,,lrl ,accelerators ,,the #ahd-;,,inch ,,synchrocyclotron ,,lawrence ,,radiation ,,laboratory ,,university ,,of ,,california1 ,,berkeley1 ,,california ,pub4 ,no4 #b;d #e,m ,june #aifd ,illustration3 ,synchrocyclotron ,building ,contents ,page ,,the #ahd-;,,inch ,,synchrocyclotron #b ,,principle ,,of ,,operation ,,of ,a ,,conventional ,,cyclotron #c ,,the ,,principle ,,of ,,phase ,,stability #f ,,design ,,and ,,construction ,,of ,,the #ahd-;,,inch ,,synchrocyclotron #h ,magnet #h ,vacuum ,system #i ,ion ,source #aj ,radiofrequency ,system #aj ,internal ,targets and ,beam ,extractor #ab ,,cyclotron ,,experiments #ae ,nuclear ,physics #ae ,biophysics #ah ,nuclear ,chemistry #ai ,,bibliography #bj ,,appendix #ba ,,the #ahd-;,,inch ,,synchrocyclotron ,his success with the #fj-;inch cyclotron in #aici led ,dr4 ,e4 ,o4 ,lawrence to propose a much more powerful accelerator1 one which could produce new types of nuclear rearrangements and even create particles4 ,grants totaling #a1bbe1jjj permitted work to start on the #ahd-;inch cyclotron in ,august #aidj4a ,it was designed to accelerate atomic particles to an energy of #ajj million electron volts 7,mev71 five times that possible with the #fj-;inch machine4 ,illustration3 ,fig4 #a4 ,the electromagnet under construction during the period #aidj to #aidb4 ,before the new cyclotron could be finished ,world ,war ,,ii began4 ,construction on the cyclotron was therefore halted4 ,however1 because of interest in separating the isotopes of uranium by the electromagnetic method1 work on the giant magnet continued at an even faster pace4 ,this magnet would contain #cgjj tons of steel in its yoke and pole pieces1 and #cjj tons of copper in its exciting coils 7,fig4 #a74 ,by ,may #aidb the magnet was completed4 ,during that summer it was used in a pilot plant to separate the first significant amounts of ,u#bce ever obtained4 ,the #ahd-;inch magnet remained in use in a research and development program at ,berkeley until the end of the war1 supplying information to ,oak ,ridge1 ,tennessee1 where a large separation plant had been erected4 ,construction on the rest of the cyclotron was resumed in #aide4 ,by that time a new principle had been discovered which made it possible to obtain ion beams of much higher energy than originally hoped for4 ,yet a considerably lower accelerating voltage could be used4 ,this important discovery was made independently by ,dr4 ,v4 ,veksler in ,russia and by ,dr4 ,edwin ,m4 ,mc,millan1 present ,director of the ,lawrence ,radiation ,laboratory4 ,before attempting to discuss this principle1 we should first review the operation of a conventional cyclotron4 ,,principle ,,of ,,operation ,,of ,a ,,conventional ,,cyclotron ,illustration3 ,fig4 #b4 ,basic parts of a cyclotron4 ,the main parts of a cyclotron are represented in ,fig4 #b4 ,charged particles 7ions7 are accelerated inside an evacuated tank4 ,this is to prevent the beam from colliding with air molecules and being scattered4 ,the vacuum tank is placed between the poles of an electromagnet1 whose field bends the ion beam into a circular orbit4 ,the operation begins when the ions are introduced into the region between two accelerating electrodes1 or dees4#b ,because the ions carry a positive electric charge1 they are attracted toward that dee which is electrically negative at the moment4 ,were it not for the magnetic field1 the ions would be accelerated in a straight line2 instead they are deflected into a circular path back toward the dee gap4 ,by the time the ions again reach the dee gap1 the sign of the electric potential on the dees is reversed1 so that now the ions are attracted toward the opposite dee4 ,as this process of alternating the electric potential is repeated1 the ions gain speed and energy with each revolution4 ,this causes them to spiral outward4 ,finally they strike a target inserted into their path or are extracted from the cyclotron for use as an external beam4 ,the time required for an ion to complete one loop remains constant as it spirals outward4 ,this is because its velocity increases sufficiently to make up for the increased distance it travels during each turn4 ,this means that the electric