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The performance of germanium detectors for high-energy γ-rays was evaluated using a 992-keV resonance in the 27Al(p, γ)28Si reaction. The measurement was conducted at the RIKEN tandem accelerator. The energy of the excited state from the resonance was evaluated as 12540.7(2) keV. Using newly evaluated excitation energy, an energy calibration function and a photo peak efficiency of Ge detectors up to 10.8-MeV photons were deduced. Energy accuracy is achieved at 0.3 keV for the overall energy region. This reaction provides reliable energy and efficiency standards for high-energy γ-rays.

Tapered glass capillary optics was utilized to produce MeV ion microbeams at the RIKEN Pelletron facility. A microbeam of 3 MeV He ions was used to irradiate HeLa cells and demonstrated an ion track consisting of double strand break points in the cell nucleus. A new microbeam line was developed with profile measurements of 2.8 MeV H+ microbeams in the atmosphere, using image recognition and knife-edge methods. After the suppression of the halo component in the microbeam, a smaller beam size was measured to be approximately 40 μm for the irradiation distance of 1 mm, which satisfied requirements of the planned applications.

We have measured the energy of each charged particle in carbon ion beam using a transition edge sensor (TES). The TES was irradiated by carbon ion beam of 100 MeV/u in Heavy Ion Medical Accelerator in Chiba. We have measured the energy of each charged particle in the carbon ion beam. This will contribute to the establishment of a new dosimetry method of carbon ion beam for radiotherapy.

Heavy ion cancer therapy allows the tumors to destroy while sparing surrounding, healthy tissues. By controlling the incident energy of heavy ions, the penetration depth can be adjusted precisely to the tumor area. The ionizing chambers are usually used for the determination of absorbed dose in the heavy ion irradiation fields; however, uncertainty in measurement of these detectors is expected to remain by more than 5%, and this has a negative influence on the therapeutic effect. Now we began to develop the precision heavy ion beam detector applying the superconducting transition-edge sensor (TES). Using the Ir/Au-TES coupled to a tin absorber, we have succeeded to detect the helium ions which were injected from Heavy Ion Medical Accelerator in Chiba. Although pulses are fully saturated because the temperature change is beyond the transition region, the signal length reflects the incident energy of each injected heavy ion. These results indicate the possibility of the precision heavy ion energy detection applying the TES detector.

Charge deposition dependences of electron transmission through insulating PET nanocapillaries and a tapered glass microcapillary are reported and differences with HCI transmission are noted. Investigations were conducted for electrons with incident energies 500–1000 eV, corresponding to energies per charge similar to those used for HCI studies, incident on (1) an array of PET nanocapillaries (density ∼5 × 108/cm2) with diameters 100 nm in a foil of thickness 12 μm, and (2) on a tapered glass microcapillary with inlet/outlet diameters of 800/100 μm and a length of ∼35 mm. The transmission was measured for incident electrons at small sample tilt angles ranging from 0° to 5° with respect to the beam direction. For most angles, including those near zero degrees, there was an initial quiet period during which essentially no transmission was observed, followed by large rises in the transmission during relatively short periods of charge deposition before equilibrium of the transmission was reached. The resulting equilibrium was stable, blocked or had frequent oscillations depending on the incident energy and the capillary used. Observations for both capillaries show that a negative charge patch is needed to guide incident electrons through the capillaries similar to the manner in which HCIs are guided through capillaries.

We measured laser microbeam (18 µm) profiles of tilted glass capillary at wavelength 375 nm. The profile intensity, width and beam guided angle were obtained and results show guiding effect of the capillary optics.

