FLUORESCENCE DECAY TIME MEASUREMENTS OF ORGANIC SCINTILLATORS

1962 ◽  
Vol 40 (8) ◽  
pp. 978-991 ◽  
Author(s):  
W. R. Falk ◽  
L. Katz
Keyword(s):  
Alpha Particle ◽  
Decay Time ◽  
Gamma Ray ◽  
Scintillation Counter ◽  
Fluorescence Emission ◽  
Fluorescence Decay ◽  
Total Charge ◽  
Decay Times ◽  
Organic Scintillators ◽  
Main Component

The time dependence of the fluorescence emission from scintillators has been measured for a number of commonly used organic scintillators under alphaparticle and gamma-ray excitation. A sampling oscilloscope was used to record the pulses obtained from a fast scintillation counter. Using such a system, a gating arrangement can be employed which permits selection of only those scintillation events which deliver a predetermined total charge output from the photomultiplier. Noise within the sampling unit limits the measurements to the main fast components in the fluorescence emission. All of the plastic scintillators exhibit decay times between 2.1 and 4.4 nsec. Stilbene exhibits "particle type" discriminating characteristics with a strong second component in the decay (~35 nsec) appearing under alpha-particle excitation. In addition to the main component in the decay of anthracene, evidence of two shorter components was also found. For all the scintillators tested, the alpha-particle induced scintillation had a slightly longer decay time than the corresponding gamma-ray induced scintillation.

Influence of Aggregation on the Fluorescence Decay of Organic Laser Dyes

1978 ◽  
Vol 33 (1) ◽  
pp. 98-104 ◽  
Author(s):  
J. Knof ◽  
F.-J. Theiss ◽  
J. Weber
Keyword(s):  
Decay Time ◽  
Fluorescence Decay ◽  
Laser Dyes ◽  
Temperature Range ◽  
Arrhenius Relationship ◽  
Decay Times ◽  
Organic Laser ◽  
Aggregated Molecules

Singlet decay times in dependence on temperature, concentration, solvent and detergent were measured in solutions of organic laser dyes. In the temperature range from 300 K to 115 K the reciprocal decay time obeys an Arrhenius relationship, the parameters of which were determined. Additional measurements were carried out on Acridinorange because a biexponential fluorescence decay due to monomers (τ = 4.2 ns) and aggregated molecules (τ = 14.7 ns) was found.

SCINTILLATION MECHANISM OF Ce3+ DOPED Gd2SiO5

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3877-3880 ◽  
Author(s):  
K. MORI ◽  
M. YOKOYA ◽  
H. NISHIMURA ◽  
M. NAKAYAMA ◽  
H. ISHIBASHI
Keyword(s):  
Diffusion Coefficient ◽  
Excitation Energy ◽  
Decay Time ◽  
Gamma Ray ◽  
Diffusion Time ◽  
The Core ◽  
Decay Times ◽  
Gamma Ray Irradiation

Measuring the spectra of absorption, luminescence and excitation, and the decay times of the luminescence, at various temperatures, we investigate the scintillation mechanism of Ce 3+ doped Gd 2 SiO 5 (GSO:Ce). We conclude that the excitation energy created by gamma-ray irradiation relaxes to the core exciton states formed by the 4f-4f transitions of Gd 3+, and the core exciton migrates to collide with Ce 3+, and transfers the energy to Ce 3+ to emit the luminescence. We also conclude that the decay time of the Ce 3+ luminescence in GSO:Ce (70 ns for the case of 0.5 mol% of Ce concentration) is decided by the diffusion time of the core exciton. A very small value for the diffusion coefficient of the core exciton is estimated to be 7× 10-7 cm2/s.

A NEW GAMMA TRANSITION FOLLOWING THE DECAY OF 2.4-MINUTE 108AG

1964 ◽  
Vol 42 (11) ◽  
pp. 2173-2179 ◽  
Author(s):  
H. W. Taylor ◽  
T. A. Eastwood
Keyword(s):  
Decay Time ◽  
Gamma Ray ◽  
Gamma Transition ◽  
Full Energy Peak ◽  
Full Energy ◽  
Low Intensity ◽  
Energy Peak ◽  
Gamma Coincidence

A low-intensity peak has been found at 1010 ± 30 keV in the gamma-ray spectrum of 2.4-minute 108Ag obtained with NaI scintillation spectrometers. Consideration of the source-to-crystal distance as well as the effects of absorbers and decay time shows that it is the full-energy peak of a 1010 ± 30 keV gamma ray emitted by 108Ag. Gamma–gamma coincidence studies indicate that this gamma transition occurs between a new level at 1433 ± 30 and the 433-keV level of 108Pd.

Anorganic fluorescence reference materials for decay time of fluorescence emission

2008 ◽  
Author(s):  
A. Engel ◽  
C. Ottermann ◽  
J. Klahn ◽  
T. Korb ◽  
U. Resch-Genger ◽  
...  
Keyword(s):  
Reference Materials ◽  
Decay Time ◽  
Fluorescence Emission

Synthesis and Photophysical Properties of a Conformationally Flexible Mixed Porphyrin Star-Pentamer

2009 ◽  
Vol 62 (7) ◽  
pp. 692 ◽  
Author(s):  
Toby D. M. Bell ◽  
Sheshanath V. Bhosale ◽  
Kenneth P. Ghiggino ◽  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Energy Transfer ◽  
Photophysical Properties ◽  
Fluorescence Decay ◽  
High Yield ◽  
Free Base ◽  
Time Resolved ◽  
Zinc Porphyrin ◽  
Relative Contribution ◽  
Synthetic Strategy ◽  
Decay Times

The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.

A scintillation counter for use in a telescope for gamma-ray astronomy

1974 ◽  
Vol 115 (2) ◽  
pp. 531-537 ◽  
Author(s):  
R.D. Andresen ◽  
I. Arens ◽  
B.G. Taylor ◽  
R.D. Wills
Keyword(s):  
Gamma Ray ◽  
Scintillation Counter ◽  
Gamma Ray Astronomy

Mn4+ non-equivalent doped fluoride phosphor towards a short fluorescence decay time for backlighting

2022 ◽  
Author(s):  
Jie Li ◽  
Xinyi Yang ◽  
Tong Li ◽  
Yan-Qing Ye ◽  
Yayun Zhou ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Fluorescence Lifetime ◽  
Decay Time ◽  
Fluorescence Decay ◽  
Compensation Mechanism ◽  
Exchange Method ◽  
Fluorescence Decay Time ◽  
Ion Exchange Method

The non-equivalent doping of Mn4+ in the red-emitting fluoride phosphors effectively shortens the fluorescence lifetime. Herein, we successfully synthesized Rb2NaInF6:Mn4+ phosphors by an ion-exchange method. The compensation mechanism of Mn4+...

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