摘要:

A versatile neutron time‐of‐flight spectrometer suitable for use in the millimicrosecond region is described. Either the rf beam deflection method or the gamma coincidence method is used to provide the zero time indication. Details of these methods, along with spectra obtained for some (d,n) reactions, are given. The two systems are compatible and make use of the same simple time‐to‐pulse‐height converter. The dependence of the decay time of a liquid scintillator on the specific ionization of the detected particle has been used to make the neutron detector insensitive to gamma‐rays.

ISSN:0034-6748    

DOI:10.1063/1.1716441

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

An automatic recording film balance system is described. It consists of a film trough and two pendulum type balances with pressure ranges of 0–400 (800) millidynes/cm and 0–40 (80) dynes/cm, respectively. Each balance is connected to a float when in operation (Langmuir type balance) and the sensing element in both cases is a linear variable differential transformer, the iron core of which is connected to the pendulum. The transformer signal after amplification drives the pen motor of a strip chart recorder. Special features like a constant pressure device together with auxiliary instruments such as a second X‐Y recorder, an automatic dipping device for film transfer, a volta potential meter and a slit viscosimeter permit the automatic recording of the following functions:dFdAT, dAdTF, dFdTA, dFdtT, A, dAdtT, F, AwAsT, F, dVdFT, and d&eegr;dFT.F=film pressure,A=film area,T=temperature,t=time,Aw/As=deposition ratio, &eegr;=film viscosity, andV=volta potential. Test and performance data are presented.

ISSN:0034-6748    

DOI:10.1063/1.1716442

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Detailed descriptive methods are presented for the selection, removal, and preparation for experimental use of both iron and copper whiskers. Techniques which minimize damage are emphasized.

ISSN:0034-6748    

DOI:10.1063/1.1716443

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Vacuum‐tight cryogenic containers can easily be made from Mylar plastic sheet and metal, or from Mylar alone, for use in vacuum‐insulated liquid hydrogen target assemblies. Mylar is bonded very firmly to metals or to itself by an Epon‐Versamid mixture or by Armstrong A‐4. These adhesives maintain strong vacuum‐tight joints throughout the temperature range from 300 to 4°K. Mylar sheet has also proved satisfactory as vacuum‐window material for beam ports. Fabrication of these structures is described in detail, and explosion safety measures are mentioned. Some examples are given of structures which have been used or tested, with data on the ultimate strength of each expressed as the internal pressure required to rupture it. Helium leak testing must be carried out at 77°K or below, because Mylar is relatively impermeable to helium only at low temperatures. The primary electron beams commonly obtained from electron linear accelerators are sufficiently intense to cause Mylar beam windows to fail under vacuum loading, probably because of radiation damage. However, the authors know of no case of radiation damage to Mylar sustained in exposure to secondary beams from high‐energy accelerators.

ISSN:0034-6748    

DOI:10.1063/1.1716444

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

An electron current monitor for linear accelerators has been developed. Its sensing element was a toroidal coil through which the beam passes undisturbed. With appropriate electronic circuity this permitted the true shape of the current pulse to be viewed and also provided an indication of the average beam current on a meter. The average beam current that could be measured ranged from 3×10−8to 3×10−6amp. Furthermore, the use of the current monitor greatly simplified the process of initially obtaining yield from the machine.

ISSN:0034-6748    

DOI:10.1063/1.1716445

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

Two conically tapered single crystals of Al2O3, with small ends abutting, are used to simultaneously effect a high pressure seal and provide a matched transformation from a standard 1‐cm circular wave guide at atmospheric pressure to a circular wave guide terminated by a high‐Q cavity resonator with an internal hydrostatic pressure up to 104bars.

ISSN:0034-6748    

DOI:10.1063/1.1716446

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A time analyzer has been designed which is capable of utilizing the memory of any multichannel analyzer which employs pulse height to time conversion or any similar instrument. The circuit described here has been specifically adapted for use with the Argonne type 256‐channel analyzer. Channel widths from 1 &mgr;sec to >38 &mgr;sec are possible with a minimum dead time of 38 &mgr;sec.

ISSN:0034-6748    

DOI:10.1063/1.1716447

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The extension of optical pumping techniques to solids has been hampered by the lack of suitable light sources. The utilization of photoluminescent effects is proposed as a method for obtaining light sources applicable to optical pumping experiments in some solids, and a ruby source which emits 0.1 w of light at 6934 A and 6920 A is described.

ISSN:0034-6748    

DOI:10.1063/1.1716448

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

An automatic control and programing system for the collection of single crystal diffraction data is described. The system has been designed for a neutron diffractometer, but it could easily be adapted for use with x‐rays.

ISSN:0034-6748    

DOI:10.1063/1.1716449

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A discriminator circuit for use with millimicrosecond counting equipment is described here. The circuit utilizes a diode voltage comparator which drives a secondary‐emission tube univibrator after amplification. Two shaped outputs are provided: one, of short duration, for use with 10‐Mc scalers, and another longer pulse for microsecond scalers.The main characteristics of this unit are its good response to pulses as short as 3 m &mgr;sec and the fast recovery time, which is less than 0.1 &mgr;sec at the fast output.

ISSN:0034-6748    

DOI:10.1063/1.1716403

出版商:AIP    

年代:1959

数据来源: AIP