An experimental study of electron transmission and guiding through a tapered glass capillary has been performed. Electrons were transmitted for tilt angles up to ∼6.5° and ∼9.5° (laboratory angles) for incident energies of 500 and 1000 eV, respectively. It is found that elastic and inelastic contributions give rise to distinguishable peaks in the transmitted profile. For 500 eV elastic transmission dominates the profile, while for 1000 eV both elastic and inelastic contributions are present. The transmission for both energies was studied as a function of the charge (time) deposition and found to be strongly dependent. Results suggest fundamental differences between 500 and 1000 eV incident electrons. For 500 eV the transmission slowly increases suggesting charge up of the capillary wall, reaching relative stability with infrequent breakdowns for all angles investigated. For 1000 eV for tilt angles near zero degrees the time dependent profile shows oscillations in the transmission, which never reached a stable condition, while for the larger angle investigated the transmission reached near equilibrium. Inelastic processes dominated the transmission for 1000 eV even at very small tilt angles, but was generally elastic (due to Coulomb deflection) for 500 eV even for the largest tilt angle measured.

The transmission of an ultraviolet-laser microbeam through a tapered glass capillary was investigated. We measured microbeam profiles using fluorescent beads and obtained smaller spots for smaller ...

Straight and curved glass capillaries were tested for the guiding of 8 keV Ar 8+ ion beams. The straight capillary was about 50 mm long and 0.87 mm/1.1 mm in inner/outer diameter. One of the two curved capillaries was similar, but was curved with a 270 mm radius. The other was 53 mm long, had diameters of 2.34 mm/2.99 mm, and was curved with a 150 mm radius. The corresponding bending angles of the two curved capillaries were 9.6° and 17.5°, respectively. Transmission through the straight capillary disappeared when the tilt angle was larger than 5°. The curved capillaries guided the ion beams into their corresponding bending angles, which were much larger than 5°, with transmission efficiencies of a few tens percent. This demonstrates the possibility of developing a new scheme of simple small beam deflectors and related beam optics.

Synopsis Profiles of 2.8 MeV H+ microbeam extracted from a single tapered glass capillary optics were meas-ured by two methods for a future irradiation to an outer organ of insect target. The halo component was analyzed to be 575 μm in full width at half maximum (FWHM) at a plastic tracking detector CR-39 located 1 mm down-stream of the capillary. The core component was examined by knife-edge method according to the ion energies. The profiles consisting of more energy-loss events have wider FWHM, which can be reduced by Al thin layers.

The angular (φ-) dependences of the yields of scattered ions and neutrals were measured when 8–80 keV Ar8+ ions were obliquely incident on the single-crystalline ZnO (0001) and ( 000 1 ¯ ) surfaces at small incidence angles of ψ = 5, 7, and 9° measured relative to the plane of the surface. The φ dependences of the yields had a peak near the specular reflection angle that is φ ∼ 2ψ. The maximum yields of the ( 000 1 ¯ ) surfaces at the peaks were almost twice as large as those of the (0001) surfaces at each incidence angle ψ for a given energy E. A faint difference between the two polarity surfaces was observed in the ψ-dependences of the maximum yields. The influence of the surface polarity on the scattering processes was examined by comparison with simulated results.

We report the experimental study of 1000 eV electrons transported through a tapered borosilicate glass capillary with inlet/outlet diameters of 800 μm/100 μm and a length of 35 mm. Transmission was observed for tilt angles from −9.5° to 1.0°. For tilt angles −9.5° to −4.5° the angular distributions of the normalized intensities of transmitted electrons consisted of a single peak showing stable transmission with inelastic behavior, while for tilt angles closer to zero (−4.0° to −1.0°) the spectrum consisted of two peaks also with an inelastic nature. Interestingly, when the tilt angle was within the range −0.8° to 0°, three peaks were observed, one being the direct peak with only elastic nature, and the other two showing both inelastic and elastic behaviors.