potential applied to the dees must alternate at a constant frequency1 called the resonant frequency4 ,the resonant frequency f is given by the relationship ,he f --------- 1 7#a7 #bpimc where ,h1 e1 pi1 c1 and m are constants4 ,h is the strength of the magnetic field of the cyclotron1 e is the electric charge carried by the ion1 pi equals #c4ad1 c is a conversion factor1 and m is the mass of the ion4 ,for example1 the resonant frequency for protons accelerated in a #ae1jjj-;gauss magnetic field is #bc4g megacycles 7,mc74#c ,we call such a rapidly alternating potential a radiofrequency voltage and the electronic circuit for producing it a radiofrequency oscillator4 ,the energy ,e of an ion emerging from the cyclotron is given by ,h#b ,r#b e#b ,e ------- ---- 1 7#b7 #b mc#b where ,h1 e1 and m are as defined above1 and ,r is the radius at which the beam is extracted4 ,from this equation we see that for a given type of ion 7where e and m are constant71 the energy depends on the diameter and strength of the magnet1 but not directly upon the voltage applied to the dees4 ,the number of revolutions that an ion can make in a conventional cyclotron is limited to about #gj to #ajj4 ,this is due to a very curious effect3 as an ion is accelerated1 its mass increases6 ,this phenomenon is explained by ,einstein's special theory of relativity 7see ,fig4 #c74 ,referring back to ,eq4 7#a71 we see that if the ion mass 7m7 does not remain constant1 but rather increases1 then the resonant frequency 7f7 decreases4 ,but since the dee potential continues alternating at a constant frequency1 an ion soon begins to arrive late at the dee gap4 ,by the time it has made about #gj to #ajj turns an ion is so badly out of phase that it is no longer accelerated4 ,suppose now that we want to obtain an energy of #aj ,mev4 ,because an ion can make a maximum of about #ajj turns1 the accelerating potential would have to be about #ajj1jjj volts4 ,however1 ,professor ,lawrence hoped to reach #ajj ,mev with the new #ahd-;inch cyclotron4 ,this meant that the accelerating voltage would have to be about #a1jjj1jjj volts4 ,preventing such a high voltage from sparking promised to be one of many formidable engineering problems4 ,illustration3 ,fig4 #c4 ,graph showing how the mass of an object increases as its velocity approaches that of light4 ,,footnotes3 #a ,the grants were as follows3 ,rockefeller ,foundation--#a1aej1jjj2 ,john and ,mary ,markle ,foundation--#be1jjj2 ,the ,research ,corporation--#ej1jjj4 ,the ,university of ,california added a guarantee of #age1jjj to bring the total building fund to #a1djj1jjj4 #b ,in the first cyclotrons the electrodes were shaped like the letter ,d4 #c ,we have the values ,h #ae1jjj gauss1 e #d4h x #aj-aj electrostatic units1 and m #a4f x #aj-bd gram4 ,to find f1 we write #ae1jjj 7#d4h7 #aj-aj f ---------------------------------- 1 #b 7#c4ad77a4f7 #aj-bd 7#c7 #ajaj f #bc4g ,mc4 ,,the ,,principle ,,of ,,phase ,,stability ,fortunately1 ,drs4 ,veksler and ,mc,millan showed that relatively low dee voltages can be used to accelerate ions to very high energies4 ,this is possible if the oscillator frequency is continuously decreased to keep it in synchronism with the decreasing rotational frequency of the ions4 ,this would allow an ion to make many revolutions without becoming out of phase4 ,this principle of phase stability was experimentally verified with the #cg-;inch cyclotron before being incorporated into the design of the #ahd-;inch machine4 ,because it utilizes this principle1 this machine has usually been referred to as a synchrocyclotron or frequency-modulated cyclotron4 ,however1 it is sometimes called simply a cyclotron4 ,the #ahd-;inch synchrocyclotron was first operated in ,november #aidf4 ,with a maximum dee voltage of only #bj1jjj volts1 it accelerated deuterons to #aij ,mev and alpha particles to #chj ,mev4#d ,in #aidi it was modified to permit production of #cej-,mev protons also4 ,between #aiee and #aieg the synchrocyclotron was rebuilt so that now the following energies can be obtained3 ,protons ,deuterons ,alpha ,particles ,helium-#c nuclei#e ------- --------- --------------- --------------- #gcj ,mev #dfj ,mev #iaj ,mev #aadj ,mev ,in reaching an energy of #gcj ,mev a proton1 for example1 makes #ge1jjj revolutions in just #f milliseconds 7msec74 ,it travels a distance of #dej miles and attains a velocity of #aeb1jjj miles per second1 or #hb of the speed of light6 ,during this brief journey its mass increases #ge1 giving very convincing evidence for the validity of ,einstein's theory4 ,similar data for other ions may be found in the appendix4 ,,footnotes3 #d ,a deuteron is the nucleus of an atom of heavy hydrogen and contains one proton and one neutron2 it carries a single positive electric charge4 ,an alpha particle is the nucleus of a helium atom and is made up of two protons and two neutrons2 it carries two positive charges4 #e ,the machine is equipped for helium-#c operation1 but to date it has not been used for that purpose4 ,,design ,,and ,,construction ,,of ,,the #ahd-;,,inch ,,synchrocyclotron ,magnet ,during the rebuilding of the cyclotron1 the diameter of the magnet pole pieces was increased from #ahd to #ahh-c_/d inches4 ,also1 the pole gap at the center was reduced from #ba to #ad inches4 ,these changes increased the weight of steel in the magnet from #cgjj to #djjj tons4 ,the main exciting coils1 which contain #acjj turns of copper-bar conductor each1 were not altered4 ,two auxiliary coils containing #dbe turns each were added4 ,this brought the total weight of copper from #cjj to #cdj tons4 ,the coils are layer-wound around the pole pieces close to the pole gap4 ,other data about the coils are given in the appendix4 ,the effect of these modifications was to increase the field strength at the center of the pole gap from #ae1jjj to #bc1djj gauss4 ,this increase made it possible to obtain the higher-energy ions4 ,power is supplied to the coils by two motor generator sets1 which produce the direct current required for a steady magnetic field4 ,the direct current from the motor generators is regulated so that the magnetic-field fluctuation is less than one part in #aj1jjj4 ,this is necessary if one wants an external beam of nearly uniform energy4 ,in order to prevent the beam from becoming unstable and striking the dee1 the magnetic field must be strongest at the center and decrease radially 7,fig4 #d;a74 ,with flat pole faces the field does not decrease uniformly4 ,to give the desired rate of decrease1 the pole faces are shimmed with concentric steel rings of varying thickness1 as shown in ,fig4 #d;b4 ,in a radially decreasing magnetic field1 the lines of magnetic flux bow outward1 as represented in ,fig4 #d;b4 ,ions moving in a magnetic field are deflected at right angles to these flux lines4 ,ions above the midplane of the cyclotron are directed downward2 those below the midplane are directed upward4 ,in this way an ion oscillates about the midplane and vertical focusing is achieved4 ,illustration3 ,fig4 #d4 7a7 ,plot of magnetic-field strength vs radius4 ,the field strength decreases gradually out to a radius of about #hc-;in41 after which it falls off sharply4 ,this point marks the maximum usable radius for particle orbits4 ,further out they are unstable4 7b7 ,magnetic flux lines are represented as broken arrows1 and focusing forces as solid arrows4 ,an ion above the midplane is directed downward1 while an ion below the midplane is directed upward4 ,radial focusing is accomplished in a somewhat analogous manner4 ,if the magnetic field decreases with radius1 radial restoring forces are established4 ,an ion at too large a radius is directed inward1 and an ion at too small a radius is directed outward4 ,in this fashion1 the ion oscillates about the synchronous orbit4 ,thus1 radial focusing is achieved4 ,vacuum ,system ,the vacuum tank 7acceleration chamber7 is a steel box #bj x #be ft and #d ft high4 ,it is evacuated to a pressure of #aj-e millimeter of mercury 7about one #ajj-millionth of atmospheric pressure74 ,the pumping equipment consists of six oil-diffusion pumps and four mechanical vacuum pumps4 ,the pumping speed of the six #bj-;in4 oil-diffusion pumps is a total of #bj1jjj liters_/sec4 ,ion ,source ,the ion source is a simple arc-type4 ,hydrogen gas is allowed to leak into the ion-source enclosure near a tungsten filament1 