Исследование фото- и электроядерных реакций в области энергий до 4,5 ГэВ на установке "Дейтрон" тема автореферата и диссертации по физике, 01.04.16 ВАК РФ

3utAMt"j:Vi

YEREVAN PHYSICS INSTITUTE

On the rights of manuscript

RAPHAEL DEMIRCHYAN

INVESTIGATION OF PHOTO- AND ELECTRONUCLEAR REACTIONS IN THE ENERGY RANGE UP TO 4.5 GeV CN THE "DEUTERON" SET-UP

Speciality: 01.04.16 - Nuclear and Particle Physics SYNOPSIS

of.thesis of candidate of physical and mathematical sciences

YEREVAN - 1994 REPUBLIC OF ARMENIA

The research work is accomplished at Ytrevari Physics Institute

Supervisor: Egiyan K.Sh.

Doctor of Physics and Mathematics

Official opponents: Ava!-;ian R.H. (YerPhI)

Doctor of Physics and Mathematics, Correspondent Member of NAS RA

Maloyan A.H. (XPhI)

Candidate of Physical and Mathematical

Sciences

Leading organization: Yerevan State University

The thesis will be defended on July £ , 1994 at 14 o'clock at the session of the Specialized Council "D 034.03.01 at Yerevan Physics Institute (375036, Alikhanian Bros. St.2, Yerevan, Republic of Armenia)-

The thesis is available in the library of YerPhI The synopsis is distributed on May -¿3, 1994

V.A. Shahbazian

Scientific secretary of the Specialized Council, Candidate of Physical and Mathematical Sciences

GENERAL CHARACTERISTICS

Ictualitv. The discovery of scale-invariant properties of re-'istic nuclear reactions in the early 70-ies initiated in— ! experimental and theoretical investigations of processes secondary particle production in the kinematical region foi— mi (KFR) for scattering on nucleon in rest. According to the ;hesis on cumulative effect (CE) [13, the inclusive spectra irticles produced in KFR are universal and are independent of jeometrical properties of colliding particles, but are due to characteristics of nuclear matter. Historically, the dis-"y of the phenomena of limiting fragmentation and scaling in inelastic eN—scattering preceded the hypotheses on CE and ?ar scaling. Transference of the scaling conceptions into the I of nuclear reactions has an important peculiarity! as dist-from elementary collisions, when scaling is theoretically »ved at asymptotic energies, the hypothesis on nuclsar LF nes scaling already at few GeV energy of incidence. Such fea. ities of experimental investigations make NLF a unique «ay tploring the fundamental properties of hadronic matter ex->ed in the nontrivial structure of nuclei. In this respect, special importance «re the photo- and electronuclear reac— ¡. The advantages of these investigations owe to the essen-character of interaction of electromagnetic radiation with ■is developed theory of QED, relatively 'weak interaction <ing to probe the whole volume of nucleus, etc. In the middle of ttie 80-ies, the basic regularities of MS on front particle beans were experimentally stated, in particu-in investigations with incident photons with GeV on the

-imental setup "Deuteron" at YerPtil. However, there was no late theoretical explanation of the phenomenon. There arose -ous models of particle production in KFR based on different Leal conceptions, such >s short—range nuclear correlations I, quark bags [3], fluctons [6], final state interactions etc. In virtue of the fact, that there are no unambiguous laches to the theoretical understanding of NLF based on

himple ínclusivif reactions, there arises a necessity in mc r¡e>tai3ed and purposeful measurements. In this manning, the corr lation processes in electronuclecr reactions stand alone. whi Qive an additional flexibility to investigations expressed in t pos^ibj1 itv of an independent variation of the energy and momc-f, Him tranc.ff?rr(?d to nucleus.

A :iajnr program of piiperimental investigations of nucle naitF^f prnpF'r t if*^ short distances in coincidence processes lj]fi:I rof^flgmentatitin is adopted in YerPhl. The first result« ri < TitiT a t i ve proton elprtroproductici E93 measurements we

Purpn^^ - The? main goals of the th^is area

Construct ion and analysis of operation of "Deuteron" « "!>puteron-2" setups for investigation of photo- and electrofra (rent^tion of nuclei; simulation of the main systems and physic data processing; analysis of physical potentialities of setups.

2. Calculation of the quasideuteron mechanism's contributi into cumulative photoproton production using the results fr "Deuteron".