We measured resonant coherent excitation of a 2s electron of 83.3 MeV/u Fe 23+ ions planar-channeling in the ( 2 ¯ 2 0 ) plane of the silicon crystal. A silicon surface barrier detector (SSD) was used as a crystal target in order to obtain information on the ion trajectory in the channel since the energy deposit ( Δ E ) to the SSD gives information on the ion trajectories where the resonant transitions occur. For the low Δ E , i.e., near the channel center, optically allowed 2s–3p transitions were much stronger compared with other transitions. Increasing Δ E , i.e., increasing the amplitude of ion trajectory, the optically forbidden 2s–3s transition rapidly became strong. On the other hand, the optically forbidden 2s–3d transitions did not become strong as rapidly as 2s–3s transition. Furthermore, it was found that the transition energies to the n = 3 states changed with Δ E . The shifts of the transition energies were consistent with the estimation for the energy levels of the Stark-mixed n = 3 states depending on the distance from the channel center.

Microbeams of visible light were studied using a tapered glass capillary. Transmittance of laser light through capillaries with different inlet and outlet diameters was measured. About several % of the transmittance was obtained and larger than 80% was achieved in combining with an optical lens. It was found that the obtained transmittance considerably depended on the capillary shape, i.e., the taper angle. Density enhancement of the extracted beam was derived and showed a strong focusing ability for the tapered glass capillary. Propagation of visible light through the capillary was discussed.

An experimental study of 500- and 1000-eV incident electrons transmitted through a micrometer-sized funnel-shaped (tapered) glass capillary with inlet diameter 0.80 mm, outlet diameter 0.10 mm, and a length of 35 mm is reported. The properties of the electron beam transmitted were measured as a function of the emerging angle and the incident energy dependence. The angular profiles were found to be comprised of up to three peaks for both 500 and 1000 eV showing evidence for transmission going straight through the capillary without interacting with the walls (direct), as well as transmission resulting from Coulomb deflection of the electrons from a negative charge patch or by scattering from nuclei close to the surface of the capillary (indirect). The energy spectra show that elastically transmitted electrons dominate at 500 eV for increasing sample tilt angles up to \ensuremath{\sim}5.0\ifmmode^\circ\else\textdegree\fi{}, while inelastic processes dominate for 1000 eV already at tilt angles of \ensuremath{\sim}1.0\ifmmode^\circ\else\textdegree\fi{}. The angular width of the emitted electrons was found to constitute a narrow beam for direct (\ensuremath{\sim}0.4\ifmmode^\circ\else\textdegree\fi{}) and indirect (0.6\ifmmode^\circ\else\textdegree\fi{} for 500 eV and 1.0\ifmmode^\circ\else\textdegree\fi{} for 1000 eV) transmission for both energies with the widths decreasing for the largest tilt angles measured and approaching the inherent resolution (\ensuremath{\sim}0.3\ifmmode^\circ\else\textdegree\fi{}) of the electron analyzer.

Sex chromosomes are particularly interesting regions of the genome for both molecular genetics and evolutionary studies; yet, for most species, we lack basic information, such as the gene order along the chromosome. Because they lack recombination, Y-linked genes cannot be mapped genetically, leaving physical mapping as the only option for establishing the extent of synteny and homology with the X chromosome. Here, we developed a novel and general method for deletion mapping of non-recombining regions by solving “the travelling salesman problem” and evaluate its accuracy using simulated datasets. Unlike the existing radiation hybrid approach, this method allows us to combine deletion mutants from different experiments and sources. We applied our method to a set of newly generated deletion mutants in the dioecious plant Silene latifolia and refined the locations of the sex-determining loci on its Y chromosome map.

A heavy-ion beam has been recognized as an effective mutagen for plant breeding and applied to the many kinds of crops including rice. In contrast with X-ray or γ-ray, the heavy-ion beam is characterized by a high linear energy transfer (LET). LET is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependent regulated genes, whose expression level increased with the rise of LET value, were also identified. Gene ontology (GO) analysis of LET-independent up-regulated genes showed that some GO terms were commonly enriched, both 2 hours and 3 weeks after irradiation. GO terms enriched in LET-dependent regulated genes implied that some factor regulates genes that have kinase activity or DNA-binding activity in cooperation with the ATM gene. Of the LET-dependent up-regulated genes, OsPARP3 and OsPCNA were identified, which are involved in DNA repair pathways. This indicates that the Ku-independent alternative non-homologous end-joining pathway may contribute to repairing complex DNA legions induced by high-LET irradiation. These findings may clarify various LET-dependent responses in rice.

