Detector identification by waveform shape analysis for effective data acquisition; Improvements in time resolution and count rate for positron annihilation age-momentum correlation measurement

Hirade, Tetsuya; Ando, Hirokazu*; Manabe, Kensuke*; Ueda, Daisuke*

Nuclear Instruments and Methods in Physics Research A, 931, p.100 - 104, 2019/07

https://doi.org/10.1016/j.nima.2019.04.047

A detector identification method using waveform-shape analysis is proposed. A method for enabling discrimination of detectors by making a characteristic waveform shape for every detector by each own loop circuit on the detector is shown as an example. This method can be applied in many experimental contexts with detectors, making a high counting rate possible. Moreover, detector identification can be used for other important questions such as detector position. As an example, this detector identification method is used to perform positron-annihilation age-momentum correlation measurement with a high temporal resolution and a high counting rate.

Effect of heavy ion irradiation to the silkworm eggs at before fertilization and at nuclear cleavage stage

Ueda, Daisuke*; Shirai, Koji*; Funayama, Tomoo; Sakashita, Tetsuya; Yokota, Yuichiro; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 84, 2015/03

https://doi.org/10.11484/jaea-review-2014-050

In this study, we investigated the effects of irradiation to the silkworm eggs at various developmental stages. First, we tried the irradiation to the unfertilized eggs (at 1.5 hour after oviposition). At this stage, the female pronucleus and the sperm nucleus are observed in the eggs, but not fertilized. After irradiation, the irradiated eggs stopped the development after fertilization. About 2 hours after, the egg restarted the nuclear cleavage. This result indicates the DNA damage on pronuleus cannot prevent the fertilization. We also investigated the effects of irradiation to the egg at the nuclear cleavage stage (at 6 hour after oviposition). The egg also stopped the development after irradiation, but the duration time of the developmental arrest was almost two times longer (about 4 hours) than that of the egg irradiated at fertilization.

Influences of humid substances, alkaline conditions and colloids on radionuclide migration in natural barrier

Mukai, Masayuki; Ueda, Masato; Inada, Daisuke; Yukawa, Kazuhiko; Maeda, Toshikatsu; Iida, Yoshihisa

Proceedings of International Symposium NUCEF 2005, p.219 - 224, 2005/08

For better quantitative understanding of radionuclide migration for safety assessment of geologic disposal, JAERI has been conducting experimental and modeling studies on influences of humic substances, highly alkaline conditions and colloids on sorptive and diffusional behavior of TRU in geologic materials. In the absence of fulvic acid, one of humic substances, diffusion of Am through a tuff sample was not detected. By adding fulvic acid, Am was detected in the downstream cell, which indicates the diffusion through the sample. Highly alkaline conditions arisen from cementitious materials may spread by altering chemical and physical properties of geologic materials. Through-diffusion experiments of alkaline species in granite showed that the effective diffusion coefficient of Ca and OH in a cement-equilibrated aqueous solution were found to be higher by almost two orders of magnitude than Na and OH in a NaOH solution. Radionuclide migration can be enhanced by colloids, and thus a calculation code describing the effect of colloids on radionuclide migration has been required.

Heavy ion irradiation-induced cell cycle arrest in multinuclear silkworm egg having non-damaged and damaged nuclei

Ueda, Daisuke*; Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Shirai, Koji*

no journal, , 

The occurrence of DNA damage-induced cell cycle arrest is consider to depend on the amount and/or seriousness of DNA damage. However, the detailed mechanisms have been obscure. When whole egg of the silkworm in early embryogenesis was subjected to carbon ions, the developmental arrest was observed, however, about 2 hours after irradiation, the mitotic cleavage resumed, indicating the eggs at this stage can induce the cell cycle arrest by checkpoints after irradiation. On the other hand, the locally targeted irradiation with carbon-ion microbeam to 10% of the nuclei was not able to induce the developmental arrest. In the egg, several of abnormal cleaved nuclei were observed, which are considered to be the irradiated nuclei that stop their cleavage. Meanwhile, when 30-40% of nuclei were irradiated, the embryonic development stopped. The result indicate the checkpoint-induced arrest of the silkworm egg at intralecithal cleavage stage may depend on number or ratio of the damaged nuclei.

New method for high counting rate of positron annihilation age-momentum correlation (AMOC) measurement

Hirade, Tetsuya; Ando, Hirokazu*; Manabe, Kensuke*; Ueda, Daisuke*

no journal, , 

Although positron annihilation ray age-momentum correlation (AMOC) measurements can give information that cannot be obtained by other methods, it takes a long time to measure. The time resolution and the counting rate are in a trade-off relationship. We tried to improve the counting rate by increasing detectors. If the position of the detector deviates by 1 mm, it shifts 3 ps on the time axis. Even if multiple detectors are introduced, it is very difficult to match the time information obtained by each detector. Therefore, we have introduced each characteristic waveform to the signal from every detector. It was possible to identify a detector by use of a characteristic shape of waveforms, i.e. every spectrum for each detectors can be obtained. Afterward, every time shift for each spectrum can be calculated and then finally all of the events can be analyzed by correcting time shifts to construct one spectrum. Hence we succeeded to perform high count rate AMOC measurements.

陽電子消滅寿命測定装置、放射線計測器の調整方法、放射線計測器

平出 哲也; 安藤 太一; 真鍋 賢介; 上田 大介

not registered

JP, 2017-239693  Patent licensing information  Patent publication (In Japanese)

【課題】複数の放射線検出器を並列に用いた場合に、各放射線検出器を同時に用いて高精度の測定を行わせる。 【解決手段】スタート用検出器11Aからのパルス出力P0A、スタート用検出器11Bからのパルス出力P0Bと、ストップ用検出器からのパルス出力P1との間の時間差ΔTを測定し、ΔTのヒストグラムを生成する。パルス出力P1とパルス出力P0Bの時間間隔は、パルス出力P0Aを基準とした場合において、本来の時間間隔であるΔTBに加えて一様にシフト時間Tだけ広がるように設定される。測定されたΔTのヒストグラムである図2の(III)においては、ΔTBに対してTが一様に付加されたために、左側のピークの分布がΔTAのヒストグラムに対応し、右側のピークの分布がΔTBのヒストグラムに対応する。このΔTBのヒストグラムを横軸方向にシフトさせれば、ΔTAのヒストグラムと重複させることができる。