3. Experimental investigation of deuteron photoproduction nuclei at Emax = 4.5 GeV and data analysis.

r

4. Investigation of the energy spectra of cumulative protc in coincidence with scattered electrons measured first "Deuteron—2" based on calculations according to the short—ran nucleón correlation model (SRNC).

Scientific novelty.

-In the energy range of E^ > 1.2 GeV the first experiment investigations of the yields of deuteron photoproduction on nu lei at Ep** = 4.5 GeV have been carried out. The angular, snar and «-dependences of the yields of A(y,d)X reactions are obtai ed. The results are compared with the experimental date processes with incident hadrons and predictions of a nuaber theoretical models;

-Quantitative estimations of the quasideuteron mchanisc contribution into the total process of cumulative protons phot production are obtained;

-The energy spectra of cumulative protons in >2C(ere'p)X » action are calculated according to the model of pair correlatic

Z

SRNC and cospared with the deta obtained on "Deuteron—2".

Practical Ute. The constructed "Deuteron—2" setup can serve . en experimental basis for iong-ter» physics experiments.

Analysis of the principles of operation of experimental set— (S, simulation and calibration as well as physical information adout and data processing procedures can be used in further e;:— 'riments in YerPhT.

The experimental data obtained can be used for reaction yield tinMtion= in experiments an deuteron photoproduction and in slyi'tng the mechanism of fast deuteron production on nuclei.

The physical potentialities of "Deuteron-2" are analysed in -del approximation in investigations of urgent problems of yresi. future.

Approval. The basic material of thasis has been reported in dinars he'd in YerPhI, ITFP, JINR, all—Union workshops on raiting fragmentation of nuclei (Moscow (ITEP)- 1985. 1987} ■rPhl {Nor—Amberd)— 1984, 1986, 19BB).

Structure of thesis. The dissertation consists of an troduction, two parts with two chapters in each, a Conclti«iior. d References. The work is presented on 134 pages, including 47 gures, 11 tables and 80 references.

Publicaticns. The main contents of thesis is presented in 10 blirations.

CONTENTS OF THESIS

n Introduction is shown the actuality of investigations carri— out, the purpose is formulated and the structure and bri»f ntents of thesis are presented. The first part consisting of e first two chapters is devoted to the investigations of photo-clear processes. The next two chapters comprise the second part voted to the investigations of electronuclsar processes. n Chapter 1 is described the two—arm experimental setup euteron" designed for investigations of inclusive photonuclear actions on solid targets. The beam line is described. The main aracteristics of targets used are presented. The secondary par— cles produced in target were detected by a scintillator range

detector (RD) and a magnetic spectrometer (MS) mounted on tw parate mobile platforms. The detection angles of both of tha can be changed independently within the range." from 20° to with respect to the photon baam direr.! ion.

The RD is a telescope.' of fivt- acintil J ation counters s copper radiator of variable thickness. Particles idcntific in RD is performed by tho (R,dE/dX) method. Tho solid atigl 1.0 mar. The range of detection of proton«; and charged energies is 80-290 MeV and 50-15S MeV, respectively.

In MS the particles are identified by a simultaneous n;ea ment of their momentum and velocity. The momentum is measure charged particles trajectory deflection in magnetic field the help of two hodoscopic systems of scintillation counters particles velocity is determined by a time-of-flight measur at a length of 4.5 m. The MS Maximum solid angle is 1.25 rnsr mentum resolution (VwHM) is 14X. The spectrometer's dete system provides a reliable identification of pions, protons deuterons with maximum momenta up to 1.5 GeV/c.

A detailed analysis of the principles of particles iden cation is performed, the main characteristics, and the resul simulation and calibration of detecting systems of the setup presented.

Chapter 2 is devoted to the investigations of photonuclear actions. The physical data extraction procedure and the meth calculation of correction coefficients are presented at beginning of the chapter, also the systematic errors of mea merits are estimated.

Then the quasideuteron mechanism's (QDM) contribution into cumulative proton (CP) photoproduction is considered. I stated, that for a better understanding of cumulative par production it is necessary to determine the possible cont tions from a number of models. QDM is considered as a simple chanism providing for proton production in KFR. The obtainin the QDM contribution is also important, because this mecha being trivial in the meaning of understanding of nuclear s ture, however is present in experimental investigations o photoproduction as a physical background. Two ways of disint

tion of quasideuteron pairs with a following proton Pfc production in KFR are considered!

a) y * -» " + Pk

b) Y * „N-» it + ...

