The construction of the cloud chamber was carried out with the help of skilled draftsmen and machinists from the California Inatitute ehop faculties. Such movement was achieved by means of a compression chamber at the rear of the piston. Control of the eUectile chamber by an expansion mechanism at the back of the compression chamber.
A small leak was maintained in the press chamber as a further guarantee for the actuation of this safety mechanism. The main power supply at the bottom of the rack has 300 volts regulated to the various.
CHASSIS "I AIR CO NDITIONER J
OPTICAL SYST . EM
Arcins of the tubes, tbus discharge of the condenser banks, was effected by means of an induction, or tickler, eoU which in turn it received a pulse from \.be control chassis. The visual system consisted of eight (8) film projection globes, dirty (4) on each side of the room. Tbia aecond ayetem was necessitated by the inability to look at the high intensity flash of the first system.
Visual inapection was required to set the room expansion ratio. A drive motor rotated any number of U.ghts through 180 degrees into the focus of the paraboloid at the correct circuit.
TARGETS
- THEORY O F HIGH ENERGY INTERACTIONS
W* • total energy of the incident nucleon in the center of mass system. rest mass energy of the produced mesons. 8 • angle measured in the laboratory system from a line along which the relative velocity of the laboratory and the center of maee systems occurs. Q • • angle measured at the center of mass from a line along which the relative velocity of the laboratory.
A • atonic strength of the absorber Z • atomic number of the absorber r 8 • classical radius of the electron. A graphical solution of the approximation B of the general caacade theory is alven in Ro5st8).
PHOTOMETRIC UESULTS
As pointed out above, the white lsvel was not equally intense on both sides of the photon-electron cascade peaks. Additional care had to be taken to ensure that all traces were of the same ionization. The problem of the penetration of the tracks of strongly ionizing nucleons and pions was never completely solved.
Only rough estimates could therefore be made of the polluting contribution of the heavy tracks. Because these cascades had approximately the same energy, applying the equal-energy gamma-ray formula in Appendix D yielded an energy of 1. Both photometric and visual counts at the maxima of the two cascades yielded 40 particles, which corresponded to an energy of 1.46 Conf.
The n:odulation of this linear proportionality between the number of particles at the maximum, Nmax* and the energy of the shower, EO, by the factor (ln Ec/Ec)-1/Z given by the general cascade theory was ignored. Even beyond the modulation factor given above, uncertainty was introduced by the technique due to the powerful distribution of the aamma rays. The triggering of the cloud chamber was investigated as a function of the (A) Interaction Location and the (D) Primary Particle Energy.
At frame 99.151, a change was made to the display of the bodoecope, which was described in Chapter II. The two top rows of eight (S}hodoscope Uabta were connected in parallel with the top of the two Geiger counter trays.The lights shown from right to left corresponded to the Geiger counters fired front to back in a tray as seen from the vantage point of the camerns.
INTERACTION LOCATION
- DOUBLE NUCLEAR INTERACTION ANALYSIS
The bottom two rows of eight (8) hodoscope lights were connected in parallel to the bottom tray of the geiger counter. The purpose of the parallel connection was to provide a redundancy in the visual display since random failure had occurred in the hodoscope due to the critical matching of tubes and neon lamps in different channels. In those cases, the highest number of Ughta illurr obtained is taken as the number of geiger counters fired.
The number of nuclear interactions above 50 Bev for each of the four (4) parh waa plotted against n11 total number of geiger counters fired. Data were also normalized to an equal number of cases in each of the four parts (not illustrated). Inspection of the f'lgura 13 reveab no apparent blas in trlgaerlng for the location of the events at the end of the cham•.
The fifteen (15) cases in the third quarter flrlng sl:teen (16) counters do not appear to be statistically significant. For this purpose, the median angle formula was used to estimate the primary particle energy. As can be seen, and would be expected, the higher energy events activated more counters.
It's hard to explain this exception to the general rule except in ter.rr.
SELECTION CRITERIA
A typical double nuclear interaction is shown in Figure 17, page 56. 1) The projected line of flight of the incident particle that caused nuclear interaction had to pass through both the top and bottom steel plates in the chamber within a radius of 58 inches at ZZ inches surface of the plate. The second factor, that of the nuclear nature of the event, was determined in part by the elimination of events that occurred on the flat plate. Photon-electron cascades resulting from gamma rays produced above the chamber were eliminated as, as calculated in Section IV, there was 1. Elimination of events in plate one also allowed observation of the incident particle trail through two chambers of 10 cm possible for easier determination of the first criterion.
This criterion formed the bottom of the first plate and the top reference reference. In the presence of penetrating particles, this number of plates was not necessary, as the penetrating particles dissipated some of the energy. In addition, by observing the cone angle of the mesons and nucleons emerging from the interaction, one could determine the energy by using the median angle formula discussed in Section III.
If a double interaction occurred in which the large interaction met the above criteria and the small interaction did not, aa was the case for the two events in which the small interaction occurred in the first panel, the. treated the interaction as a single interaction. Many large interactions that satisfy criteria 1 to 3 above and where a small interaction occurs according to criterion 4 cannot be considered double nuclear interactions because the smaller interaction was not nuclear. The nuclear nature of the small interaction was established using the above Zb criterion.
The selection criterion that establishes the upper energy limit for the enamel interaction will be discussed in a later section. Appendix E describes the method used to obtain au approximate £ornJula for the true angle in space • QT • The derived relation was. The number of plates f1:om the upper reference reference to the point of the major interaction, including the fraction of the plate, was tabulated.
Sec 8 GRAPH
- S E LECTION CRITERIA
- CROSS-SECTION FOR INTERACTIONS OF ENERGY GREATER THAN 50 BEY
Two (2) caae were controversial due to the wide angle dispersion of the penetrant particles generated. An analysis was performed to determine the ratio of the total energy to the energy of the rest mass at the center o. Pc - center speed o. as seen in the laboratory system ) divided by the speed of light.
The third column lists the secant of the angle of the secondary particle with respect to the vertical. One was at 43° to the left of the primary particle's line of flight and was minimally ionizing and non-penetrating. The other was at 3° to the right of the primary particle's line of flight • was ionizing minimum and penetrated a slab.
The secondary particle causing the large interaction was also charged and located at . 0° to the primary particle's line of flight. The Castagnoll(16.)£ formulation yielded a calculated value for the energy of the small interaction of 31 Bev. In the first category of general agreement that the energy of the minor interaction was less than 10 Bev, there were fifteen (IS) cases.
The entire leneth path was thus measured from the fiducial reference to the top of the plate above the second interaction. The two cases of large dispersion in the first interaction may also be internal. involved to the point of a second nuclear interaction. The mean free path value was high compared to Brenner and Williams (ZO) results.
Appendix: C, and angles g and 9 are measured relative to the primary particle's flight line.
The m method of maximum likelihood can be used to distribute the ranges up to the nuclear interaction point11 when the length of the gate to observe such interactions is finite. This method is partially necessary when the gate length is only slightly larger than the average range of the particle to the point of nuclear interaction. Let us assume that the number of primary particles dNt<'x) at a distance dx is proportional to the total number of primary particles ~t(x) and dlatan.:e • dx • The conantant of proportionality will obvlot13ly turn out to be 1/Le , l.
The ratio in equation 3 represents the differential probability, d.P(x), of observing a primary particle within the gate length u Nf. Define the probability function as the expression inside the parentheses on the right side of Equation 16.
The maximum probability procedure consists of finding the parameter Lc • that maximizes the probability function, L • Due to the nature of the product, it is more convenient to maximize ln L •. The standard deviation, q, is given in terms of the second derivative of the probability function as follows.
