Optimization of ultra-cold neutron scintillation detectors

Novopoltsev, M. I.; Pokotilovskii, Yu. N.

doi:10.1016/0029-554x(80)90463-2

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…The effect is essential when the path length of neutron in a medium is comparable or less than its wavelength. The effect was observed in [183] for isotope 157 Gd for which the real part of the neutron scattering length is much less than the imaginary one. Neutron reflection in this case is due to the latter.…”

Section: Other Experiments With Ucnmentioning

confidence: 94%

“…It was decided to use not differential but integral method: thin layers of copper were deposited by thermal evaporation at the surface of float-glass plates, after irradiation and preparation of the sample the activity was measured as a function of total thickness of deposited copper. These experiments could be finished only much later after reconstruction of IRT-M reactor to IR-8 and construction of new UCN guide with H 2 O ice converter with the UCN flux density about 3 cm −2 s −1 [11]. It was shown that there is no abnormal propagation of the UCN wave function at least at the level 10 −5 .…”

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confidence: 99%

“…The non-reflecting UCN scintillation detectors properly optimized [15] were used mostly in our UCN time-of-flight experiments.…”

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confidence: 99%

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Experiments with ultracold neutrons - first 50 years

Pokotilovski¹

2018

Preprint

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Section: Other Experiments With Ucnmentioning

confidence: 94%

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confidence: 99%

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Experiments with ultracold neutrons - first 50 years

Pokotilovski¹

2018

Preprint

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“…This also leads to distortions in the spectrum. At the end of flight path 17, there is an all-wave UCN detector, described in [18], with a rotating disk 420 mm in diameter with a corrugated paraterphenyl scintillator and a 6 LiF radiator 700 µg/cm 2 thick evaporated onto it. Such a detector does not reflect neutrons [18].…”

Section: Design Of the Ucn Correlation Spectrometermentioning

confidence: 99%

Correlation time-of-flight spectrometry of ultracold neutrons

Novopoltsev

Pokotilovski

2010

Instrum Exp Tech

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The features of the correlation method used in time-of-flight spectrometry of ultracold neutrons are analyzed. The time-of-flight spectrometer for the energy range of ultracold neutrons is described, and results of its testing by measuring spectra of neutrons passing through interference filters are presented. However, at available low intensities, the statistical accuracy of measurements is improved using special methods, e.g., the correlation method discussed in this paper. CORRELATION METHOD IN TIME-OF-FLIGHT SPECTROMETRYThe significant drawback of the standard time-of-flight (TOF) method is its low luminosity, which is defined by the ratio of the duration of the neutron pulse produced by the chopper to the modulation period of the particle beam. Numerous available neutron TOF spectrometers have a duty cycle of a few percent or under. In 1964, the authors of [8,9] independently proposed using the correlation method, which was formerly employed in various fields of experimental physics, in TOF spectrometry. An impetus for further development of the correlation method was received in designing neutron and molecular beam spectrometers (see reviews in [10][11][12] At the initial stages of investigations with UCNs, the neutron fluxes were extremely low, and, sometimes, the neutron background under the experimental conditions was high. This required that the correlation method be used in UCN TOF spectrometry, since it offers a chance to overcome these difficulties. Let us briefly consider the basic principles of the correlation TOF spectrometry.This method implies that a chopper opens n times during beam modulation period T rather than once, as is the case of the classical TOF method. As a result, the effective particle flux incident on the detector increases n times, whereas the background level remains constant. The chopper modulates the particle beam according to the lawwhere g(t) describes beam modulation by a single-slit chopper, and N is the number of elementary intervals with duration ∆T in the period of sequence T = N ∆T . For the standard chopper,and, for the correlation method, a i is the binary sequence of zeros and ones. If channel width of the time analyzer δτ is equal to elementary interval ∆T , the number of neutrons detected in the k-th channel iswhere f i is the TOF spectrum corresponding to the i-th channel of the analyzer, and u k is the mean background level in the channel. In the matrix form, this equation is

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