I-, n + d" -—► n + pfc

directly by incident photons (a) and secondary pions (b) produced in nucleus in primary yA-interaction. The calculation« are carried out for carbon nucleus at E™"* = 4.5 BeV. The yield of the reaction la) is calculated by the numerical integration of the cross section over the bremsstrahlung spectrum of primary photons and momentum of quasideuteron pairs. The reaction lb) is calculated by the Monte-Carlo method according to the cl*«*ical intranuclear cascade scheme. The flu* of secondary pions la obtained using the results of detailed experimental investigations of the fl(j',ni)X reactions CIO,113 carried out on "Deuteron". The results of calculations are compared with the experimental yields of "c(r,p)x reactions £123 measured by RD. Fig.l shows the measured energy and angular spectra of photoprotons together with the results of calculations on quasideuteron photospallation. A conclusion follow*, that the contribution of QDH in this case ia

at & » 90°, T » lOO HeV, and becomes' negligible with p P

increasing detection angle and energy of protons. The comparison of the data from [123 with the results of calculation on thm reaction lb) is shown in Fig.2. fit proton energies from 80 to 100 HeV the considered mechanism's contribution into CP production can not exceed 25%. For higher energies (at 200 HeV) this contribution decreases down to (5-10)X.

The first experimental data on deuteron photoproduction on nuclei in the energy range of E^ > 1.2 BeV are presented in Chapter 2. The yields of A(r,d)X reactions at E^"" » 4.3 BeV measured by IIS of "Deuteron" are given. The angular and A— dependences of deuteron yields from C, Al, Cu, Sn, Pb nuclei at Pd = 0.98 BeV/c in the angular range from 30° to 120° and thm

energy spectra for Al nuclei, at ft m 90° and 90 in the momentum

d

range P. - (O.84-1.23) GeV/c [133 are investigated.

a

A detailed analysis of thm measured data is carried out. Thm

Fig.l

Proton spectra [123 from reaction fiZC —► pX at E^" = 4.5 GeV

a) energy spectra at

& =90° (O) and 160°< □ ) p

b) angular spectra at

T = 100 MeV (A) and p

287 MeV <OV

Solid curves — calculations t the quasideuteron photodisintegration model.

0 01 0ï q.j -j -m 0 cls 1

Fig. 2

Proton angular spectra [121. The solid curves (1-6) show the results of the Monte-Car calculations by the model of pion absorption by the quasi deuterons for proton énergie 80 MeV - ( • ) ( 1 ), 100 MeV -(A)(2), 136 MeV - ( 0 ) (3), 180 MeV - ( 0 )<4), 210 Mev -(y)<5) and 287 MeV - (0)(é respectively.

cci^jr.l'cn »■- • ; .'-i'" i 1 ♦ ■-similarity ?.n -l

I i \n.tv/ 1 ' ?.-V/ ~ ; of th'JSC •)-'■ 1

(¿r.fjuL'ir ;,ívl .V-;. . -^-^^ntu"» . r: L r "i) • The? ^ngu'1. • " \v. t

uc .nc'5 ri ritif.u j>1 h nvr.riant yield's ft s f /f for th:¿

d p

con*>idsrf*d * *»>-i n in rig.3a) • Arresting is the fact, cha'.

R \ncrr.ar;PT) with in~r• detection ingle, and for heavy nuclei

o;.'CGf?ds unity. Thi*i :pcrirnenta? regularity testifies against -1't-rect ir.sch^nis^.s of * v nulative i-'utGron photoproduction. Indeed * in KFR as such mochnniafn could ¿erve the incident photon interaction with multinuclrfon (>3) intranuclear correlation with a fol~ lowing production o f a deuterorv—spectator'. In the case with R > 1 this would mean an excess of correlations with order >3 over the ones with >2, which makes no sense. The same situation takf»s place in hadronic (h,d) processes. Further, the data are compared with the models based on indirect mschetnisms of deuteron production, These are different modifications of the model of coalescence of secondary protons and neutrons produced in interactions of incident particles within nuclei C14, 4, 15, 163 and secondary

picfcup £17} model - The coalescence ) and pickup (h ) coeffici-

c p

ents determined correspondingly from the relations

P.(p> * p (p/2) p (p/2)'* d f> n C

(2)

PAT) « t P (T+e) + p <T+£) 3* d p n p

are tabled versus A, P, and 8., where c is nucleón binding ener-<1 d

gy, p is invariant yield normalized to the total cross section of hadronic photoabsorption on nuclei. The experimental dependences of coefficients x are closer to the coalescence models predictions C15.163.

