摘要:

A technique has been used to measure electron beams in excess of 200 kA/cm2with energies of 105−106eV. The technique uses a high‐level nanosecond risetime Faraday cup combined with a dielectric differential range filter to separate the primary electrons from low‐energy charge carriers in the transport system. This technique has been the one used to measure primary beam currents in excess of 5×105A with pulsewidths on the order of 100 nsec. When combined with a knowledge of particle energy, power flux and deposition profiles may be inferred. A derivation of the electric field generated at the cup collector is included.

ISSN:0034-6748    

DOI:10.1063/1.1685953

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Low energy separated beams into very large bubble chambers, such as the Argonne National Laboratory 12 ft chamber, will have the consequence that many of the secondary particles will be magnetically trapped within the chamber volume. We show that for a highly uniform magnetic field, the turning angle of the tangent to a track of known mass, taken from production to stopping, provides visual estimates of the range to stopping, the total momentum, and the in‐flight decay probability. We also show that these estimates are independent of depth in the chamber and orientation in the magnetic field, and can be obtained for any view projection in the presence of optical distortions.

ISSN:0034-6748    

DOI:10.1063/1.1685954

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Wave number markers are simultaneously traced on the strip chart recording of near infrared spectra by use of an auxiliary optical system employing a Fabry‐Perot etalon. The method is applicable to plane grating scanning spectrometers and is independent of spectrometer source, slit, and detector arrangement.

ISSN:0034-6748    

DOI:10.1063/1.1685955

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

An instrument for the determination of small changes in the rate of decay of a radioisotope has been constructed. It operates on the principle of differential comparison of the unkown decay rate with that of a known, usually practically nondecaying (e.g.,36Cl) reference. The apparatus can be used both for the determination of long half‐lives, and for studying the effect of chemical state upon the half‐life of a radioisotope.

ISSN:0034-6748    

DOI:10.1063/1.1685956

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A convenient method is described for measuring the secondary electron ejection coefficient for thermal metastable atoms striking a metal surface, thereby permitting the absolute determination of metastable atom fluxes. Potential sources of systematic error are discussed. Results are presented for He(21S) and He(23S) metastables striking a gas‐contaminated stainless steel surface.

ISSN:0034-6748    

DOI:10.1063/1.1685957

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The classical four‐pulse experiment of Waugh, Huber, and Ha¨berlen (WAHUHA) is extended to the upper limit in pulse width which is possible in the four‐pulse timing, i.e., the pulse width equals 1/6 of the cycle time. It is shown that coherent averaging is still in effect and high resolution in solids can be achieved to the same extent as in the &dgr; pulse limit.

ISSN:0034-6748    

DOI:10.1063/1.1685958

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A new instrument is described which permits focusing and energy analysis of electrons on any other charged particle coming from a source having a large area. This instrument is specially convenient to measure an electron energy spectrum when a very large sensitivity is required, because the electron optics are such that the entrance slit is no longer required.

ISSN:0034-6748    

DOI:10.1063/1.1685959

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A tunnel diode oscillator is presented which is useful for NMR studies in ferromagnets at VHF and UHF frequencies. The oscillator can be tuned electronically over octave ranges and can be operated at low temperatures. The sensitivity is comparable to standard cw oscillators, but it is much more compact and does not require long rf lines.

ISSN:0034-6748    

DOI:10.1063/1.1685960

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A source for condensible gases and vapors which allows for the production of a pulsed nozzle beam with a beam oven temperature of about 670 K is described. This source is especially suitable for providing the target beam at a beam intersection angle of between 20° and 160° needed for scattering experiments with crossed molecular beams.

ISSN:0034-6748    

DOI:10.1063/1.1685961

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A simple circuit is described for safeguarding superconducting magnets from the large induced voltages which can occur upon quenching or power supply failure.

ISSN:0034-6748    

DOI:10.1063/1.1685962

出版商:AIP    

年代:1973

数据来源: AIP