EVALUATION OF THE BACK-BOMBARDMENT EFFECT IN THE ITC-RF GUN FOR T-ACTS PROJECT AT TOHOKU UNIVERSITY

Abstract An ITC (independently tunable cells) RF gun is currently used to produce sub-picosecond electron pulses as part of the injector for coherent terahertz radiation at Tohoku University. Experiments and simulations of particle tracing by GPT show that the back-bombardment effect on the LaB6 cathode's surface is serious and should be controlled carefully. To evaluate the temperature increase due to backbombardment a 2D model is created for heat transfer inside the cathode. In the 2D model, the back-streaming electrons are treated as external heat source as well as the cathode heater that heats the cathode from its side along with thermal radiation from its surface. The energy deposit of backbombardment inside the cathode is calculated by EGS5 or Geant4 by use of the information of back-streaming electrons derived from GPT simulation. In addition, we will also compare the simulating results with experimental data on the increase of emission current density of cathode due to back-bombardment

Eph-B4 prevents venous adaptive remodeling in the adult arterial environment

Stimulation of Eph-B4 prevents adaptive remodeling and preserves venous identity when veins are surgically placed into an arterial environment

Driving Behavior during Takeover Request of Autonomous Vehicle: Effect of Driver Postures

We investigated the effect of driver posture on driving control following a takeover request (TOR) from autonomous to manual driving in level 3 autonomous vehicles. When providing a TOR, driving behaviors need to be investigated to develop driver monitoring systems, and it is important to clarify the effect of driver postures. Experiments were conducted using driver postures that are likely to be adopted in autonomous driving. Driver postures were set based on combinations of two types of upper-body posture and three types of foot posture. The driver’s upper body and head were set to either a forward or sideways orientation. For each of these there were three types of foot posture: both feet on the floor, crossed legs, and cross-legged sitting. Following a TOR, we compared the braking and steering maneuvers of subjects driving normally and examined the effects of posture on driver reaction time. The results show that both the upper-body and foot postures of the driver affect the steering and braking reaction time. The driver monitoring system should be able to detect posture and activate a TOR warning, and detection times up to 2 and 1.3 times faster than those for normal postures should be considered for different upper-body and foot postures, respectively

Effect of leucine-to-methionine substitutions on the diffraction quality of histone chaperone SET/TAF-Iβ/INHAT crystals

The combination of leucine-to-methionine substitutions and optimization of cryoconditions improved the resolution of histone chaperone SET/TAF-Iβ/INHAT crystals from around 5.5 to 2.3 Å without changing the crystallization conditions, allowing successful structure determination of SET/TAF-Iβ/INHAT by the multiwavelength anomalous diffraction method

Light source based on a 100 mm-long monolithic undulator magnet with a very short 4 mm-period length

A novel method to fabricate undulator magnets of a-few-millimetre-periodlength is being explored. Plate-type magnets, 100 mm-long with 4 mm-periodlength, have been successfully fabricated. They produce an undulator field ofapproximately 3 kG at a gap of 1.6 mm. Prototype undulators based on thistechnology have been constructed. Field measurements and characterizationshow that the quality of the undulator field of these plate magnets is sufficientfor an undulator light source, and the calculated spectrum shows that thefundamental radiation emitted from this field is quite satisfactory. Testexperiments for light generation using a real electron beam have been carriedout at a test accelerator at the Research Center for Electron Photon Science(ELPH), Tohoku University, Japan, which is able to realize optics conditions toaccept a very short gap of 1.6 mm. First observation and characterization ofblue light was successfully accomplished