Ken-ichi Nogami

Dokkyo Medical University | DMU

Mercury Dust Monitor will be on board the Mercury Magnetosphere Orbiter of BepiColombo and will perform the first in situ dust detection in Mercury's orbit.

Mercury Dust Monitor (MDM) onboard the Mercury Magnetosphere Orbiter (MMO) will observe dust particles in orbit around Mercury during 1 year as nominal operation. In this paper, we report an overview of our instrument onboard the Bepi-Colombo MMO.

The Mercury dust monitor (MDM) will be the BepiColombo/Mercury magnetospheric orbiter (MMO) and be operated to clarify the dust environment around Mercury. The MDM employs lightweight and heat-resistant piezoelectric ceramic sensors made of lead zirconate titanate (PZT). This paper describes the current status of MDM development and ground calibrat...

To clarify the dust environment around Mercury (0.31-0.47 AU), we have been developing Mercury Dust Monitor (MDM) to be onboard Mercury exploration mission BepiColombo. MDM will measure the flux and momentum of the interplanetary meteoroid complex.

This paper describes our future observation of the dust environment around the Moon by the Lunar Dust Monitor (LDM) to increase our knowledge regarding how the dust inflow and outflow contribute to lunar surface materials. Dust observation in lunar orbit is of great significance to better understand the source of supply of lunar materials, the evol...

Effect of Heating and Cooling on the Piezoelectric Properties of a PZT Sensor for Mercury Dust Monitor

A dust particle detector is proposed to be onboard the orbiter of SELENE-2 mission. We summarize the significance of circumlunar dust and report an overview of our instrument proposed to accompany the SELENE-2 mission.

We have developed a light-weight and large-area impact-ionization dust/debris detector, which we call IID. This detector consists of a gold plated metal target and two grids. Ratio of mass/volume of this parallel-plate type of detectors is simply proportional to the target area. Therefore, we can fulfill the requirements, i.e. “effective dust measu...

In order to clarify the dust environment around Mercury, we have proposed that the Mercury dust monitor (MDM) should be onboard the BepiColombo/Mercury magnetosphere orbiter (MMO). The main objective of the project is to obtain new data on the flux and momentum of the interplanetary meteoroid complex near Mercury (0.31–0.47 AU). The MDM uses lightw...

In-situ measurement of dust particles in space is important to study the origin or dust particles as well as space debris. Impact-ionization dust detector can supply mass and velocity information of impacting dust particles through the shape of charge signals of impact-generated plasma. Here we have tested plane-parallel type detectors with a targe...

A cosmic dust monitor for use onboard a spacecraft is currently being developed using a piezoelectric lead zirconate titanate element (PZT). Its characteristics of the PZT sensor is studied by ground-based laboratory impact experiments using hypervelocity particles supplied by a Van de Graaff accelerator. The output signals obtained from the sensor...

A cosmic dust detector for installation on a satellite is currently being developed using piezoelectric lead zirconate titanate (PZT), which can possess both functions of the collector and the transducer. The characteristics of the PZT detector have been studied by bombarding it with hypervelocity particles supplied by a Van de Graaff accelerator....

A cosmic dust detector is currently being developed using a piezoelectric lead zirconate titanate (PZT) element. The characteristics of the multilayered detector (MD), which was composed of one hundred PZT disks, were investigated by bombarding it with hypervelocity iron particles supplied by a Van de Graaff accelerator. It was confirmed that there...

The detector characteristics of a pentagonal element were studied by colliding it with hypervelocity micro-particles. A charge-sensitive amplifier was developed for the element of its capacitance ∼10 nF. The output amplitudes were expressed as a linear function of the momentum at collision. Empirical formulas obtained from on-ground experiments cou...

A cosmic dust detector using piezoelectric lead zirconate titanate (PZT) is currently being developed for use onboard a spacecraft for the BepiColombo mission. The characteristics of the PZT detector were studied by carrying out hypervelocity impact measurements with iron particles supplied by a Van de Graaff accelerator. The measurements with part...

