摘要:

A small, bakeable, magnetically actuated, pulsed gas valve has been constructed which overcomes many of the difficulties experienced with previous designs. Reproducible gas pulses of from 1 to 150 micron liters are readily attainable with the valve described.

ISSN:0034-6748    

DOI:10.1063/1.1719463

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The experimental methods employed at the La Jolla Natural Tritium Laboratory, University of California, for the determination of natural tritium are briefly described. The method is to assay the electrolytically enriched sample as ethane gas in a proportional counter. An error of less than 4% is obtained for samples enriched by reducing the sample volume from 2 liters to 10 ml. It is found that the previous methods of calculating the electrolytic enrichment are not necessary nor are large volume reductions necessary for most applications. In the method adapted at La Jolla the enrichment in five electrolysed samples is determined by using a sixth spiked sample. In this way it is shown that the enrichment in the sixth sample is within 4% of the enrichment in the other five and can be quickly determined.

ISSN:0034-6748    

DOI:10.1063/1.1719464

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

All manual controls of Fox's retarding potential difference (RPD) technique have been replaced by automatic electronic controls applied to a commercial time of flight mass spectrometer. The current difference &Dgr;Ibetween the electron energy voltage increments, is obtained from an electronic data processor and plotted as a function of the ionizing voltage. An ionization efficiency (IE) curve is obtained in 3.8 sec or less. The sensitivity of the system permits an IE curve to be obtained in the 10−8Torr range. An empirical formula was required to correct the present systematic error. The error was found to be −3.67+0.834x−0.0306x2for xenon, krypton, and argon, wherexis the ionizing voltage of the data. This formula was used to correct the experimental water ionization potential (IP) to give 12.59±0.05 V. The spectroscopic water IP is 12.61 V.

ISSN:0034-6748    

DOI:10.1063/1.1719465

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

The design of the iris‐loaded deflector for the Panofsky type rf beam separator now under construction at the Brookhaven AGS is presented. General expressions for the transverse momentum acquired by an ultrarelativistic particle traversing the deflector are derived from the field equations. Useful figures of merit (shunt impedanceR, series impedanceZ, quality factorQ, R/Q, etc.) are defined. Computational results for the aperture radiusa, the guide radiusb, Q, R/Q, andRas functions of group velocityvg, the number of irises per wavelengthN, and iris thicknessd/ware presented for structures with the phase velocityvp=c. They are compared with experimental results reported from deflection tests. The design procedure of a deflector is developed for the realistic case that the shunt impedance varies with group velocity. Optimization of operating frequencyf&pgr;/2, deflector lengthl, vg, d/w, andNis carried out. Higher order modes in iris‐loaded waveguides are investigated and methods for the suppression of mode degeneracies are outlined. The effect of the mechanical tolerances on the phase shift per cell &PHgr; is considered. The chosen deflector structure has &lgr;0=10.495 cm,N=4, &PHgr;=½&pgr;,d/w=0.8, 2a=48.13 mm, 2b=116.71 mm,l=3.07 m, rounded iris edges, and lateral rods as mode stabilizers. ``Cold'' measurements on cavities and waveguides are described, and a preciseR/Qperturbation method is detailed. Pertinent results aref&pgr;/2=2856.35 Mc,Q=8700, phase error per cell &Dgr;&PHgr;=2.7° rms,R/Q=1.41 k&OHgr;/m,vg/c=−0.0204, &agr;l≈0.5. It is concluded that a klystron pulse of ≥14 MW is sufficient to give a 1 mrad peak deflection of 18 GeV/cparticles.

ISSN:0034-6748    

DOI:10.1063/1.1719466

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Quantitative Coulometric analyses for water yield are made during thermal dehydration of rock materials and other solids. An electrolytic hygrometer cell is utilized to quantitatively measure the evolved water from a solid at known temperature as it is uniformly heated to a maximum of 1200°C. By reduction of total exposed adsorbing surface area in the retort and in the electrolytic cell coupling system, the lag between the dehydration event in the sample and cell response has been reduced to a very few seconds, thus permitting direct correlation between sample temperature and hygrometer cell current. The rapid cell response permits the resolution of discrete dehydration events and defines the temperature range through which they occur. Specific temperature‐desorption data gained with this instrument have been very helpful in gaining an understanding of the modes of constitution of water in silicates.

ISSN:0034-6748    

DOI:10.1063/1.1719467

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Bridgman anvils have been adapted for Hall effect measurements, thus extending the pressure range of such measurements considerably. Multiple probes are introduced into the high pressure cavity by using an epoxide adhesive. Magnetic fields are produced axially: the anvils are used as pole faces. Samples are embedded in silver chloride to decrease nonhydrostatic effects. The technique is demonstrated by measurements performed with bismuth and tellurium. Problems of calibration are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1719468

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A correlator‐amplifier system based on a Hall multiplier improves the sensitivity of low level amplifiers by two to three orders of magnitude. The system is assembled largely from commercial instruments, with the exception of the Hall element itself. Over the frequency interval from 10 cps to 10 kc, the equivalent input noise level ranges from 5×10−15to 10−19V2/cycle. The system is capable of detecting correlated signals presented to both inputs in the presence of uncorrelated noise two to three orders of magnitude greater.

ISSN:0034-6748    

DOI:10.1063/1.1719469

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

An air‐cored betatron has been constructed whose coil is effectively a single turn made up from four circular turns connected in parallel. The design was facilitated by choosing independently the positions of the four parallel turns and the current distribution through them. The desired current distribution was obtained by making two of the turns in the form of toroidal coils whose inductance could be adjusted. The betatron has been used in combination with an azimuthal magnetic field for the production of an intense stream of runaway electrons, consisting of essentially all the electrons of a plasma. After a short interval (∼0.1 &mgr;sec) of normal acceleration, the electrons experience less‐than‐normal acceleration followed by deceleration and disruption of the stream. Intense bursts of microwave radiation occur during the current pulse. The observed stream behavior is reasonably well explained by the theory of the two stream instability.

ISSN:0034-6748    

DOI:10.1063/1.1719470

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

An elutriation particle separator is described which provides an inexpensive, efficient, and accurate method of obtaining from an original mixed sample sizable fractions of particles with diameters within preselected size ranges. Preliminary results for three size ranges between 10 and 100 &mgr; are presented, together with proposed modifications (including a connected series of separators) for more efficient operation.

ISSN:0034-6748    

DOI:10.1063/1.1719471

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A major microcalorimetric problem, the development of a very sensitive thermometer, is considered. The theory of a pyroelectric thermometer is reviewed and verified calorimetrically. A thermostatic system utilizing both a layer of low thermal diffusivity material and a large heat sink was used to strongly attenuate external temperature fluctuations. A pyroelectric thermometer, used in the thermostat, measured temperature changes as large as 2.52×10−3°C and as small as 6×10−6°C. The sensitivity of the thermometer was limited by the temperature stability of the thermostat. Technically simple modifications of the calorimeter could make the detection of temperature changes as small as 5×10−7°C possible. Detection of temperature changes smaller than 10−7°C may be achieved by changes in size, shape, and material of the pyroelectric sensing element.

ISSN:0034-6748    

DOI:10.1063/1.1719472

出版商:AIP    

年代:1965

数据来源: AIP