摘要:

An interferometer using coaxial CO2and He–Ne lasers has been developed for electron density measurements in the reversed field pinch plasma. The interferometer uses the phase modulating heterodyne detection of 60 MHz. The CO2laser interferometer is free from the mechanical vibrations due to the reduction of the vibrations by the air springs and the compensation of the vibrations by the He–Ne laser interferometer. The electron density measurement during a long‐time discharge of 50 ms without the disturbance by the vibrations is achievable. The resolution is less than 1/100 fringe of the CO2laser interferometer, therefore the electron line density as small as 1.1×1014electrons/cm2is detectable.

ISSN:0034-6748    

DOI:10.1063/1.1138644

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A hydrogen cyanide laser interferometer with three vertical chords was installed in the JFT‐2M tokamak for electron density measurement. The optical arrangment of the interferometer is a Mach–Zehnder type and its structure is mechanically independent of the JFT‐2M machine in order to suppress the mechanical vibration. Two HCN lasers are employed for direct reading of the chord averaged electron density by means of beat modulation method. The beat frequency between two HCN lasers is stabilized at a constant frequency by a feedback circuit using a microcomputer. A combination of short dielectric waveguides and TPX lenses is employed to compensate the refraction and divergence of the laser beam. It was shown experimentally that the interferometric measurement of the electron density was scarcely affected by the mechanical vibration of the interferometer and the refraction of the probing laser beam up ton¯e=6×1019m−3.

ISSN:0034-6748    

DOI:10.1063/1.1138590

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We present measurements of multilayer mirror reflectivity and stimulated emission in the XUV spectral region. A molybdenum–silicon multilayer mirror with 12% measured reflectivity at 182 A˚ was found to produce a 120% enhancement of the C vi182‐A˚ line (3→2 transition) in a strongly recombining plasma. No such enhancement of the C v186.7‐A˚ line was seen, demonstrating amplification of stimulated emission at 182 A˚.

ISSN:0034-6748    

DOI:10.1063/1.1138591

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The design and performance of semiconductively preionized nitrogen lasers employing optimized capacitor transfer excitation circuitry are described. These lasers of minimum complexity are capable of producing ultraviolet pulses of up to 1 mJ and 150 kW at efficiencies of more than 0.04%.

ISSN:0034-6748    

DOI:10.1063/1.1138592

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A novel optical and mechanical arrangement for a tunable distributed feedback dye laser is described. The spectral bandwidth and the pulse duration of the laser emission are almost transform limited in a tunable spectral range from the near UV to the near IR.

ISSN:0034-6748    

DOI:10.1063/1.1138593

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new microprocessor‐controlled multichannel spectrometer for the measurement of fluorescence detected circular dichroism (FDCD) is presented. Spectra of model steroid compounds are provided to demonstrate the analytical utility of multichannel FDCD over the classical circular dichroism measurement. A detection limit of 3.05×10−8M was determined for a solution of estrone based on a signal/noise ratio of 2 as a lower limit. The optics and electronics for the rapid acquisition of multichannel FDCD data are described in detail.

ISSN:0034-6748    

DOI:10.1063/1.1138594

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new, compact (approximately fist sized), efficient electron‐spin analyzer is described. It is based on low‐energy (150 eV) diffuse scattering from a high‐Ztarget, for example, an evaporated polycrystalline Au film opaque to the incident electron beam. By collecting a large solid angle of scattered electrons, a figure of meritS2I/I0=10−4is achieved with an analyzing powerS=0.11. The figure of merit degrades only marginally (<10%) for beams with an energy width of 40 eV or after one month of operation at 10−8Torr. The electron optical acceptance is of order 100 mm2 sr eV. The details of the design and construction are discussed and its performance is compared to six other spin analyzers. Illustrative results are presented from an application to scanning electron microscopy with polarization analysis (SEMPA) to image magnetic microstructure.

ISSN:0034-6748    

DOI:10.1063/1.1138595

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We describe a normal incidence grating spectrometer for use in inverse photoemission studies of surfaces. We show that by operating in a configuration where the source and image are displaced from the Rowland Circle it is possible to construct a useful spectrometer that can be attached to any existing surface science chamber. The device covers the range 10–30 eV in photon energy with a typical energy resolution of 150 meV. Capable of operating with relatively low incident currents, this instrument will be an excellent choice for spin‐polarized inverse photoemission experiments.

ISSN:0034-6748    

DOI:10.1063/1.1138596

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

An electric‐field cross‐correlation technique is described which can be used for measuring microwave rotational absorption spectra and which has a wide range of applications in other areas. The spectrometer is a novel implementation of a Michelson interferometer. The wide bandwidth source is obtained by modulating a single‐frequency signal with a pseudorandom binary sequence. The variable phase delay for determining the cross‐correlation function is obtained synthetically from an identical but out‐of‐phase pseudorandom sequence. The spectrometer operates at X‐band frequencies with a bandwidth of &bartil;100 MHz and a resolution of &bartil;100 kHz. TheJ=1←0 transition of16O12C32S was observed.

ISSN:0034-6748    

DOI:10.1063/1.1138597

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A high‐performance frequency‐swept capacitance bridge detector for ion cyclotron resonance (ICR) spectrometry has been constructed in our laboratory. Although the basic design of the system is similar to that of previously reported bridge circuits, careful design, layout, construction, and component selection have resulted in excellent frequency‐swept performance over a bandwidth of 15 kHz to 1 MHz. At a magnetic field strength of 1.0 T, this corresponds to a mass range of 15–1000 Daltons. Problems with base‐line drift and frequency‐dependent signal distortion common to many other designs have been significantly reduced. Circuit diagrams are included for all parts of the detector and frequency response curves have been included where appropriate. In addition, several simple circuit diagrams for support devices have also been included.

ISSN:0034-6748    

DOI:10.1063/1.1138598

出版商:AIP    

年代:1986

数据来源: AIP