The comparison of and (h,d) data reveals a great dis-

crepancy in coalescence probability. Thus, in the cumulative re— h y

gion the relation of at = (5—10)» is valid, while the normalized

c c

yields of cumulative protons are approximately the same in both cases. This statement qualitatively agrees to the conception that unlike hadrons undergoing multiple interactions in nuclei, the photons interact only once. So, in the CP photoproduction mechanism there is a process with a suppressed yield which however is dominating in cumulative deuteron photoproduction. As such a me—

0,8 C,2 1,0 o.S M

l.o 0.6

0,2 -

1,0 0,6 c.l o.a

OA

I Mil

-0,5

COS I*,

a)

iJ{W

0 -f

- fp(T.£) - 10s 9

o 0

o °

i- A

"A a ¿s

a J* o

a u

v v V

'o 0 0 0

1.0 -0,5

CCS

Fig. :

cosiS-j

The experimental dependenses of ration

pickup x (c) coefficients versus eni

0 , ftl - 7 , Cu

R s f,/f (a), coalescense * (b) and

dp c

angle at P = 0.98 GeV/c and

0 , sn - A Pb - o

chsnisa ccrjld the process lb). In this approach on:? ccn

qualitatively expijin the A,® I-dependence, and the fiizc? oi ths

d

dfjuteron ffnission ragion £123 is in consistence with tha calculated «53n frea path as 2.6 F of secondary pions in reaction lb).

In Chapter 5 is described the two-arm experimental oatup "D-vHiteron-2" for correlation r?xperiiwints. The setup allows one to carry out investigations on either electron e^ or photon "V" beams (Fig.4).

The setup weighing more than 60 tons is mounted on a mobile platform able to move at a distance of a 9 • from cine beam to tho other. The electron beam characteristics, especially the tims ones, are analyzed. The beam-line magnetooptical system is described, and the results of calculations of beam formation are presented.

The functioning of the integral range spectrometer (IRS), i.e. proton detecting arm, is analyzed. The IRS is a scintillation counter telescope. Particles aré identified using the analysis of energy deposition in a lBcm-thick plastic counter. The spectrometer's energy acceptance corresponds to the kinotic energy range from BO to 200 MeV for protons. The solid angle is 0.1 sr. Employment of scintillation hodoscopes provides an angular resolution of. ±1°. The results of simulation and calibration of IRS are presented.

The magnetic spectrometer of the setup is dscisned for detection of charged particles with ea;'.tn'iii.s up to 2.5 GeV/c. The mo-mcntua is determined by measuring the particle trajectories with tha help of a system of seven multiwire proportional chambers. The n/e rejection system consisting of a gaseous threshold Chorenkov counter and a scintillatoi—lead shower detector is described. The results of M3 simulation and calibration by measuring the electron scattering on hydrogen are presented. Chapter 3 is concluded by the description of the detection system of the setup and the system of physical information readout and processing.

Chapter 4 is devoted to the investigations of electronuclear reactions on the setup "Deuteron-2" designed mainly for investigations of nuclear matter properties at short distances using processes with hadrons in final state. The setup allows to study (e,L'' np) reactions with n > 1 at different G* and v, which do not » fct;uire record energy ana space resolutions. It is shown that fchssc investigations in principle allow to study the averaged nuclear characteristics as well as certain effects in model ¿approximations connected with the influence of nuclear medium on bound nucleon characteristics and revealing of strong pair correlations in nuclei.

A discussion of the CP energy spectra meausered first in electroproduction on "Deuteron-2" [9] is made in this chapter. The experimental data are compared with the results of calculations. Fig.5 shows the measured invariant enrgy spectra of

CP from the ,2C(e,e'p)X reaction at 9 120° ( O ) and 140°

•p

( A )* The data are obtained by integration of the measured C?3 foui—differential cross section

f s (l/P)dV/dn dE = <1/P) 1 ffdV/dO dE dfi dE IdO dE (3)

p pp JJl p p

over the scattered electron variables (Q2=(0.1—0.25) GeV% u=(0-0.6) GeV) . Fig.5 shows also the calculated curves. The dashed curves show the results of calculations including both the direct and spectator mechanisms of electrodisintegration of pair correlations in rest. The,cut-off of the calculated curve in the

region of T as l&O MeV for 140° is of a kinematic character: the p

corresponding scattered electron spectrum calculated according to

no 133

7 ,{GsV)

Fig. 5

he energy spectra of protons from the 12C(e,e'p)X ion. The experimental points relate to 0^=120° < O ) and (A). Solid curves show the total contributions of the pair lation model of SRNC (dashed curves) and A-production ed ones).

the kinematics of pair correlation electrodi^integration is & rely out of the energy acceptance of MS. In the considered model the observed CP yield in this proton energy ranee shaul' explained by the contribution of higher-order r.orrelat (triple and higher).

