摘要:

Clean Viton and Viton coated with Apiezon‐L vacuum grease were tested for their noncontaminating compatibility with channel electron multipliers (CEMs). The test setup and procedure were the same as those used previously in conjunction with CEM compatibility tests of certain epoxies, solder, and fluorocarbon polymer materials useful for construction of spaceflight sensors. While some CEM gain degradation was noted during exposure to Viton and Apiezon‐L, the present tests indicate that, at least over instrument lifetimes of ∼2×1012counts, these materials should be suitable for (1) preflight space sensor testing systems, (2) hermetic seals for CEM‐based space sensors, and (3) terrestrial CEM‐based instrumentation.

ISSN:0034-6748    

DOI:10.1063/1.1139346

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have designed a low‐loss dielectric sample holder for positioning very thin, metallic, semiconductor samples in a TE102cavity for ESR studies at liquid‐helium temperatures. The sample holder can be rotated ±15° from the center position, allowing accurate positioning of the high‐conductivity sample at minimum electric field. This results in maximizing theQfactor and allowing symmetric excitation on both faces of the sample. We have also devised a method of setting the microwave phase to desired value to better than 0.3° by utilizing the hyperfine lines of a dilute As‐doped Si sample.

ISSN:0034-6748    

DOI:10.1063/1.1139347

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have developed an active voltage source with low‐noise characteristics. The circuit was designed to drive components at constant voltage which are sensitive to extrinsic noise and power‐supply zero‐crossing transients.

ISSN:0034-6748    

DOI:10.1063/1.1139348

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A simplified version of a deuterium pellet gun based on the pipe gun principle is described. The pipe gun is made from a continuous tube of stainless steel and gas is fed in from the muzzle end only. It is indicated that the pellet length is determined by the temperature gradient along the barrel right outside the freezing cell. Velocities of around 1000 m/s with a scatter of ±2% are obtained with a propellant gas pressure of 40 bar.

ISSN:0034-6748    

DOI:10.1063/1.1139349

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A venetian style infrared attenuator placed prior to a pinhole spatial filter results in variable high‐power laser attenuation. This attenuation scheme has a wide dynamic range, results in high‐quality Gaussian beams, does not introduce beam walk‐off error, and is independent of polarization.

ISSN:0034-6748    

DOI:10.1063/1.1139651

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The shutter ratio of a proximity focused ITT F4128 microchannel‐plate (MCP) photomultiplier is investigated for gated photocathode‐to‐MCP gap voltages. At counter potentials of greater than 3 V, the shutter ratio is better than 1013for incident light with a wavelength longer than 600 nm.

ISSN:0034-6748    

DOI:10.1063/1.1139298

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The easy‐made automation of the liquid4He transfer is reported. This automation needs little modification of the present system. We only added the liquid4He levelmeter and two electromagnetic valves to the conventional liquid4He transfer equipment. The automation saves much time in charging liquid4He. The performance is satisfactory.

ISSN:0034-6748    

DOI:10.1063/1.1139299

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A probe light source with uniform spectral output is required to obtain constant signal‐to‐noise ratio in absorption spectra taken with an optical multichannel analyzer. Suitable filters to balance the spectrum of the flash‐lamp source discussed here are unavailable. Instead a device is proposed which equalizes the spectrum of the probe source after it has been dispersed by the spectrograph of the optical multichannel analyzer.

ISSN:0034-6748    

DOI:10.1063/1.1139300

出版商:AIP    

年代:1987

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1139669

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

An easily programmable stepping motor control is based on an IBM‐PC compatible parallel printer interface.

ISSN:0034-6748    

DOI:10.1063/1.1139301

出版商:AIP    

年代:1987

数据来源: AIP