We observed a slowly and regularly oscillating transmission current through a gap (0.1 mm) of paired soda lime glass plates during an injection of a steady highly charged ion beam. The oscillation frequency was almost proportional to the injection current intensities. This phenomenon can be attributed to the charge–discharge iteration cycle with dynamic resistive switching of the glass plate. Our model calculation based on such cyclic resistive switching well reproduces the experimental observation.

An ion irradiation system in liquid has been developed using a tapered glass capillary with a thin window at the tip. Irradiation at a solid–liquid interface is interesting because it can be applied to novel analysis, radiation testing, and surface modification processes. In this study, polyethylene and polytetrafluoroethylene were irradiated with H+ ions in an aqueous solution containing acrylic acid monomers. The irradiated surfaces which were originally hydrophobic became hydrophilic due to the surface layer formed by the acrylic acid polymer.

We have developed a method to produce micro/nano meter sized beams of keV energy highly charged ions (HCIs) and MeV energy protons/He ions with tapered glass capillary optics for application of surface modifications and a biological tool called “cell surgery”, respectively. The transmission through the tapered glass capillaries with inlet diameter of 0.8 mmϕ, outlet diameter from 900 nmϕ to several tens of microns and length of about 50 mm was performed using 8/64 keV Ar 8+ beams. The transmitted beams had a density enhancement of about 10 and were guided through a capillary tilted by as large as ±100 mrad. The charge state of the beams was kept during the transmission. The combination of MeV proton/He ion beams and the capillary with a thin end window at its outlet can realize pinpoint energy deposition and three-dimensional selection of the bombarding point in an arbitrary position of a living cell or in any liquid object. We demonstrated that a real biological cell, HeLa cell with the nucleus labeled by green fluorescent protein (GFP), was irradiated with the microbeam, which was prepared by 4 MeV He 2+ entering a capillary with an end window of 7.3 μm in thickness and outlet diameter of 9.6 μmϕ. The transmitted MeV ion beams had density enhancement up to 1000 according to the capillary outlet sizes, which are applicable to various material analyses employing microbeams.

Precise measurement of neutron beta decay tests predictions of the Standard Model of electroweak interaction. The coefficient a of the antineutrino/electron angular correlation is determined by measuring the energy spectrum of the recoil protons generated in the neutron beta decay. A proton spectrometer required for this measurement demands high detection efficiency, high energy resolution and a large detection area. We have begun development of a transition edge sensor (TES) microcalorimeter for use as a low energy particle detector. To realize the large detection area we have designed a pixelated TES array incorporating a parallel biasing scheme. Our TES device consists of 4-pixels using a Au/Ti/Au trilayer film adjusted to a superconducting transition temperature of Tc ~ 380 mK. This temperature is convenient for use in a 3He cryostat with a pulse tube refrigerator. The Au films improve thermal conductivity, thereby reducing position dependent effects and allow an increased detector area.

We have measured two-dimensional images of 3.5–7 keV Ne 7+ ions guided by PET nanocapillaries as a function of the deposited charge. The transmitted ion position and shape are found to change with the intensity evolution. After saturation of the guided ion intensity, the transmission profile is nearly isotropic and its angular width amounts to about 1°, which differs from previous measurements.

