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This paper discusses the hypervelocity impacts of micrometeoroids and orbital debris (MMODs) on inverted metamorphic triple-junction (IMM3J) and perovskite solar cells, which are much thinner than conventional triple-junction (3J) solar cells. We experimentally found that IMM3J solar cells can suffer from short-circuit faults due to hypervelocity impacts of MMODs unlike conventional 3J cells, and determined the projectile diameters and velocities that could cause them using a model proposed by Burt. No short-circuit mode was identified in perovskite solar cells, but they had open-circuit faults several days after the hypervelocity impact experiment, which are possibly attributed to the decomposition of the perovskite crystal by moisture in the air due to the broken seal.

The response of the lead zirconate titanate (PZT) element to an irradiated 20 MeV electron beam was studied. Both the resonant and antiresonant frequencies of the PZT element were measured under irradiation, and then the variation of the electromechanical coupling factor was investigated. It was found that the coupling factor linearly decreased with increasing beam energy absorbed in the PZT element, whereas the surface temperature remained constant. We propose a dosimeter based on piezoelectric PZT.

The variation of the electromechanical coupling factor of lead zirconate titanate (PZT) was studied using a piezoelectric PZT disk exposed to a 400 MeV/n xenon beam. The resonant and antiresonant frequencies were measured in pairs by an impedance analyzer in situ manner. A systematic behavior of the pairs resulted in a decrease of the coupling factor. It was found that the coupling factor linearly decreased with increasing integrated beam energy incident on the PZT disk while its surface temperature was equilibrium at room temperature. We discuss a possible PZT-based radiation detector for practical use in a high-radiation field.

Acoustic signals produced by irradiating ethanol with 400 MeV/n Xe ions were experimentally studied. The signals were detected by an array of piezoelectric PZT elements. They were categorized into two types: one was a primary product of the incident fast ions; the other was a secondary product resulting from an energy release to ethanol just before the ions stopped and subsequently diffused in ethanol. A possible mechanism of the secondary signal is discussed in association with the Bragg peak formation.

To develop a new radiation detector, the characteristics of piezoelectric lead zirconate titanate (PZT) are currently being studied using a 400 MeV/n xenon (Xe) beam. In this study, the response of the PZT element to the pulsed beam was investigated by changing the beam intensity. It was found that the time distribution of the Xe ions in the pulse duration must be taken into account to understand the formation of the output signal that appeared on the PZT element.

A piezoelectric lead–zirconate–titanate (PZT) element was exposed to a 400 MeV/n xenon beam and the radiation effect on the element was studied as a variation of resonant and antiresonant frequencies by the resonance method. A possible effect of heating the element on the resonant frequency was avoided by using data obtained while the temperature of the element was kept constant. Consequently, the variation of the resonant frequency was empirically represented by a simple function of the amount of accumulated energy in the element. We therefore discuss the piezoelectric PZT element as a potential detector for high-level radiation. We point out that a piezoelectric equation including the heat term is required to explain the experimental results.

The variation of the electromechanical coupling factor (ECF) was measured by bombarding a piezoelectric lead zirconate titanate (PZT) element with 400 MeV/n xenon ions. The element was exposed to energies up to 104 J, during which time the ECF was observed by the resonance method. The ECF gradually decreased with the energy accumulated during irradiation, and its behavior was scaled with an empirical formula. This decrease suggests that the piezoelectric quality deteriorated; hence, the sensitivity of the PZT radiation detector was considered to be degraded as well. The variation ultimately originated in resonance-associated processes. A potential detector suitable for use in severe-radiation environments was discussed.

The influence of a thermal reflector on the sensitivity of a lead–zirconate–titanate element is studied by bombarding the element with hypervelocity microparticles. The reflector is a 60-µm-thick layer made of polyimide resin that coats the surface of the element. By applying the fast Fourier transform method to data analysis, impact information is obtained through the fundamental resonant component. As a result, the sensitivity of the element is considerably reduced by the reflector. In addition, it is found that the sensitivity is substantially position-independent.