The temperature recorded immediately after hypervelocity collision of microparticles comprising iron and nickel with a silver-coated piezoelectric plate was analyzed using photomultipliers of different spectral response characteristics. The conversion rate between the velocity and temperature is estimated to be ~900 K/km/s in the velocity range of...

A cosmic dust detector for use onboard a satellite is currently being constructed from piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector were studied by bombarding it with hypervelocity iron particles, which were supplied by a Van de Graaff accelerator. There was a linear relationship between the rise time of the...

A cosmic dust detector for use onboard a satellite is currently being developed by using piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector have been studied by bombarding it with hypervelocity iron (Fe) particles supplied by a Van de Graaff accelerator. One central electrode and four peripheral electrodes were pla...

The propagation of transverse waves generated acoustically in a piezoelectric element by colliding it with hypervelocity microparticles was studied. The propagation times were measured by a set of multiple electrodes on the surface of the element. The coordinates that the particles struck were determined by combining the propagation times and the v...

In-situ measurement of dust and small debris particles in space is important to study the origin or those particles. Especially to examine the time variation of dust/debris flux, relatively large sensor aperture (> 500cm2 ) is necessary for dust/debris measurement at LEO. We have been developing light-weight large-area dust detectors for space. Imp...

The BepiColombo mission is planned to explore Mercury. We have proposed Mercury Dust Monitor (MDM) onboard the satellite to clarify the dust environment around Mercury. The MDM comprises two parts; sensor and electronics. The former is designed to set on the outer wall of the satellite for detection of the cosmic dust. It is fabricated by a piezoel...

Piezoelectric lead–zirconate–titanate (PZT) elements were studied by directly bombarding hypervelocity silver and iron particles in the velocity range of 2–63 km/s. This report focuses on the concept of “immediately after collision”. This concept was realized in the leading part of a pulsed signal that exhibited no effects due to reflection. The si...

Hypervelocity collisions of microparticles with a lead-zirconate-titanate piezoelectric element are examined. The waveforms thus obtained depend on the velocities during collision, and are classified into three categories. In particular, the first cycle of the signal observed immediately after collision is essential to obtain information on the imp...

Mars Dust Counter (MDC) is an impact-ionization dust detector on board Japanese Mars mission NOZOMI. NOZOMI was launched on July 4th (3rd at UT) 1998. After the change of orbital plan, NOZOMI performed interplanetary observation for 4 years. Due to an electronic trouble caused by intense solar flare, data telemetry from NOZOMI was stopped and ISAS...

Ferroelectric lead zirconate titanate (PZT) elements were studied by directly bombarding them with hypervelocity silver particles. The mass and velocity of these hypervelocity silver particles ranged from 1 to 80 pg and 2 to 6 km/s, respectively. This report examines the pulsed signals observed immediately after collision. The first cycle of the pu...

A response from piezoelectric lead-zirconate-titanate elements was investigated by bombarding them with hypervelocity iron particles. The observed signal form was clearly dependent on the particle velocity during collisions. The signal form exhibited oscillations for particle velocities less than 6 km/s, whereas it changed drastically into a solita...

Piezoelectric lead-zirconate-titanate was studied by bombarding with silver particles in the mass range from 2 to 100 pg, and the velocity range from 2 to 8 km/s. Output signals were uniquely identified on impact. It was found that incident energies above 100 nJ were measured unambiguously by a single lead-zirconate-titanate element. The detector c...

Impact ionization plasma detectors are commonly used for cosmic dust research on board spacecraft. There seems to be no scientific background on their shape, area, and applied high voltage; they are determined empirically. To design a dust detector having large aperture and lightweight to collect dust effectively for the future mission, we are to s...

Installed on peripheral plates of the Bepi Colombo MMO spacecraft, the Mercury Dust Monitor (MDM) is an array of light-weight, heat resistant, piezo-electric momentum sensor to determine incident timing, momentum, and crude incoming direction of hypervelocity impact micro particles around Mercury. It has two major scientific interest, flux and orig...