We have developed a method to produce a nm sized slow highly-charged ion beam based on a self-organized charge up inside a single tapered-glass capillary. In order to investigate the characteristics of the obtained beams, the transmission of 8 keV Ar8+ beam through the capillary of 5-cm long with 800/24 μm inlet/outlet inner diameter was examined. The transmitted beam had the same size as the outlet with the beam-density enhancement of approximately 10. The initial beam was guided through a capillary tilted by as large as ±100 mrad and it still kept the incident charge. A focused ion beam of Ga+ was employed to manufacture the capillary outlet as small as several hundreds nm in diameter and fabricate a thin glass window at the capillary outlet for biological applications.

Propagation and transmission of laser beam through tapered glass capillary were investigated for light microbeams. Transmittances of laser light at 488 nm and 633 nm through capillaries were measured to be up to 15%, depending on outlet diameters. By modeling the real capillary, transmittances were calculated using taper angles obtained from shape analysis and agree well with experimental ones.

This year, a prototype of a highly sensitive beam current monitor with a High- Temperature Superconducting (HTS) SQUID and an HTS magnetic shield: HTS-SQUID monitor has been installed in the beam transport line of the RIKEN Ring Cyclotron (RRC). Unlike other existing facilities, the HTS-SQUID monitor allows us to measure the DC of highenergy heavy-ion beams nondestructively in such a way that the beams are diagnosed in real - time and the beam current extracted from the RRC can be recorded without interrupting the beam user's experiments.

K X-rays emitted from 2.1 keV/u N ions transmitted through a thin Ni microcapillary foil were measured in coincidence with a final charge state qf, using a Si(Li) X-ray detector in the cases of incident charge states of qi = 7 and 6. It was found that (1) the coincidence X-ray yield for (qi, qf) = (7, 6) decreased faster than those for other (qi, qf) combinations, (2) the coincidence X-ray yields did not depend on the number of K-shell holes of the incident ions but on the final charge state qf.

We have made coincidence measurements between L X-rays and final charge states of highly-charged Ar ions passing through a Ni microcapillary thin foil to study the formation and relaxation processes of hollow atoms. By using N6+ projectile ions which have single K-shell hole, Ninomiya et al. [Phys. Rev. Lett. 78 (1997) 4557] showed the existence of long lived excited states formed by multiple electron transfer from a Ni microcapillary thin foil. To further study the formation and relaxation dynamics, such experiments were extended to Ar ions with multiple L-shell holes. The yields of L X-rays from Ar ions, which have one stabilized-electron, decrease faster than those from ions with multiple stabilized-electrons, when the projectiles have multiple inner shell holes.

We observed resonant coherent excitation of the 2s electron to the n = 3 states of 83.5 MeV/u Li-like Fe23+ ions planar-channeling in the ( 2 2 ¯ 0 ) plane of a Si crystal. A survival fraction of the Li-like ions was measured as a function of the angle between the incident beam and the [0 0 1] axis. Clear resonance dips corresponding to the transitions of a 2s electron to all the n = 3 states were observed. The transition of each resonance dip was identified by comparing with spectroscopic data. The resonance dips at the transition energies corresponding to the optically forbidden 2s1/2–3s1/2, 2s1/2–3d3/2 and 2s1/2–3d5/2 transitions were observed as well as the resonance dips at transition energies corresponding to the optically allowed 2s1/2–3p1/2 and 2s1/2–3p3/2 transitions.

A superconducting tunnel junction (STJ) is very attractive for use in high-energy-resolution photon detectors because of its small energy gap. To detect a single photon, the Josephson current of the STJ has had to be suppressed by an external magnetic field. We demonstrated an on-chip coil-integrated STJ photon detector, which excludes the external magnetic field, allowing a small device size. A normal-distribution function shape was adopted for the superconducting electrodes, which makes the magnetic field supplied to the STJ small. We devise a new superconducting photon detector by combining the above techniques. A new Josephson switching gate is also integrated on the same detector chip in order to drive an on-chip integrated coil by a persistent superconducting current. This behavior was confirmed experimentally using the technology of the fabrication process of the Nb/Al-AlOx/Nb Josephson tunnel junction.