Two possible secondary mechanisms of CP production dua A-resonance production by virtual photons an Fermi nucleons also calculated: a) absorption of pion (the product of decay A) by quasideuteron pairs, and b) scattering of resonance a! whole Dn nucleón. The dotted curves show the total contribuí of these two processes which is not essential and in the CP er gy range considered makes (10-25)'/. for & = 120° and =sl5X

•P

o

140 . The solid curves show the total CP spectra calculated cording to the model,of pair correlations and A—production. curves follow those predicted by the SRNC model which successl ly explains the CP production in coincidence with scattered el tron in the experiment considered.

In Conclusion the main results of the thesis are summarized:

1. The two-arm setup "Deuteron-2" was constructed for inv

ligations of inclusive photonuclear reactions on solid targets

the energy range up to E™a* = 4.5 BeV. The functioning of

main systems of the setup is simulated and analyzed. The setup

shown to provide a reliable identification of pions, protons

deuterons in a wide angular range of particle detect o o

0 - 20 —160 and momenta;

-in the range detector: P = 0.4-0.8 GeV/c, P = 0.1-0.25

p n

GeV/c with an accuracy of (1-10)% and within a solid angle LQ~* sr.

-in the magnetic spectrometer: P^ = 0.1-1.3 GeV< P = 0.6-1.3 GeV/c, PJ = 0.8-1.3 GeV/c, with a resolution of j

P a

at FWHM and within a solid angle of 1.5 sr.

2. The contribution of the quasideuteron mechanism into t cumulative proton (CP) photoproduction is calculated. It is she that in the measured CP yields

a) the contribution of quasideuteron photodisintegration 12C at Emax = 4.5 GeV in the region of p 0.4 GeV/c and & = <¡ does not exceed 5X. This contribution becomes negligible with i

easing p and & ;

p P

b) the contribution of the mechanism of secondary pion ab— irption by quasideuteron pairs in the region of = (0.4-0.5) GeV/c makes =! 207.. This contribution decreases

>wn tD (5-10)% with P increasing up to 0.7 GeV/c; p

3. The yields of deuteron photoprociuction on C, A1, Cu, Sn,

i nuclei fit е""1* = 4.5 GeV have Ьйеп maasured first in the ener— Г

range of E^ > 1.2 GeV. The angular, energy and A-dependences invariant yields of photDdeuterons are close to the analogous ies obtained in reactions with primary hadrons. The comparison the experimental data obtained with the predictions of a num— r of theoretical models and hadronic data shows that:

a) thi? most probable mechiinisn of o'^utoron photoproducticn is ig coalescence fi>i?chanisrc;

b) co>~prri.scn with harironic data r(?vcialri a ^icjni f icant dis— прайсу in Lhr' cumulative iinutcron^, ¿re; ilencrncc1 probabilities

11 - (5-10) ).. which is bel i-^vcci to be? to coalpscencp of

с с

• ::." in ! • Df :"uH J|;! • I.: ' mm •* nf ргм r:.r у h

ti'. s,i? . •:*•. 1». f (rinli.1:^ phntano .intcr^ctiiun cnly mice) .

-'!„ "})f:ut(iron-2" so tup ir. aiiitriicliil tor correlation in—

•.'ЛЛ inn;; in ph-to— г' 'ci.rcn»clr,"r in the nuclc?-

frijiantaticn region. The main bystcm of tl ™. setup are descr— cd, the results of simulation of functioning o? the setup and e results of calibration of its different systems are counted.

4.1 Л largt? acceptance integral ranne spectrometer is const— cted on the basis of a thick (50x50x13 ест") scintillation coun-r capable to dstuct proton3 by the (E,d£/dX) mathod and with an ergy occoptanca iron CO to 200 CteV within a solid angle of

12 cr.

4.2 The magnetic ipL'ctra№tpr allowa to identify scattered ectrons within a it,omentum acceptance of AP/P = 467. (FWHM a 3 X) th ДО = 1.25 msr. The n/e rejection system based on a gasrjou» roshold Cherenkov counter and a load-scintillator sandwich ower detector provides a n/e rejection better than I.V. with sn X efficiency of electron registration at P^< 2.5 GeV/c.