A lead-zirconate-titanate (PZT) element was studied by bombarding silver particles in the mass range from 1 to 100 pg, and the velocity from 2 to 6 km/s. Output signals were uniquely identified on impact and characterized by Fourier analysis. It was found that incident energies above 100 nJ were uniquely determined by a single PZT element. We discu...

This paper reports the impact craters formed by Ag microparticles impacts, comparing withthe TOF-MS (Time-Of-Flight Mass Spectrometer) spectra obtained simultaneously. The TOF spectra suggested that ions were hardly produced on Al target compared to Mo and Au targets. To determine the reason for this and to select the best material that ionizes the...

Mars Dust Counter (MDC) is a light-weight (730g) impact-ionization dust detector onboard NOZOMI, a Japanese Mars mission, which was launched on July 4th 1998. The main aim of MDC is to detect the predicted Martian dust rings/tori. It can also cover velocitymass ranges of interplanetary and interstellar dust particles. By August 2000, MDC had detect...

We present the computer simulation design and calibration experiments of an impact-ionization dust analyzer with a new optical system of TOF-MS (Time-Of-Flight Mass Spectrometer). A TOF-MS with curved potential ion mirror has been developed to be on board spacecraft for in-situ dust analysis. An ion mirror with curved potential proved to increase m...

In situ measurement of interplanetary and interstellar dust particles by Mars Dust Counter (MDC) is reported here. MDC is a light-weight impact-ionization dust detector on board Japanese Mars mission NOZOMI, which was launched on July 4th 1998. In four years between July 1998 and April 2002, MDC has detected more than 100 dust impacts. In November...

The Mars Dust Counter (MDC) is an impact-ionization dust detector on board the Japanese Mars mission NOZOMI, which was launched on 1998-07-04. It is an improved type of MDC-HITEN and MDC-BREMSAT and has three detection channels (electron, iron, and neutral) to discriminate noise signals from impact signals. The main aim of the MDC is to measure dus...

Mars Dust Counter (MDC) on board NOZOMI has detected more than 90 dust impacts in three years. In interplanetary observation from 1999, MDC has detected about 60 interplanetary particles moving around the sun and several interstellar dust particles.

To clarify the dust environment around Mercury and its orbit, we have proposed to install The Mercury Dust Monitor(MDM) on the Bepi Colombo MMO. The scientific interests are to obtain the new data of the flux and origin variations of interplanetary meteoroid complex inside 1 AU, as a function of the heliocentric distance, and the first-ever in-situ...

Mars Dust Counter (MDC) is a dust detector of impact ionization type on board Japanese Mars mission NOZOMI. NOZOMI was launched on July 4th (3rd at UT) 1998. Due to a problem at the powered fly-by with the Earth on 20th December 1998, NOZOMI orbital plan was changed significantly. From December 1998 to December 2002 for five years, NOZOMI takes ecc...

Detector characteristics of disk-shaped piezoceramic elements were studied by irradiating with silver and carbon microparticles. A mass of particles ranged from 0.01 to 100 pg, and whose velocity from 2 to 20 km/s. We observed characteristic pulse signals when the particles were collided with the element. Carbon projectiles generated a bipolar-type...

In-situ dust detectors have been calibrated by dust electrostatic accelerators that can accelerate projectiles to expected mass and velocity ranges of space debris and micrometeoroids. Unfortunately, In Japan, there was no such a facility dedicated to space science research until our research group was established a few years ago. Therefore, we hav...

In order to analyse the elements of dust particles in space, we have been developing a reflectron-type dust TOP-MS (Time-Of-Flight Mass Spectrometer) with a curved electric field. Now we have done performance experiments of our device by impacting hypervelocity microparticles with a Van de Graaff accelerator at HIT (High Fluence Irradiation Facilit...

Mars Dust Counter (MDC) is a light-weight impact-ionization dust detector on board Japanese Mars mission NOZOMI, which was launched on July 4th 1998. The main aim of MDC is to detect dust particles around Mars and reveal the distribution of the martian ring or torus of dust from Phobos and Deimos. In three years between July 1998 and June 2001, MDC...