A possible position dependence of the signal amplitudes generated by a piezoelectric lead–zirconate–titanate (PZT) detector was studied by bombarding the PZT element with hypervelocity microparticles. The detector was equipped with a set of asymmetrically arranged electrodes. The characteristic features of the element were analyzed using the amplitudes of the fundamental resonant component caused by collisions. As a result, the sensitivity of the element measured with direct collisions onto the collector was found to be one order of magnitude greater than that in the external area of the collector.

We have obtained the ratio of the transverse diffusion coefficient to the mobility of electrons multiplied by the elementary charge, in Xe and Xe+H2 under electric fields at a higher pressure of 1 MPa in comparison with those in preceding experiments. The results show that the density effect (nonlinear effect) of the ratio in both pure Xe and Xe+H2 is ≤15% below 1 MPa over the reduced electric field range from 0.08 to 0.6×10-17 V·cm2. We also found that the diffusion of an electron swarm is suppressed by adding trace amount of hydrogen to high-pressure xenon gas. We discuss the application of Xe+H2 gas to a new gamma-ray camera.

Photon-stimulated desorption (PSD) of CO from Si single crystal is studied carefully by the throughput method. The photodesorption yield of Si single crystal is lower than that of OFHC copper. To investigate the effect of impurities in Si, stable isotope 13C is chosen as an impurity. 13CO is hardly detected in the outgas due to PSD from 13C-implanted, Si single crystal. It is concluded that carbon in Si single crystal is not desorbed in the PSD process.

Ion trapping in a single bunch operation was experimentally studied at the Photon Factory storage ring at KEK. Ions were trapped even in the single bunch beam at a stored current of 38 mA. This is contrary to the standard ion-trapping theory, which predicts that the motion of ions is unstable in the electron beam orbit under the present experimental condition. In this experiment, bremsstrahlung produced by collisions between the electron beam and trapped ions was observed. Shifts in the betatron tunes also suggested the presence of ions.

The I-V curves of microbridges of uniform thickness and given geometry are calculated, and the results are in good agreement with those of Pb thin-film microbridges with the corresponding geometries. Using this result, we have designed a microbridge of new geometry with metallic balls at the edges of the bridge part which prevent the normal state from expanding into the electrodes when the electric current is increased. A very simple technique for fabricating this new microbridge is described. With the new microbridge, more Shappiro steps have been observed than with conventional microbridges, up to a voltage as high as 0.7 mV.

The shield effect of a pipe is estimated as a function of its dimensions. Si Single crystal is chosen as the pipe material based on experimental results showing that its outgassing rate is lower than that of SUS 304 stainless steel. The Si single-crystal shield-pipe effectiveiy prevents environmental PSD and is a powerful tool for precise PSD measurement of low-PSD materials.

To make a thin-film Pb microbridge durable against heat cycles, we coated thin Al film over a variable thickness Pb microbridge. It showed no detectable change in its electrical properties, critical current or normal resistance after 20 heat cycles and preseration for 250 hours in a humid environment.

A Pyrex glass surface is subjected into collision with molecular beams of di-2-ethyl-hexyl phthalate (DOP). Temperatures of the glass and of the molecules are controlled in a range 100°C~160°C. The molecules that initially impinge on a thoroughly outgassed surface form a tight adsorption layer 1.1~1.4×1014 molec./cm2 in density (first layer). The adsorption time τ of the molecules constituting the first layer is too long to measure. For the surface on which the first layer has formed, however, τ decreases with time and approaches a final value: τ=5×10-12exp (20×103/RT) s, when both the molecular beam and the glass surface are kept at temperature T (R: gas constant). By using the adsorption time obtained at various temperatures of the target and impinging molecules, the thermal accommodation coefficient is estimated to be 0.2~0.3 for the first layer. These results jointly indicate that relaxation effects are important in the adsorption of DOP on Pyrex glass.