摘要:

A simple circuit is described which closes a shutter on the optical input of a photon counting detector when the photon count rate exceeds a preset level. The circuit utilizes common integrated circuits, and is designed to protect microchannel plate photomultipliers from excess light exposure.

ISSN:0034-6748    

DOI:10.1063/1.1144794

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

A simple digital correlator with four independent inputs is described. It gives 20 correlation points for each channel, with a maximum sampling frequency of 1 MHz, and is fully computer controlled. The correlator is designed to match the requirements of dynamic light scattering detectors in liquid chromatography.

ISSN:0034-6748    

DOI:10.1063/1.1144795

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We present a novel pulsed valve design that is especially suited for use with severely corrosive gases. The design is unique in that the stem seals the gas inlet, rather than the outlet. All parts in contact with the high‐pressure gas flow are constructed of ceramic and fluoroplastics.

ISSN:0034-6748    

DOI:10.1063/1.1144796

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Temperatures of a birefringent substrate (LiNbO3) have been measured by laser interferometry in a 13.56 MHz rf discharge. The measurement method is based on monitoring the variation of natural birefringence with temperature. The transient temperature rises and equilibrium values are investigated in nitrogen plasma at rf powers of ∼86 W. Owing to the large heat capacity per unit area of the substrate, the time constant of temperature rises is about ten times as large as the previously reported value of a polymer substrate (PMMA).

ISSN:0034-6748    

DOI:10.1063/1.1144739

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

We describe a prototype electrocardiographic (ECG) array system comprising 25 ultrahigh impedance sensors, which does not require ohmic electrical contact with the body.  

ISSN:0034-6748    

DOI:10.1063/1.1144740

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Streaked shadowgraphy based on a simple coaxial flashlamp‐pumped dye laser as the probing light source is applied to a plasma focus pinch in argon fill gas. This resolves a major problem in using the normal streak photography for capturing the gross dynamics of argon focus pinch, in which its plasma luminosity as a function of time is highly nonuniform.

ISSN:0034-6748    

DOI:10.1063/1.1145229

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

dc micromotors have been used to rotate helium 4 crystals in a pressurized cell (25 bars) at very low temperature (down to 30 mK). After slight modifications of the motors and optimization of bearings and transmission design, rotations of ±6° were obtained with an accuracy of ±0.01° and a dissipation of 20 &mgr;W.  

ISSN:0034-6748    

DOI:10.1063/1.1144741

出版商:AIP    

年代:1994

数据来源: AIP