30% CO2 showed no serious aging effects up to about 40 mC/cm deposited charge on the anodes. X-ray measurements indicate that the DLC of the MSGC is deteriorated by the gas amplification process. As a consequence, long term gain variations are expected. The Inner Tracker has successfully participated in the data taking at HERA-B during summer 2000., Comment: 29 pages, 22 figures

Published
2002
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3. Note: Broadband cavity ring-down spectroscopy of an intra-cavity bulk sample.

Author

Zeuner, T., Paa, W., Mühlig, C., and Stafast, H.

Subjects
*BROADBAND communication systems, *SPECTRUM analysis, *SPECTROMETRY, *IRRADIATION, *RADIATION
Abstract

A cavity ring-down (CRD) setup equipped with a pulsed broadband light source (480 nm <= λ<= 650 nm) and a multichannel detection system (temporal gate width Δτ = 20 ns) is used to simultaneously record the optical loss spectrum of an intra-cavity CaF2 sample and its changes upon transverse ArF laser irradiation at 193 nm. The CRD setup with mirrors of high reflectivity (R > 99.93%) allows to register loss changes of 5 × 10-5 with a spectral resolution of 0.3 nm in less than 2 min. [ABSTRACT FROM AUTHOR]

Published
2013
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