Hydrogen isotopic replacement and microstructure evolution in zirconium deuteride implanted by 150 keV protons

Zirconium tritiated(ZrTx)is an alternative target material for deuteron-triton(D-T)reaction neutron generator.The isotopic replacement and microstructure evolution induced by hydrogen isotope implantation could significantly affect the performance of the target film.In this work,the zirconium deuteride film deposited on Mo/Si substrate was implanted by 150 keV protons with fluence from 1×10^(16 ) to 1×10^(18 )protons/cm^(2).After implantation,the depth profiles of retained hydrogen(H)and deuterium(D)in these target films were analyzed by elastic recoil detection analysis(ERDA),and time of flight-secondary ion mass spectrometry(ToF-SIMS).Additionally,the microstructure evolution was also observed by x-ray diffraction(XRD)and scanning electron microscope(SEM).The D concentration in the ZrDx film decreased versus the proton implantation fluence.An analytical model was proposed to describe the hydrogen isotopic trapping and exchange as functions of incident protons fluence.Additionally,the XRD analysis revealed that no new phase was formed after proton implantation.Furthermore,circular flakings were observed on the ZrDx surface from SEM images at fluence up to 1×10^(18) protons/cm^(2),and this surface morphology was considered to associate with the hydrogen atoms congregation in Mo/Si boundary.

Terahertz Generation Using Implanted InGaAs Photomixers and Multi-wavelength Quantum Dot Lasers

We report on a study of terahertz(THz) generation using implanted In Ga As photomixers and multi-wavelength quantum dot lasers. We carry out In Ga As materials growth, optical characterization, device design and fabrication, and photomixing experiments. This approach is capable of generating a comb of electromagnetic radiation from microwave to terahertz. For shortening photomixer carrier lifetime, we employ proton implantation into an epitaxial layer of lattice matched In Ga As grown on InP. Under a 1.55 μm multimode In GaAs/In GaAsP quantum dot laser excitation, a frequency comb with a constant frequency spacing of 50 GHz generated on the photomixer is measured, which corresponds to the beats of the laser longitudinal modes. The measurement is performed with a Fourier transform infrared spectrometer. This approach affords a convenient method to achieve a broadband multi-peak coherent THz source.

Deuterium depth distribution study in Yb

The deuterium depth distribution for a 20 keV/D D_3~＋beam implanted into ytterbium（Yb） at a temperature between 300 and 340 K was studied using the D（d,p）T reaction.By analyzing the proton yields,the deuterium depth distribution from the front surface to 500 nm depth was found.The results indicate that an equilibrium deuterium distribution region from the front surface to a depth approximately equal to the mean range of implanted deuterons was formed in Yb during the implantation.The deduced deuterium concentration in the equilibrium deuterium distribution region was D/Yb = 22%.