1982 Vol. 6, No. 5
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A precise attenuation length λ is greatly important in calculation of shielding, sincethis parameter influences the radiation field transmitted by an accelerator shield. Thecost may be considerablely reduced, if the reasenable paramaters are accepted. Nuclude spectral analysis of concrete samples taken from the shielding wall near bythe target of high energy accelerator have been made. The attenuation length λ isdetermined and compared with results from other labordtories.
The prototype of the time expansion chamber, one kind of drift chambers, inwhich the drift region and amplification region is well separated, is described. Its prin-ciple, characteristic, construction and some experimental results are given in detail, Theseresulte are: signals of ionization process along a single charged particle track; the driftvelocities of the electrons in several gases; and the counts distribution of the ionizationclusters in the unit track of a beta particle. And some possible improvements of theseexperiments and the possible applications of this chamber are discussed.
We have measured multiplication factor of a Multistep Avalanche Chamber filledwith Argon-Triethylamine mixture gas, then compared it to the results reported inreference The detection efficiency of this chamber has reached 98% by measuringelectrons emitted from 90Sr β source. The plateau is more than 200 volts.
The Coupled resonator model and the distribution of the electric Field on the axisin the singly periodic cavity chain and biperiodic chain with full-cavity terminationsare analysed by Helmholtz Equation using the symmetry properties of the structure.It is another method to check coupled circuit theory. The results given in this paper forthe singly periodic cavity chain with full- cavity terminations was verified by a 600MHZ linac model of IHEP.
If we give appropiate constraint to the gauge invariant Lagrangian, the variationprinciple of the action convert to the variational problems with subsidiary condition.The effective Lagrangian which contains Lagrangian multiplier may has the mass termof the mesons. In that case we obtain naturally the massive Yang-Mills fields which wasdiscussed by Nakanishi.
Using the hypothesis of the bag-quarks' wave-function with the property of transla-tion invariance, and introducing a Lorentz-invariant effective Lagrangian, we have cal-culated the nucleon deep -inelastic structure functions In our calculation the4-momentum conservation is satisfied automatically, while the resultant structurefunctions are positive-definite and vanish when x>1. Furthermore, using the assumptionof the asymptotic freedom, we obtain explicitly the Bjorken scaling, the approximateexpession F1 (x～1)∝(1--x)4, and by the way, a new counting rule Computercalculation gives the F2(x) curve which seems to be consistent with the data in therange of 0.4<x<1.
In this paper, the various longitudinal transport characteristics of the beam bunchare described. For example, the bunching of the spread bunch, the forming of thelongitudinal image and waist, the longitudinal wais to waist transfer, the longitu-dinal π-transition and the modulation of momentum spread, etc., are systematicllydiscussed. The corresponding universal calculaion formula are also presented.
Using nonrelativistic Eikonal approximation, we derive exactly the scattering am-plitude of two complex systems with different masses. The center of mass correctionfaetor is given too.
There are 24 elemente of four-particle symmetry group S4. By use of SubstitutionalAnalysis can obtain the unitary representation of this group. Then, have the orthogonalunits.
In the framework of the eikonal form of DWIA and using the transition densitymethod, the differential cross sections for 13O (π,π') .18O* (2+, 1.98 MeV) inelasticscattering at Tπ=230 MeV are calculated. The ratios of the integrated cross sectionsfor π- vs. π+ bombardments, are analyzed and the effects of changing the neutron radiusto the differential cross sections are studied as well. Our results fit the data quite well.
In this paper, rotation of the system consiting of N—1 (sd) bosons and one (pf)boson is discussed on the assumption that the SU(3) limit is just the rotational limit.Using group-theoretical methods, we have given rotational spectra of negative parity,and have derived the analytic expressions of the reduced matrix elements of the E3transition from the v0-band (Kπ=0-) to the ground band. In terms of the inegualityof the intensities of (sd)-(sd). interaction and (sd)-(pf) interaction, the differencebetween the parmeters of positive-parity bands and those of negative-parity bands areexplained qualitatively.
In this paper, we present energy spectra and angular distributions for the α-par-ticles emitted in the reaction of 12C+197Au at 64 and 67 MeV and for α, Be and B emittedin the reaction at 71.5 MeV. The most-probable energles of the variousproducts emittedin this reaction decrease.with decreasing incident energy. The angular distributions peak near grazing angle.The peak position of the angular distributions shift from--80°to--120°while the projec-tile energy decreases from 71.5 MeV to 64 MeV. These all show the features of the transferreaction. The 6Li product also has been measured and the 8Be particle emitted from thisreaction was detected at 90°to the beam direction using α-α coincident technique at 71.5MeV. The coross section of the 3Be is only few percent at the same angle.
In this paper the calculation of the microscopic optical potential based on thegeneralized Skyrme forces which describe both the ground and excited state propertiessimultaneously has been carried out for 205Pb ete. The volume integral per nucleon andthe root mean square radii of the real part as well as the imaginary part of the opticalpotential have been obtained. The angular distributions of the elastic scattering andthe total cross sections by use of our computed microscopic optical potential for 20?Pbhave also been calculated. Compared with the conventional Skyrme forces, the calculat-ed results by the generalized Skyrme forces are evidently improved The presentcalculation is also in a good agreement with experiments for the incident energy lessthan 100 MeV.
The group chain U5O5SU2×SU2 used by K. T. Hecht (1965) and by the othersprovides an important representation for expressing the physical basis of d-boson sys-tems. However the methods which have been introduced for this SU2×SU2 representa-tion to construct a physical basis is poorer in comparison with those for the otherrepresentations. In view of this we try to find appropriate methods to obtain the SU2×SU2 representation wave functions of the existing physical bases constructed byChacon et al. and by Szpikowski et al., In the present paper we analyse the SU2×SU2 tensor properties of the,bosonoperators and Vilenkin's traceless boson operators and express succinctly the elementaryvectors of the SU2×SU2 basis, the |PP SU2×SU2 > vectors, in terms of the tracelessoperators. With the help of this form of the| PP SU2 SU2> vectors we derive a simpleformula for obtaining the SU2×SU2 -representation wave functions of a physical basisfrom its (nμ)-representation wave functions. Thus the problem mentioned above is partlysolved. The other parts of the solution of the problem will be found in a coming paper.
The present paper examines theoretically the way of reducing tha errors introducedby the inaccuracy of the decay constant and measuring statistics in the determinationof the number of the radioactive atoms. It was discovered that the "front-back sym-metrical measurements with life-time as center" (FBSLC) may fulfil this reguirement.Even if the error of the decay constant reaches ±10%, the error introdnced by theinaccuracy of decay constant of the number of the radioactive atoms at zero time cal-culated from the radioactivities measured at zero time and two life-times by takingaverage will still be smaller than 0.1%. Experimental data of 99mTc radioactive decaywithin measuring statistics verified the above theoretical prediction. Therefore, by FBSLC with measuring time as early as possible, it is possible toreduce the errors introduced by inaccuracy of the decay constant and measuring sta-tistics, so that the results of the absolute measurements may be more accurate.
The importance of Coulomb effect for π-12C, 16O scatterings is studied at incidentenergy Tπ=80, 70, 50, MeV. Results show that the discrepancy between the data andthe calculation that appears in differential cross section for Tπ=50 MeV in referenceis not attributed to ignoring Coulomb effect. The Coulomb effect in such energy regionis negligible, except small angle region in the differential cross sections at. Tπ=50 MeV.
It is pointed out that a quark-diquark model might improve the fit to baryonicmagnetic moments with a minimum of parameters. A calculation by using this modelgives good agreement with the magnetic moment of ∑+ and E0.
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