To detect weak X-rays with a high-resolution spectrometer, a charge-coupled device was operated in a single X-ray photon detection mode. A procedure to effectively identify single X-ray was established. In the case of 2.3 keV/u N7+ and Ne9+ incidence, X-rays emitted from ions transmitted through a Ni microcapillary target were measured with the spectrometer using the procedure of the single event mode. The signal-to-noise ratio was improved by using the single photon counting method.

The resonant coherent excitation from a 1s state to n=2 states of 94 MeV/u Ar17+ ions channeling in the (2 2 0) plane of a Si crystal was observed as the decrease of the survival fraction of Ar17+. Three resonance dips of survival fraction were clearly seen. The resonance profile is attributed to the spin–orbital interaction, the position-dependent Stark effect, the position-dependent transition probability and the position-dependent ionization probability of excited states. The estimated experimental resolution of measurement of the resonance profile is comparable to the width of the narrowest resonance dip (∼1.5 eV FWHM) or less.

On-chip coil integrated superconducting tunnel junction (OC 2 -STJ) has been demonstrated for high performance X-ray detector. The STJ was fabricated by an improved fabrication technique based on a high quality Nb/Al/AlO x /Nb junction technology. The STJ shows high quality current–voltage characteristics with an ultra-low leakage current of a few nA at 0.4 K for 100 μm ×100 μm junction. Typical critical current of the coil was achieved more than 50 mA for 2 μm line width, which can generate a magnetic field of about 10 mT into the STJ. It was found that the OC 2 -STJ successfully responded to the irradiated 5.9 keV X-ray.

A superconducting tunnel junction (STJ) is a newly developed X-ray detector which has advantages of not only high energy-resolution but also timing information and high counting-rates. The STJ fabricated in RIKEN has a layered structure of Nb (200 nm-thick, lower electrode)/Al (50 nm)/AlOx/Al (50 nm)/Nb (150 nm, upper electrode). Its sensitive region has an area of 100×100 μ m2. The output signals were amplified by either a charge-sensitive amplifier or a SQUID amplifier. We used the STJ to measure X-rays emitted in collisions of highly charged ions with various solid targets. The ions used were Ne, O and Ar of 10 kV/q extracted from an ECR ion source at RIKEN. The X-ray spectra from 500 to 900 eV were obtained with an energy-resolution of 20–30 eV at a counting-rate higher than 500 counts/s.

We are developing an energy-dispersive detector for UV and visible photons that uses superconducting tunnel junctions (STJs) with Al trapping layers. As a first step to achieve this, we evaluated the performance of the detector for extreme ultraviolet (EUV) photons by using a synchrotron radiation facility. We achieved an energy resolution of FWHM=17.8±0.6 eV (including electrical noise of 17.6±0.2 eV) for 55 eV EUV photons with a 100×100 μm2 STJ. The electrical noise was the main component of the energy resolution. We achieved the electrical noise of FWHM=2.1±0.1 eV for a 20×20 μm2 STJ by replacing the cables connecting the STJ to a preamplifier operated at room temperature. A stronger signal resulting from a thinner tunnel barrier will lead to better energy resolution for detecting UV and visible photons.

Superconducting tunnel junctions (STJs) are applicable to as photon detectors with an energy resolution and a high photon-counting rate. The absorption of a photon in the superconductor of the STJ generates a number of quasiparticles that is proportional to the photon energy. Especially for soft X-ray and extreme ultraviolet (EUV) applications, STJs have good performance because of their high absorption efficiency below 1 keV. We are developing an energy-dispersive photon detector for EUV radiation using STJs with Al trapping layers. We evaluated the performance of the detector for EUV photons by using the Synchrotron Facility at KEK-PF in Tsukuba, Japan. We achieved an energy resolution of FWHM=18 eV (including the external noise of 17.6 eV) for 55 eV EUV photons with a 100 × 100 μ m 2 STJ. We present details of the junction design and discuss our experiments and the results.