We report a case of intramedullary spinal tuberculoma in a girl aged 2 years and 6 months. At the age of 18 months, the patient was hospitalized for 2 months with tuberculous meningitis. Tuberculomas then appeared in the thoracic spinal cord, and the patient developed paraparesis despite continuation of chemotherapy. Spinal magnetic resonance imagi...

A microparticle (dust) ion source has been installed in the 3.75 MV Van de Graaff electrostatic accelerator and a new beam line for microparticle experiments has been built at the HIT facility of Research Center for Nuclear Science and Technology, the University of Tokyo. Microparticle acceleration has been successful in obtaining expected velociti...

A 12-month-old girl presented with fever and vomiting. Cerebrospinal fluid (CSF) examination revealed an increase of mononuclear cells and Mycobacterium tuberculosis. Magnetic resonance imaging (MRI) taken two months after the onset showed cerebral infarction in the left basal ganglia, tuberculoma in the interpeduncular cistern and brain atrophy. T...

Patients with ischemic heart disease are often complicated with cerebrovascular disease. The purpose of this study is to examine the usefulness of Xe-CT CBF study in patients with cerebral arterial occlusive disease before cardiac surgery with cardiopulmonary bypass. This study was carried out in 11 patients suffered from ischemic heart disease wit...

Recent progress in cardiopulmonary resuscitation techniques improved the survival rate of patients with acute cardiopulmonary disturbances. However, severe cerebral complications remained frequently in patients who survived the acute stage. Early prediction of cerebral prognosis is important to optimize the management of these patients. We examined...

We report a case of optic glioma with bilateral optic atrophy. A 3-year-old girl presented with vomiting and left hemiparesis. She had hypothalamic dysfunction, right ptosis, right monocular nystagmus, left facial palsy, left hemiparesis, and left pes adductus. Neuroimaging studies showed obstructive hydrocephalus with a large suprasellar calcified...

We designed a new dust analyzer with TOF (time-of-flight) mass spectrometer on board spacecraft, and perfomed preliminary experiments with pulsed IR laser irradiation and high velocity particles impact as ion source.

A 3.75 MV Van de Graaff electrostatic accelerator was modified to accelerate microparticles, and acceleration testing was carried out. The velocity range is 1-20 km/s for micron or sub-micron particles.

In order to unveil the presence and characteristics of Martian dust ring/torus, Mars Dust Counter (MDC) is aboard ISAS's spacecraft PLANET-B, which will be launched in 1998 summer and investigate the upper atmosphere and surrounding environment of Mars between 1999 and 2001. MDC PLANET-B is an improved version of impact-ionization dust detectors ab...

Direct measurements of dust particle in space have unveiled characteristics of interplanetary and interstellar dust particles. In addition to the approved PLANET-B MDC (Mars Dust Counter) in 1998, two dust detectors with mass spectrometry are proposed for Japanese future space missions: lunar and asteroid missions. A lunar orbiter mission is planne...

To survey the existence forms and existence patterns of Cr and Ru in high-temperature condensate, we have continued to carry out elemental analyses of primitive meteorites particularly acid insoluble fractions and metal phases from them. In addition, condensation calculation, which assume ideal solid solution in the multicomponent alloy, by using t...

We are planning to carry out systematic isotopic investigations of Ru, Mg, etc., in primordial samples. The investigations will be pursued in the context of a study of the pre-history of the solar system. It is hoped that the study will yield direct evidence for processes of nucleosynthesis in the pre-solar stage and detection of extinct radioactiv...

The Munich Dust Counter (MDC) is a scientific experiment on board of the MUSES-A mission of Japan. It is the result of a cooperation between the Institute of Space and Astronautical Science (ISAS) of Japan and the Chair of Astronautics of the Technische Universität München (TUM) of Germany. The MDC is an impact ionization detector designed to deter...