which is heated to incandescence4 ,electrons emitted by the filament knock off electrons from hydrogen atoms1 leaving free protons4 ,the protons then escape into the acceleration chamber through a hole in the ion-source housing4 ,once inside1 the protons are accelerated by the dee potential4 ,deuterons or alpha particles are obtained in a similar fashion using deuterium or helium gas in place of hydrogen4 ,radiofrequency ,system ,the #ahd-;inch synchrocyclotron has a single dee instead of the double-dee arrangement described above for illustrative purposes4 ,the accelerating electric field is developed between the dee and a dummy dee which is grounded to the vacuum tank4 ,using a single dee does not change the principle of operation1 yet it offers the advantage of allowing more space for auxiliary equipment inside the vacuum tank4 ,also1 the construction is much simpler4 ,the dummy dee is not essential for operation1 but it does improve performance4 ,illustration3 ,fig4 #e4 ,radiofrequency cycle for accelerating protons4 ,sixty-four such cycles are repeated each second4 ,radiofrequency power is supplied to the dee by a vacuum-tube oscillator4 ,the frequency of oscillation must decrease during the acceleration cycle1 as indicated above4 ,for protons1 the frequency at the start of acceleration is #cf megacycles 7,mc74 ,at the end of acceleration the frequency is only #ah ,mc 7see ,fig4 #e74 ,this change in frequency is achieved by varying the electrical capacitance in the tuned circuit of the oscillator4 7,this is what you do when you dial a different station on a radio47 ,this tuned circuit1 which is called the cyclotron resonator1 is shown in ,fig4 #f4 ,illustration3 ,fig4 #f4 ,cyclotron resonator4 ,because the frequency must change over such a wide range 7from #cf to #ah ,mc71 the electrical capacitance must be varied by a factor of #bj to #a4 ,this is done by a variable capacitor of unique design4 ,it resembles two giant tuning forks4 ,as the blades of the tuning forks vibrate1 the capacitance is alternately increased and decreased by the required amount4 ,these two tuning forks must be kept in step with great precision4 ,this is to prevent the oscillator from exciting lateral rf resonances4 ,with a cyclotron of this size1 this is a problem4 ,these resonances1 if excited1 would cause loss of beam4 ,the method for keeping the blades moving together is as follows3 ,the blades are made to vibrate at their resonant frequency1 which is approximately #fd cycles per second4 ,one set of blades operates at its natural frequency as a tuning-fork oscillator4 ,the second set of blades is driven from an amplified sample of the signal from the first2 its natural period is adjusted automatically to equal that of the first4 ,the amplitude of each set is regulated to within #j4jjc in42 the phase angle between the blades is regulated to within #a deg4 ,ions are accelerated only when the radiofrequency is decreasing 7,fig4 #e74 ,the remaining portion of the cycle is dead time4 ,thus1 #fd pulses1 each of about #ejj microseconds' duration1 are obtained every second4 ,the average ion current of a pulsed beam is much less than for a continuous beam1 such as that obtained from a conventional cyclotron 7see ,table ,i74 ,this is part of the price paid for higher energies4 ,internal ,targets and ,beam ,extractor ,the simplest target is one placed inside the vacuum tank where the circulating beam will strike it4 ,the target may be any substance that the physicist or chemist wants to irradiate4 ,the target material is attached to a movable probe4 ,if the experimenter wants to use the full-energy beam1 he places the target at the maximum usable radius of the circulating beam 7#hb inches74 ,however1 if he desires to use ions having less than the maximum energy1 he inserts the target further into the cyclotron so that it is intercepted sooner4 ,,table ,i ,comparison of external-beam energy and current for a synchrocyclotron and a conventional cyclotron ---------------------------------------- --------------------- #ahd-;,inch ,synchrocyclotron ------------------------- ,protons ,deuterons ,alpha particles ------- --------- --------------- ,beam energy -- maximum 7,mev7 #gcj #dfj #iaj ,beam intensity -- peak current 7mua7#f #abj #abj #dj ,beam intensity -- average current 7mua7 #j4ge #j4ge #j4be #fj-;,inch ,cyclotron ----------------- ,beam energy -- maximum 7,mev7 #ab #bd #dh ,beam intensity -- peak current 7mua7 #ajj #aej #ajj ,beam intensity -- average current 7mua7 #gj #hj #fj ---------------------------------------- --------------------- #f mua microampere ,illustration3 ,fig4 #g4 ,plan view of the cyclotron1 showing the method for obtaining an external beam of protons1 deuterons1 or alpha particles4 ,some experiments require an external beam of protons1 deuterons1 or alpha particles4 ,a beam of this type can be brought out of the machine by means of a ,le,couteur regenerator 7,fig4 #g74 ,the construction of the regenerator is very simple4 ,it is made of a number of steel laminations of various sizes4 ,what the regenerator does is perturb the magnetic field of the cyclotron at one radial position4 ,each time the beam passes through the regenerator it receives a kick4 ,with each kick the beam builds up its radial amplitude1 until finally it enters a magnetic channel4 ,this channel focuses the beam and steers it outside the main magnetic field4 ,once outside1 the beam travels through an evacuated tube1 which is integral with the main vacuum tank4 ,by means of a steering magnet1 the beam can be sent into either the physics cave or the medical cave4 7,these experimental areas are called caves because they are rooms inside the massive concrete shielding wall47 ,other experiments may require an external beam of mesons4#g ,a meson beam is obtained in the following way 7,fig4 #h73 ,a movable target such as a block of carbon is placed inside the cyclotron near the end of the outward-spiraling proton beam4 ,when the proton beam hits this target1 a shower of mesons is produced4 ,these mesons are bent in various directions by the main magnetic field4 ,some of them pass through a thin metal window in the vacuum-tank wall and are focused by a magnetic lens into a beam4 ,this meson beam then travels through a hole in the concrete shielding wall into the meson cave4 ,the maximum intensity of this extracted meson beam depends on both the charge and energy desired4 ,beams of more than #ajj1jjj mesons per second have been obtained through an aperture #d x #d in4 in the shielding wall4 ,,cyclotron ,,experiments ,nuclear ,physics ,about #hf of the operating time of the #ahd-;inch synchrocyclotron is devoted to experiments in nuclear physics4 ,most of the experiments study the production and interaction of pi mesons4 ,these particles are considered to be essential factors in the intense but short-range forces that bind the nucleus together4 ,the three types of pi mesons are designated according to their electric charge as pi1 pi#j1 and pi-4#h ,these mesons materialize only in high-energy nuclear collisions4 ,illustration3 ,fig4 #h4 ,method for obtaining external meson beam4 ,of great importance are those experiments that determine the probability of producing each of the three types of mesons in a nuclear collision4 ,this type of experiment is repeated for different beam energies and target elements4 ,other experiments measure the energy and direction of emission of pi mesons from a target4 ,illustration3 ,fig4 #i4 ,a typical experiment4 ,scintillation counters at ,a1 ,b1 ,c1 ,d1 and ,e record the passage of charged particles4 ,a typical pi-meson experiment is represented in ,fig4 #i4 ,the purpose of this experiment was to detect the spin directions of protons as they are knocked out of a liquid hydrogen target by a pi-meson beam4 7,like the earth1 a proton spins on its axis47 ,an extracted proton beam from the cyclotron enters the physics cave from the left1 striking a polyethylene target and producing pi mesons4 ,a beam of these mesons is formed by a series of two bending magnets and three focusing magnets4 ,this beam passes through a carbon absorber to remove unwanted particles4 ,the meson beam then strikes the liquid hydrogen target4 ,a few of the incoming mesons scatter1 knocking protons out of the liquid hydrogen4 ,scintillation counters at ,a and ,b record the passage of a proton1 thus