5. An extracted electron beam-line magnetooptical system ie

calculated and conr. Lrui; ted. i'fr ■ uucfa c.w.r.ii • ..iic. analyrEi'd.

6. The physical puten tial i tit>3 ai "Dsutcrur-2" arc." an«-.; ; in modul approximation on the oxowple of soma urgent p" oI»W-:v: investigation oi nuclear raatt«ir properties at short dj.at-nc.c-.-

7. The c>ni?rgy '¿pectni of '.ilectrofj.-oducticii of cumt. ative ] tons measured first on "DKuteron-2" èit £ - 1.94 Gg.'\ 1ar C

tr

studied. Cal cul citions according to the pair correlations mi

with account of the contribution of ¿-production art- carried i

It is shown that the results of calculations are in a good ag

ment with the CP spectra measured at & = 120° and 140°.

op

The main contents of the thesis has been presented in following publications:

1. Alanakyan K.V. , Amaryan M.J., Demirchyan R.A. et al.Setup investigation of cumulative photoproduction of particles nucleiW Preprint YerPht-408(15)-80. Yerevan, 1980

2. Ajvazyan R.B..Alanakyan K.V., Demirchyan R.A. et al. Magn spectrometer of "Deuteron" setup based on multiwire pre tional chambersW Preprint YerPhI~493(36)-81, Yerevan, IS

3. Amaryan M.J., Demirchyan R.A., Egiyan K.Sh. et al. Contri-bution Qf the Quasideuteron Mechanism in Cumulative Pho-toproduction of ProtonsW Prep YerPHI-1030(80)-87.Ye revan, 1987.

4. Alanakyan K.V., Amaryan M.J., Demirchyan R.A. et al. Deut photoproduction on nuclei by bremsstrahlung y—qi atE™°*=4.5 GeVW Preprint YerPH I-749 (64)-87, Yerevan, 198

5. Alanakyan K.V., Amaryan M.J., Demirchyan R.A. et al. Chi teristics of electron beam extracted onto the Deuterc setupW Preprint YerPHI-1035(B5)-87, Yerevan, 1987.

6. Alanakyan K.V., Amaryan M.J., Demirchyan R.A. et al. Ga; threshold Cherenkov counter of "Deuteron-2" setupW Pre| YerPHI—1034(84)—87, Yerevan, 1987.

7. Alanakyan K.V., Amaryan M.J., Demirchyan R.A. et al.Inti Range Spectrometer of the "Deuteron-2" SetupW Pre) YerPHI—1154(31)-89, Yerevan, 19S9.

Ajvazyan R.V.,Alanakyan K.V., Demirchyan R.A. et al.Magnetic Spectrometer of the "Deuteron-2" SetupWPreprint YerPHI-1155(32)-89, Yerevan, 1989.

Amaryan M.J., Demirchyan R.A., Egiyan K.Sh. et al.The "Deuteron-2" Setup for Investigations of Electronuclear Reac-tionsNN Preprint YerPHI-1195(72)-B9, Yerevan, 1989.

D. Alanakyan K.V., Amaryan II.J., Demirchyan R.A. et al.rt/e rejection system of the "Deuteron-2" setupW Preprint YerPHI-1153(30), Yerevan, 1989.

REFERENCES

Baldin A.M. Scale invariance of hadronic collisions and possibility of obtaining of high energy particle beams at relativistic acceleration of roulticharge ionsW T3rief Reports on Physics, 1971, v.l, p.35-39 (in Russian).

:. Bayukov Yu.D., Vorobev L.S., Leksin G.A. et al. Scaling effects et back scattering of protons with energies of few GeV on nucleiW YatJ. Fiz., 1973, v.18, p.1246-1230. Strickman M.I., Frankfurt L.L. Short—range pair correlations in cumulative nucléon production at high energiesW Yad.Fiz., 1979, v.29, p.490-506.

I. Strikman M.I. and frankfurt L.L. Hard Nuclear Processes and Microscopic Nuclear StructureW Phys.Rep-, 19B8,v. 160,p.236.

5. Kondratyuk L.A., Shmatikov V.Zh. Are there Multiquarks in Nuclei ?\\ Preprint ITEP-114, 27p., Moscow, 1983.

i. Burov V.V., Lukyanov V.K., Titov A.I. et al. On the mechanism of cumulative particle production in proton—nuclear collisionsW Preprint JINR-10927, 15p., Dubna, 1977.