The Munich Dust Counter (MDC) is a scientific experiment on board the MUSES-A mission of Japan measuring cosmic dust. The satellite HITEN of this mission has been launched on January 24th, 1990 from Kago-shima Space Center. Here the present status of the MDC experiment is summarized. The number of dust particles measured so far is presented togethe...

In this work, studies on relationships of chemical compositions between fusion crust and nucleus in iron spherules are reported. More than 10% of the iron spherules which were picked out from deep sea sediment, have cores and crusts. We were able to divide three of them into cores and crusts. Each cores and crusts were analyzed individually by INAA...

Studies on isotopic anomalies in cosmic meteoroids are expected to reveal the features of nuclear synthesis in various phases of star-evolution. The respective isotopes of noble metals had been produced through various reaction processes as well as in various regions of star-eruptions. However, isotopic anomalies of 0s in extremely refractory inclu...

The Munich Dust Counter (MDC) is a scientific experiment on board the MUSES-A mission of Japan measuring cosmic dust. The satellite HITEN of this mission has been launched on January 24th, 1990 from Kagoshima Space Center. Here the present status of the MDC experiment is summarized. The number of dust particles measured so far is presented together...

The Munich Dust Counter (MDC) is a scientific experiment on board of the MUSES-A mission of Japan. It is the result of a cooperation between the Institute of Space and Astronautical Science (ISAS) of Japan and the Chair of Astronautics of the Technische Universität München (TUM) of Germany. The MDC is an impact ionization detector designed to deter...

In order to study large-scaled cosmic matter accretion events in the past, Ir enriched layers at C-T and other geological boundaries and dated sedimental cores have been searched by many scientists. In this work, Iridium contents and the ratios of (Co/Fe) in two dated, respective layers of the cores are determined. These samples were dated fortunat...

The stony spherules collected from deep-sea sediments were analyzed for rare earth elements (REE) by direct-loading mass spectrometric isotope dilution together with examination of their petrographic characteristics. One spherule, which does not show deep sea alteration, exhibits a flat REE pattern with no specific anomaly. Relatively high Ni, Ir,...

A size spectrum of black magnetic spherules which were collected from deep-sea sediments was obtained. Siderophile element (Fe, Co, Ir, and Au) concentrations in 100 spherules, each of them larger than 100 microns, were determined with instrumental neutron activation analysis. About 20% of the spherules showed (Ir/Fe) and (Co/Fe) ratios which canno...

Isotopic compositions of potassium and calcium in individual magnetic spherules were determined. No significant anomaly was observed for potassium within twice the statistical error (2 sigmas), although for calcium isotopes enrichments of Ca-46, Ca-44, and Ca-42 were observed in one spherule. The relative excess of Ca-46, Ca-44, and Ca-42 in the sp...

An extremely low background betagammagamma coincidence spectrometer has been constructed for the measurement of cosmic ray produced radionuclides carried by extraterrestrial matter accreted on the Earth.The detectors used in this work are a large volume Ge(Li) detector, a pair of GM counters of thin layer type for beta counting, a large volume Na...

5 Abstract: Piezoelectric PZT elements were studied by bombarding them with hypervelocity microparticles. The characteristics were discussed with respect to velocity during collision, temperature ranging from room temperature to 150 °C, and incident angles from 0 to 60°. A high temperature state occurred immediately after collision was discussed.

Mars Dust Counter (MDC) is a light-weight dust detector of impact ionization type on board Japanese Mars mission NOZOMI. NOZOMI was launched on July 4th (3rd at UT) 1998. From December 1998 to December 2003 for five years, NOZOMI takes eccentric orbits between the Earth’s and Mars’ orbits. Until April 2002, MDC continuously observed interplanetary...

A PZT element was studied by bombarding silver particles in the mass range from 1 to 100 pg, and the velocity from 2 to 6 km/s. Output signals were uniquely identified on impact. They were processed on Fourier analysis. We found a simple selection rule using a relationship between Fourier components to discriminate junk events. By using the selecti...