defining its direction4 ,the scattered mesons are counted by a scintillation counter at ,c4 ,a few of the protons scatter off the carbon target and are detected by counters at ,e and ,d4 ,from the detection of such events1 the spin directions 7polarization7 of the recoil protons can be analyzed4 ,in this way1 more is learned about the fundamental pi-proton interaction4 ,further studies of the interactions of pi mesons are made in the meson cave4 ,other experiments performed there are concerned with mu mesons4 ,the mu meson 7muon7 is a particle created in the decay of a pi meson and is the principal constituent of cosmic rays striking the surface of the earth4 ,the muon is unstable1 eventually undergoing a radioactive decay into an electron4 ,although the muon does not experience nuclear forces1 it can interact weakly with nuclei4 ,the behavior of the muon is well understood1 but its role as one of the elementary particles is unknown4 ,that is1 if the muon did not exist1 what effect would this have on the structure of matter8 ,the answer to this question1 among others1 is being sought by physicists using the #ahd-;inch cyclotron4 ,biophysics ,experiments in biophysics are conducted in the medical cave4 ,in these the interest lies not in nuclear interactions but in the effect of ionizing radiation on living tissue4 ,high-energy beams of particles can be used for selective destruction of specific areas of the brain4 ,this permits physiological mapping of the functions of the brain in experimental animals4 ,it further offers a therapeutic approach to the treatment of brain tumors4 ,one of the important investigational programs is concerned with the relationship of the pituitary gland to the growth rate of certain cancers and to some endocrine disorders4 ,nuclear ,chemistry ,for techniques of radiochemistry to be employed successfully1 high interaction rates 7and therefore high beam intensities7 are needed4 ,for this reason1 chemistry targets are usually inserted right into the cyclotron so that they can be bombarded directly by the circulating beam4 ,after the bombardment is completed the target is removed from the cyclotron4 ,it is then taken to a chemistry laboratory and subjected to detailed chemical procedures4 ,individual elements are removed1 and the radioactive isotopes of each element are identified by quantitative counting techniques4 ,in some cases a mass spectrometer is used to analyze the products4 ,many deductions about the nature of the breakup of the target nucleus can be drawn from the pattern of the observed radioactive products4 ,sometimes the nucleus splits almost in half4 ,this is called fission4 ,more frequently smaller parts of the nucleus are split off4 ,two general types of reactions1 known as spallation and fragmentation1 are distinguished4 ,one of the goals of this research is to learn more about the constitution of the nucleus and of the forces which bind the particles in the interior of the nucleus4 ,,footnotes3 #g ,mesons are elementary particles intermediate in mass between the electron and proton4 #h ,it may be interesting to note that the pi#j meson was discovered with this cyclotron in #aiej4 ,this was the first particle to be discovered with an accelerator4 ,all particles that had been previously discovered were observed first in cosmic rays or some other form of natural radiation4 ,,bibliography #a4 ,gerald ,a4 ,behman1 ,particle ,accelerators3 ,i4 ,bibliography1 ,,ii4 ,list of ,accelerator ,installations1 ,,ucrl-#hjej1 ,january #a1 #aieh4 #b4 ,samuel ,glasstone1 ,the ,acceleration of ,charged ,particles1 in ,sourcebook on ,atomic ,energy1 ,second ,edition 7,van ,nostrand1 ,princeton1 #aieh71 ,ch4 ,,ix4 #c4 ,m4 ,s4 ,livingston1 ,high-,energy ,accelerators 7,interscience ,publishers1 ,new ,york1 #aied74 #d4 ,m4 ,stanley ,livingston and ,edwin ,m4 ,mc,millan1 ,history of the ,cyclotron1 ,physics ,today #ab1 #ah-cd 7,october #aiei74 #e4 ,e4 ,m4 ,mc,millan1 ,particle ,accelerators1 in ,experimental ,nuclear ,physics1 ,emilio ,segre1 ,editor1 ,vol4 ,,iii 7,wiley1 ,new ,york1 #aiei71 ,part ,,xiii4 #f4 ,bob ,h4 ,smith et al41 ,the ,electrical ,aspects of the ,,ucrl #gdj-,mev ,synchrocyclotron1 ,,ucrl-#cggi ,rev41 ,october #b1 #aieg4 #g4 ,robert ,l4 ,thornton1 ,frequency-,modulation and ,radiofrequency ,system for the ,modified ,berkeley ,cyclotron1 ,,ucrl-#ccfb1 ,april #c1 #aief4 #h4 ,robert ,r4 ,wilson1 ,particle ,accelerators1 ,scientific ,american #aih1 #fd-gf 7,march #aieh74 ,,appendix ,,summary ,,of ,,specifications ,present fields of research of time -------------------------- --------- ,nuclear physics #hf ,nuclear chemistry #b ,biophysics #ab ,scheduled operation #aef hours_/week ,performance ,internal ,beams ,alpha ,helium-#c ,protons ,deuterons particles ions ------- --------- --------- -------- ,maximum energy 7,mev7 #gcj #dfj #iaj #aadj ,energy spread 7,mev7 #ee ,beam intensity ,average current 7mua7 #j4ge #j4ge #j4be ,peak current 7mua7 #abj #abj #dj ,beam radius1 maximum 7in47 #hb #hb #hb #hb ,time required for acceleration 7msec7 #f #d4e #d4e ,number of revolutions during acceleration #ge1jjj #fj1jjj #fj1jjj ,distance traveled during acceleration 7miles7 #dej #cfj #cfj ,velocity at maximum energy 7 of speed of light7 #hb #fj #fj #fi ,mass increase at maximum energy 7 of rest mass7 #ge #be #be #dj ,range of full-energy particles 7in4 of aluminum7 #cg #ab #g ,external ,beams ,physics cave ,meson cave ----------------------- ------------------- ,protons ,neutrons pi pi pi- ------- -------- ------ -------- --------- ,energy 7,mev7 #gcj #caj #ajjbej #ajj #cjj ,energy spread 7,mev7 #ad #aj #bj #aj #cj ,beam area 7cm#b7 #be #dj #ajjajj #ajj #ajj ,flux 7particles_/cm#b-sec7 #bx#ajaj #ex#aje #ex#ajd #ajjjajj #aejjajjj ,acceleration chamber 7vacuum tank7 ,size length 7ft7 #be width 7ft7 #bj height 7ft7 #d ,material3 mild steel ,operating pressure 7mm ,hg7 #aj-e ,vacuum pumps3 six #bj-;in4 oil-diffusion pumps with #h-;in4 boosters3 one ,beach-,russ #gej-;cfm2 one ,kinney #cjj-;cfm2 two ,kinney #aje-;cfm4 ,pumping speed of oil-diffusion pumps 7liters_/sec7 #bj1jjj ,magnet ,core diameter 7in47 #ahd ,pole-tip diameter 7in47 #ahh4ge ,pole gap at center 7in47 #ad ,magnetic field strength 7gauss7 at center #bc1djj at radius of #hb4b in41 where n #j4b #bb1bge ,weight of steel 7tons7 #d1jjj ,magnet coils ,main coils ,auxiliary coils ---------- --------------- material solid copper hollow copper 7#a_/d x #d in47 7#a-c_/af x #a-a_/af in47 weight of copper 7tons7 #cjj #dj number of turns 7total7 #b1fjj #dbe ampere turns #a4i x #ajf #a4a x #ajf current 7amp7 #afjj #bhjj voltage 7v7 #eej #efj power 7kw7 #ijj #afjj coolant oil water ,radiofrequency system ,dee system number of dees #a size length 7in47 #abf width 7in47 #ahj height 7in47 #dh material3 #a_/fd-;in4-thick copper1 stretched over a stainless steel frame dee aperture 7in47 #d-c_/af ,oscillator type3 self-excited grounded-grid #aj tube3 one ,machlett ,,ml#efha dc input1 operating condition 7kw7 #aj dee bias1 maximum dc 7v7 #bjjj ,protons ,deuterons ,alpha particles ------- --------- --------------- rf duty cycle 77 #ch #bh #bh dee-to-ground voltage1 peak 7kv7 #i #f #f ,frequency-modulation system type3 vibrating-reed 7tuning-fork7 capacitor number of units3 two 7two blades each7 blades size width 7in47 #de length 7in47 #cb thickness3 tapered from #a4d to #j4jf in4 weight 7lb7 #ejj vibrational frequency 7cps7 #fd electrical capacitance 7mumuf7 #cjj to #f1ejj peak-to-peak excursion 7in47 #a minimum separation of blade and stator 7mils7 #ej ,protons ,deuterons ,alpha particles ------- --------- --------------- frequency sweep 7,mc7 #cf-ah #ah-ac4e #ah-ac4e ,ion source3 conventional open-arc type ,beam extractor ,le,couteur-type regenerator combined with magnetic channel ,building and facilities ,room dimensions diameter 7ft7 #afj height 7ft7 #ij ,crane type3 radial capacity 7tons7 #cj overhead span 7ft7 #gg ,concrete shielding3 #ae ft thick on sides1 #d ft on top ,history ,design started3 ,january #aidj4 ,construction started3 ,august #aidj4 ,first operation for deuterons and alpha particles3 ,november #aidf4 for protons3 ,december #aidh4 ,rebuilt3 #aiee-aieg4 ,illustration3 ,synchrocyclotron ,building ,transcriber's ,note3 ,the following changes have been made to the printed text3 ,page #ae1 added closing quote 7are called caves because7 ,page #ai1 iostopes corrected to isotopes