7. Kopeliovich V.B. Multiple processes at proton production on nuclei in the region forbidden for kinematics for (NN)-scatteringW Pis" ma v ZhETF, 1976, v.23, p.384-392.

B. Levinger J.S. The High Energy Nuclear PhotoproductionW Fhys.Rev., 1951, v.84, p.43.

9. Alanakyan K.V., Amaryan M.J., Demirchyan R.A. et al.The (e,e'p) Reaction on 1ZC with Backward ProtonsW Preprint

YerPHI—1303C89)—90, Yerevan,1990.

10. Alanakyan K.V. , Amaryan n.J., Demirchyan R.A. et al. Angula dependence of the yield of low-energy n-nesonsW Pis'ma ZhETF, 1980, v.31, p.381.

11. Alanakyan K.V., Anaryan M.J., Demirchyan R.A. et al. n-mesc

+

spectra in the inclusive reaction yC-► n~X induced t

bremsstrahlung }—quanta with »axiom« energy 4.5 6eV\\ Pis*a v ZhETF, 1980, v.32, p.666.

12. Alanakyan K.V., Aroaryan M.J., Demirchyan R.A. et al.On th Angular Dependence of Photoprotons from Nuclei Irradiate with j—Quanta with Maximum Energy 4.5 BeVW Nucl.Phys., 1981 V.A367, p.429.

13. Alanakyan K.V., Amaryan M.J., Demirchyan . R.A. et al Deute- ron photoproduction on nuclei by breraastrahiun y-quanta at E^^.S GeVW Preprint YerPHI-749(64)-87 Yerevan, 1987.

14. Butler T. and Pearson C.A. Deuterons from High-Energy Proto Bombardment of MatterW Phys.Rev., 1963, v.129-, p.836-842.

15. Schwarzschild A. Zupancic C. Production of Tritons, Deutrons Nucléons and Mesons by 30 GeV Protons on Al, Be and F TargetsW Phys.Rev., 1963, v.129, p.854-862.

16. Mekjan A.Z. Explosive Nucleosynthesis, Equilibrium Thermodi namics and Relativistic Heavy-Ion CollisionsW Phys.Rev.C 1978, V.17, p.1051-1070.

17. Bayukov Yu.D., Gavrilov V.B., Gorlanov N.A. et al. Deutera production in proton-nuclear interactions at 7.3 6eV/c\ Preprint ITEP-123, Moscow, 1962.

¿T

:3qminmnJ2tn nmin } Qm^milminrndq tiudqqíqiuíUdm qmldiununjmqqmn

tdjuudtidqq qmjnla[imtimji[mhi djimjiBmimam ijnqmqubqa-v Jiulqqum »JJiZmq Ш44 ijlidm)i2mq mJtmlqüuji vJdqqmijËmHqduli qijfmqulliiuq qmiehultuQdub qmmjîUml) qq QmJimmjiqjimq üdqqáqiuíüdm qml)mi¡ -mdm?du<J> :QdqqdmIiqtmi ln{uiqbdqq:i ijdqqqumudín Jiiluimtliujuuíi qm6m2mum Bijt -tmjMimqu x (d. ¡з-э)эг>1<}т]1фт? juu-.jq;dq pmbqm qiJSmam qq QmliQtuIdq^

:md]i i|dqqIimqt]do qmjiçiul ijdqqdijfaqnl ijqmá (jji tnmuimdq litmbmlnm mbmmuji jiiuumlimbmqd q m ji li ijn mqju umu i{dqqqiul«liut|mmq i]cliutq qi]ímlim3i|ji md)i ijdqqqiufdiudalimuqq J?dml) dilqqqiufdiuiIufimUmqq qmiimti4b<]$ qmjidutimddrmi «£-qudmtql¿» qq QníJujiuldqli djimfriiuduJiminuji qijlmlqlrax)

