The frequency distributions of the lineal energy, y, of 160 MeV proton, 150 MeV/u helium, and 490 MeV/u silicon ion beams were measured using a wall-less tissue equivalent proportional counter (TEPC) with a site size of 0.72 µm. The measured frequency distributions of y as well as the dose-mean values, y(D), agree with the corresponding data calculated using the microdosimetric function of the particle and heavy ion transport code system PHITS. The values of y(D) increase in the range of LET below ~10 keV µm(-1) because of discrete energy deposition by delta rays, while the relation is reversed above ~10 keV µm(-1) as the amount of energy escaping via delta rays increases. These results indicate that care should be taken with the difference between y(D) and LET when estimating the ionization density that usually relates to relative biological effectiveness (RBE) of energetic heavy ions.

The frequency distribution of the lineal energy, y, of a 290 MeV/u carbon beam was measured to obtain the dose-weighted mean of y and compare it with the linear energy transfer (LET). In the experiment, a wall-less tissue-equivalent proportional counter (TEPC) in a cylindrical volume with a simulated diameter of 0.72 microm was used. The measured frequency distribution of y as well as its dose-mean value agrees within 10% uncertainty with the corresponding data from microdosimetric calculations using the PHITS code. The ratio of the measured dose-mean lineal energy to the LET of the 290 MeV/u carbon beam is 0.73, which is much smaller than the corresponding data obtained by a wall TEPC. This result demonstrates that a wall-less TEPC is necessary to precisely measure the dose-mean of y for energetic heavy ion beams.

The fragment production excitation functions of 12 C interacting with carbon nuclei were measured in the energy range of 100-400 MeV/u. To measure cross sections as excitation functions, fragments produced from a thick carbon target bombarded with a monoenergetic 12 C ion beam were detected by a telescope detector placed behind the target. By this measurement, eight isotopes-11 B, 10 B, 10 Be, 9 Be, 7 Be, 8 Li, 7 Li, and 6 Li-were identified, and the energy dependence of their production cross sections in the few 100 MeV/u range was obtained. Based on the measured cross sections, the JAERI quantum molecular dynamics model was updated to incorporate the mechanisms particularly important for peripheral collisions. The improved version of the model coupled with a statistical decay model reproduces the measured data typically within a few 10% of difference.

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attention based on their unique properties such as flexibility, electrical and thermal conductivities, and enhanced p-type [6,9] and modified n-type [10] semiconductor characters. [2,11,12] In low-temperature solution-processable device technologies, such convenient and low energy-consuming processes have prompted exhaustive wide-field research. [13][14][15] Environmentally friendly aqueous dispersion solutions of single-walled CNTs (SWNTs) are industrially applicable; however, we suffer from dispersant molecules seriously insulating electrical communication on solution-processed SWNT film networks. Rinzler et al. overcame the drawback by a breakthrough filter-transfer method using a mixed cellulose ester (MCE) membrane. The filtrated ultra-thin SWNT films were transferred onto substrates by the dissolution removal of MCE (Figure 1, Method A). [16] Jin et al. reported that a floating method of a similarly filtrated SWNT thin film apart from MCE, and the as-floated SWNT film was picked up on a substrate (Method B). [17] See-through perovskite (PVK) solar cells have been successfully prepared using top-contact SWNT thin films [18,19] by a dry filter-transfer method using MCE membranes reported by Kauppinen et al. [20] Simply structured crystalline Si-SWNT heterojunction solar cells have been prepared by the solution-processed [21][22][23][24][25][26][27][28] and dry filter-transfer [29][30][31][32] methods with increasing photo-conversion efficiencies up to ≥17%. [25,31,33,34] See-through solar cells are indispensable for state-of-the-art tandem devices combined with crystalline Si solar cells driven by visible and near IR lights. [35,36] The stability of CNTs against chemical corrosion is a fascinating feature as a top-contact electrode on the PVK layers. The high-conductivity p-type semiconductor character of CNTs with the ≈5 eV work function realizes hole-transport layer-free PVK solar cells. [2,[37][38][39] Therefore, the discovery of a convenient solution-processable technology for preparing top-contact thin films of SWNTs using their aqueous dispersion solutions is key to achieving all solution-processed photovoltaic cells that exclude evaporated metal electrodes and expensive p-type organic semiconductors; however, PVK layers are sensitively decomposed by water, some hydrophilic solvents, and some dissolved chemicals. Furthermore, solution-processable p-type doping technologies of SWNT thin films are crucial Filter-transfer methods of single-walled carbon-nanotube (SWNT) thin films have been widely employed to fabricate state-of-the-art electronics and photonics devices with highly transparent and conductive electrodes; however, a challenge remains for all solution-processable technologies to overcome substrates' destruction due to their solvent incompatibility. Here, an advanced method of transferring SWNT thin films onto arbitrary material substrates by adopting chemically stable and flexible polytetrafluoroethylene (PTFE) membranes is reported. Filtrated SWNT thin films on PTFE membranes (PTFE@SWNTs) pres...