An estimation method of micro-meter sized laser profile created by the laser beam transmission through a tapered glass capillary is developed for the target sight-on system of ion microbeam irradiation to living cells. In our system, both the laser and the ions are designed to be transmitted through the same capillary so that the laser spot is surely on the ion track. By selecting the excitation light of a fluorescent protein in cell nucleus, the fluorescent volume can be confirmed as the targeted area.

Recently, many studies have been reported on microbeam production of keV-MeV accelerated ions using tapered glass capillaries. However, few studies about visible light with the glass capillary have been reported up to now. Preferable sizes of microbeams can be obtained by the glass capillary which may provide a new method for focusing light and for producing microbeams of visible light in addition to conventional optical lenses. We report experimental study of propagation of visible light through tapered glass capillaries towards microbeams.

We present a novel facility for micro-irradiation of living targets with ions from a 1.7 MV tandem accelerator. We show results using 1 MeV protons and 2 MeV He(2+). In contrast to common micro-irradiation facilities, which use electromagnetic or electrostatic focusing and specially designed vacuum windows, we employ a tapered glass capillary with a thin end window, made from polystyrene with a thickness of 1-2 μm, for ion focusing and extraction. The capillary is connected to a beamline tilted vertically by 45°, which allows for easy immersion of the extracted ions into liquid environment within a standard cell culture dish. An inverted microscope is used for simultaneously observing the samples as well as the capillary tip, while a stage-top incubator provides an appropriate environment for the samples. Furthermore, our setup allows to target volumes in cells within a μm(3) resolution, while monitoring the target in real time during and after irradiation.

The formation and relaxation processes of hollow atoms and related excited states of ions produced with a Ni microcapillary thin foil have been studied employing various experimental techniques. The first stage of the charge transfer from the surface to the ions was studied by using visible light measurements. On the other hand, X-ray measurements revealed the core electronic configurations of ions at the last moment of the hollow atom evolution. The overall feature of the electron capture processes in the capillary was given by the charge state distribution measurements.

We succeeded in separating the STJ upper electrode events from other electrode events. This study is for X-ray spectroscopy of slow ions. With a SQUID amplifier, it is clearly seen that the upper electrode signal has a sharp peak with a narrow base, while the other has a relatively gentle peak with a wide base. The difference in signal width was used to separate the upper electrode events from other electrode events. Then the X-ray spectroscopy of slow highly charged ions was carried out at RIKEN. The results are shown here.

The pulse height spectra of the substrate phonon events obtained with superconducting tunnel junctions (STJs) were examined. We compared the spectra for STJs with and without a 50-nm-thick buffer layer of aluminum-oxide on the sapphire substrate under X-ray illumination. We found-that the spectral difference was concentrated in the high-energy tail of the component, corresponding to the events absorbed within a thin skin. The effective thickness of this skin was estimated to be about 3 /spl mu/m by using the amount of difference in the spectra. We explain that the spectral difference could be caused by the selective attenuation of high-frequency phonons in the substrate and buffer layer.

The superconducting tunnel junction (STJ) is one of the most promising devices to use as a fast detector for heavy ions. The energy deposited due to the passage of a heavy ion through an STJ forms a region called a hot spot, where the superconductivity of the region is broken. As a result, a reduction of the critical current (I/sub c/) in the STJ occurs. If the bias current exceeds this reduced I/sub c/, the output voltage from the STJ switches from 0 V to its gap voltage, which is recognizable as a signal due to the heavy ion passage. Nb-based STJs were fabricated for this heavy ion detector and an experiment was performed at the RIKEN Ring Cyclotron Facility to investigate the response to heavy ions. Instantaneous switching to the voltage state of the STJ in response to the decrease in I/sub c/ induced by a heavy ion beam was successfully observed by introducing /sup 40/Ar particles with a kinetic energy of 95 MeV/nucleon into the STJ.