:uiqq ijdqqjnunqmmn]qm}| tjdqqlqtiuji qmi|mnqm ädmi ijji nqhiqtm 'ijdqqlmrtim Qm{iBm<nn liudqqqudbmq qmlimqdbi|n nqhi?q<J dqqquifcbaui -mpqjimq Jiulqdmuiml) 'adqqâqiutlidm çm)i£mmn qq qm]iqiuldqti qqduqnmjimdi)m,Q :jiiuSh>qli t^iffa ç-fr = fdqqlmrtiui qml)mdmdmvdui{i qi]3mum qmjidmumawa<¡;

i]dqqqadmíqli BijdqqfiiuSilji juueltiudijm t^b 3* T < '14 QmJiBmtmlidq'X

¡üdqqáqiutüdm цтрфт? qm/idutimadmii «qudmrq-i,» tiulqçdubinmbo '«jmjidmunidi qq dqql]dm]iZmq qmpdüdqq i]]qUu{i qi)Imqudmfqlnlbmtia juunqBudhi qmjiBmSmamuinu^ «Idqqquinudbi (и]ттПш]1Ш|}

••UdqbUralimtadmdm qmjiIimZp q qmjiBmmn <Jdqqlm(]im qmljmíiiíbijífc qmíjmqSdq}i mdji qmjiilq ijdqqäqiufüdrn цтрфт? qq ijmjidqj ¡ndqqaqmHi -dm qmpdujimqmyilmnm q qmjiüulimlqtiuji iJdqqBímbqmq dqddmin Eqmdq 'Sqiuld -îuçtuldqji ijäqminmn|2m 'Uqiuldiudbmdmiiq i]dqq3qmímt]mddmn «^-qudmfq-i,» q «qudrntq^ çmtiçliqmn jiiu-*j<£dq çmjmqmmnjmq dmpmq ijdqqliminmtaq ijm{i2q qq qmjidqy :3qmjimul>mmq4 iJdluiqUq i(í rn i( ßmuiqq j» b mil<¡; iJ1¡iuSi1ji ijpumm luijigdub -mdi] [ludqqqaUmfiql^ q frudqqquuiœj; qmliraqdbf|n Qmjidifliq ' fldqmmmnJSn

:qm[»äiuqml|mdb çmjidqd3q;i qmqm £jg q limmuri¡m -j-j 'dinliq ¿f lmíumdqq ,nid]i Uijbmlnui 1 çmjidlimd

-ш2 dilqmmmnJSi) :Bi}¡iqin& qij<itiiurçiï:iimt3b q Ei)qmdmSUq]i "BiJüqnmji íuljdq liuí] -mqiudmhs n]iulb qm!|miul)dq 'BiiqsurriliuçmdLjii çiiilijibrnli ¡lqiurdimiunjmqquii)

ШЬ 'lyitlí .'íliJo'íH! «4UJS«AJP

^j£)4û«3Cïimu -usu's

inoyjaoQ-t ajquvían nqorsssou

ДЕМИРЧЯН РАФАЕЛ АРТУРОВИЧ

ИССЛЕДОВАНИЕ ФОТО- И ЭЛЕКТЮЯДЕРШХ РЕАКЦИЙ В ОБЛАСТИ ЭНЕРГИЙ ДО 4.5 ГзВ НА УСТАНОВКЕ "ДЕЙТРОН"

Диссертация состоит из введения, двух частей по две главы в каждой, заключения и списка литературы. Работа изложена на 134 страницах машиналисного текста, включая 47 рисунков, II таблиц и 88 наименований цитируемой литература.

Работа посвящена исследованиям фрагментации ядер первичными фотонами и электронами. Приведены описания созданных в ЕрФИ экспериментальных установок "Дейтрон" и "Дейтрон-2", предназначенных даы этих исследований. Представлены анализ принципа работ установок, результаты моделирования и калибровки отдельных систем. Приведены процедур! получения и обработки физических данных.

Выполнены расчеты вклада квазидеатронного механизма в процесс фотообразования кумулятивных протонов с использованием экспериментальных данных, подученных на установке "Дэйтрон".

Представлены перше в области > 1.2 ГэВ экспериментальные данные по фотообразованию дейтронов на ядрах при е™"* =4.5 ГзВ. Подробно анализированы полученные результаты, проведены сравнения с данными, полученными с первичными адронами и с предсказаниями ряда теоретических моделей.

В модельном приближении проанализированы физические возможности установки "Дейтрон-2" в исследованиях свойств ядерной материи на коротких расстояниях на примере некоторых актуальных задач ближайшей перспективы.

Проанализированы энергетические спектры кумулятивных протонов в реакции ,2с(е,е'р)х, впервые измеренные в электророждении на установке "Дейтрон-2". Экспериментальные данные сравниваются с результатами расчетов по модели парных короткодействующих нуклон-ных корреляций с учетом д-образования.

По результатам диссертации опубликовано десять работ.