摘要:

We have developed a new type of microwave ion source which has an axial magnetic field generated by a permanent magnet. By the combination of the permanent magnet and ferromagnetic materials, a closed magnetic circuit is formed through an ion extraction electrode. This axial magnetic field is utilized both for the high‐density plasma production by the electron‐ cyclotron resonance process and for the high efficient ion extraction by transporting the generated ions along the magnetic force lines. The continuous ion beams of 2–3 mA are delivered from the extraction aperture (2 mm in diameter) when various gases (Ar, N2, CO2), metal vapors (Cs, Rb), and reactive gas (O2) are used. Extremely low impurities are present in the extracted ion beam. An ion beam with low emittance of 10−8m rad order and high brightness of 1011A m−2 rad−2order is obtained. The size of this ion source is 50 mm in diameter and 65 mm in height. The discharge power of the microwave with the frequency of 2.45 GHz is 7 to 30 W. Thus, a high‐current microwave ion source with compact structure and low power consumption is realized.

ISSN:0034-6748    

DOI:10.1063/1.1137795

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The application of 180° Thomson scattering using ultrashort laser pulses for measuring electron temperature and density profiles in large fusion devices is proposed. Spatial resolution along the laser beam is achieved by high‐speed detection allowing time‐of‐flight measurements. This LIDAR (light detection and ranging) technique uses a minimum number of window ports and reduces the number of optical components in the vicinity of the discharge vessel. As an example, the performance of such a system for the JET tokamak geometry is discussed on the basis of available laser and detection technology.

ISSN:0034-6748    

DOI:10.1063/1.1137796

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Certain materials useful in space sensor construction were tested for their noncontaminating compatibility with channel electron multipliers. Gain profiles indicate that the materials tested do not adversely affect the lifetimes of the multipliers. These materials are, therefore, shown to be safe for use with channel electron multipliers in space instrumentation even for the most stringent long lifetime mission requirements. The tests indicate that the multipliers which are to be flown on an extended space mission will have adequate lifetimes to return satisfactory data throughout the entire mission.

ISSN:0034-6748    

DOI:10.1063/1.1137797

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The momentum reflection of accelerated H2cluster ions in the energy range of 1 to 10 eV per atom on various surfaces differing by their roughness has shown to vary by more than 61%. By use of the surfaces having a higher absorptive power, the momentum of such particle beams can be measured more accurately.

ISSN:0034-6748    

DOI:10.1063/1.1137798

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Measurements of electron‐beam (e‐beam) energy deposition in gaseous medium by a segmented totally stopping calorimeter and a pressure jump method are described, both of which gave the same values. Typicale‐beam parameters are 2 MV, 80 kA, and 65 ns (FWHM). Thee‐beam cross‐sectional area is 10 cm in diameter. First, the radial distribution of thee‐beam current generated from the field‐emission diode as a function of the axial magnetic field was measured. Next, for applications to longitudinal excitation of the high‐power gas lasers, thee‐beam energy deposition characteristics are measured in N2for the propagation distance up to 2.3 m in terms of the axial magnetic field, the N2gas pressure, and the radiale‐beam distribution. As a result, the axial field equivalent to the self‐magnetic field of the electron beam can acceptably control thee‐beam generation and propagation uniformities.

ISSN:0034-6748    

DOI:10.1063/1.1137799

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The article presents the results of experimental investigation on an atmospheric‐pressure N2oscillator low‐pressure N2amplifier system. This system gives pulses of a duration of about 0.8 ns, with 800‐kW peak power, and good (±3%) stability. The parameters affecting the oscillator–amplifier operation are discussed with the aim of optimizing system performances.

ISSN:0034-6748    

DOI:10.1063/1.1137800

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A completely passive closed‐cycle flowing alkyl‐iodide (C3F7I) gaseous supply system which provides a high purity and fixed pressure of gaseous C3F7I at a well‐regulated flow velocity is reported. Its employment produces an extreme cost saving and the generated flowing gas can easily be coupled with cw atomic iodine photolysis lasers to produce excellent results. The low‐temperature evaporation/condensation baths (<0 °C) freeze out all of the excited atomic iodine quenchers H2O and I2present in liquid C3F7I.

ISSN:0034-6748    

DOI:10.1063/1.1137776

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The construction and operation of a cross‐correlation phase and modulation fluorometer using the synchrotron radiation facility at the ADONE–Frascati electron storage ring is described. In the frequency domain the high repetition rate pulsed source gives a large series of equally spaced harmonic frequencies. Use of cross‐correlation techniques in conjunction with such a light source permits one to isolate one harmonic frequency from the adjacent frequencies with high precision. The cross‐correlation frequency required for the analysis of the phase delay and modulation ratio is obtained using two coupled frequency synthesizers, one of which drives the radio‐frequency cavity of the storage ring and the other which modulates the response of the photomultipliers used for the signal detection. The accuracy, reproducibility, and sensitivity of the instrumentation have been determined on a number of systems and are reported.

ISSN:0034-6748    

DOI:10.1063/1.1137777

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

An electronic system is described that subtracts the analyzing light signal level from the analyzing light signal modulated by a transient absorption signal at the output of a photodetector in a transient absorption spectrophotometer. The system enables sensitive measurement of the transient with simultaneous measurement of the analyzing light level immediately before the transient. The shortest rise time is 50 ns. The time window for the measurement can be selected to a maximum of 20 ms with a droop of 20 &mgr;V. Input signals of 10 V of either polarity are permitted. The minimum detectable absorption signal is determined by the noise of the photomultiplier used and can be about 0.2% for an experiment without signal averaging.

ISSN:0034-6748    

DOI:10.1063/1.1137778

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A low‐cost double beam spectrophotometer using separate detectors is described. This device, capable of transmission measurements as low as 0.001%, incorporates computer response correction for both beam differences and fluctuations in detector power supply and light source. This type of measurement is achieved without the use of high‐quality optical components or hardware‐based response correction.

ISSN:0034-6748    

DOI:10.1063/1.1137779

出版商:AIP    

年代:1984

数据来源: AIP