Tue·Jan 9, 2018Tuesday·January 9, 2018

1. 01*

   Pairing-energy coefficients of neutron-rich fragments in spallation reactions

   Fei Niu🇨🇳 · Chun-Wang Ma🇨🇳

   The ratio of pairing-energy coefficient to temperature ($a_p/T$) of neutron-rich fragments produced in spallation reactions has been investigated by adopting an isobaric yield ratio method deduced in the framework of a modified Fisher model. A series of spallation reactions, 0.5$A$ and 1$A$ GeV ${}^{208}$Pb + $p$, 1$A$ GeV ${}^{238}$U + $p$, 0.5$A$ GeV ${}^{136}$Xe + $d$, 0.2$A$, 0.5$A$ and 1$A$ GeV ${}^{136}$Xe + $p$, and ${}^{56}$Fe + $p$ with incident energy ranging from 0.3$A$ to 1.5$A$ GeV, has been analysed. An obvious odd-even staggering is shown in the fragments with small neutron excess ($I\equiv N-Z$), and in the relatively small-$A$ fragments which have large $I$. The values of $a_p/T$ for the fragments, with $I$ from 0 to 36, have been found to be in a range from -4 to 4, and most values of $a_p/T$ fall in the range from -1 to 1. It is suggested that a small pairing-energy coefficient should be considered in predicting the cross sections of fragments in spallation reactions. It is also concluded that the method proposed in this article is not good for fragments with $A/A_s>$ 85\% (where $A_s$ is the mass number of the spallation system).

   ↳ nucl-thnucl-exCPC(2018)·2 citations
2. 02*

   $\eta$ and ${\eta }^{\prime }$ photoproduction with EtaMAID including Regge phenomenology

   V.L. Kashevarov🇩🇪 · L. Tiator🇩🇪 · M. Ostrick🇩🇪

   We present a new version of the EtaMAID model for $\eta$ and ${\eta }^{\prime }$ photoproduction on nucleons. The model includes 23 nucleon resonances parameterized with Breit-Wigner shapes. The background is described by vector and axial-vector meson exchanges in the $t$ channel using the Regge cut phenomenology. Parameters of the resonances were obtained from a fit to available experimental data for $\eta$ and ${\eta }^{\prime }$ photoproduction on protons and neutrons. The nature of the most interesting observations in the data is discussed.

   ↳ hep-phnucl-exnucl-thBled Workshops Phys.(2017)·1 citation
3. 03*

   Arbitrary digital pulse sequence generator with delay-loop timing

   Radim Hošák · Miroslav Ježek

   We propose an idea of an electronic multi-channel arbitrary digital sequence generator with temporal granularity equal to a single clock cycle. We implement the generator with 32 channels using a low-cost ARM microcontroller and demonstrate its capability to produce temporal delays ranging from tens of nanoseconds to hundreds of seconds, with 12 ns timing granularity and linear scaling of delay with respect to the number of delay loop iterations. The generator is optionally synchronized with an external clock source to provide 100 ps jitter and overall sequence repeatability within the whole temporal range. The generator is fully programmable and able to produce digital sequences of high complexity. The concept of the generator can be implemented using different microcontrollers and applied for controlling of various optical, atomic, and nuclear physics measurement setups.

   ↳ physics.ins-detnucl-exquant-phRev.Sci.Instrum.(2018)·9 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.