Experiments at the ISR

Our presen t genera t ion of par t ic le acce lera tors has revea led an ent i re ly n e w wor ld of sub-nuc lea r spec t ro ­scopy wh ich no one could h a v e an t ic ipa ted w h e n the accelera tors w e r e p lanned . Beyond this observed r ange of resonances and uns t ab l e par t ic les , wh ich is t he l imit of our p resen t knowledge , a new, m u c h more s imple wor ld is expected w h i c h has been called the ' asymptot ic region' , since the scale of energy ex tends to infinity. I t is bel ieved t h a t knowledge of this region migh t be the key to t he u n d e r s t a n d i n g of sub -nuc lea r spec t ro­scopy and t h a t it m igh t revea l more r egu la r behav iour wh ich will be more easily unders tood .

Bigger accelera tors wil l be needed to obta in a full unde r s t and ing of th is region. Bu t in t he m e a n t i m e w e can get a g l impse a t it, as if t h r o u g h a keyhole, by means of t he ISR. We wil l not have beams of j t-mesons, K-mesons or o ther par t ic les of h igher energies ; the collisions be tween h igh ene rgy p ro ton b e a m s will be our only tool. Yet th is should give us a first insight into this n e w r a n g e of energy.

The re a r e a few b u r n i n g ques t ions w e can a l ready ask wh ich reflect our p resen t v iew of this asymptot ic energy range . Bu t w e migh t u n e a r t h some ent i re ly n e w aspects w h e n r e sea rch begins a t t he ISR, for n a t u r e has a lways p roved r i cher t h a n our imaginat ion .

Before descr ib ing some of t he expe r imen t s wh ich a r e conceivable for t h e ISR it is w o r t h m a k i n g a genera l r e m a r k to i l lus t ra te t he scope of the expe r imen ta l possibili t ies.

The so-cal led ' s t rong ' in te rac t ions be tween par t ic les a r e charac ter ized b y two i m p o r t a n t physical var iab les — the tota l energy of t h e colliding system, and the ' t r ansverse m o m e n t a ' of t he secondaries p roduced in the in teract ion. Exper imen ta l ly , it is found tha t , up to the highest cosmic r a y energies , t he chance of observing a secondary par t ic le w i t h a t r ansve r se m o m e n t u m h igher t h a n 300 to 400 MeV/c is ve ry small . Therefore , to s tudy collisions in w h i c h ve ry h igh t r ansve r se m o m e n t a secondar ies a r e p resen t demands ve ry high intensi t ies . The ISR wil l give only low n u m b e r s of collisions. I ts scope is, in general , t he s tudy of p ro ton -nucleon in te rac t ions a t ve ry h igh energies — about 56 GeV in the cen t re of mass sys tem (c.m.s.), equiva len t to a 1675 GeV b e a m on a s t a t ionary ta rge t — producing secondaries a t qu i te smal l t r ansve r se m o m e n t a (say, less t h a n 1 GeV/c). This is of course a r a t h e r genera l r e m a r k and a specific e x a m p l e con t r a ry to it wil l be given la ter .

1. Elastic Scattering Experiments

The s implest (and possibly the first) expe r imen t s for t he ISR a re those measu r ing p ro ton -p ro ton elastic scat ter ing, p + p -> p + p. M e a s u r e m e n t of the m o m e n t a and angles of t he sca t te red pro tons is suf­ficient to identify t he reac t ion k inemat ica l ly . I t m a y

be supposed, a l though it is one of most in te res t ing fea tures of t he e x p e r i m e n t to find out, that , even a t t h e ve ry h igh energies avai lable , t h e elastic sca t ter ing cross-section wil l be a reasonab le fract ion of the tota l c ross-section. If this is so, the elast ic sca t ter ing expe r imen t s a r e by far t he easiest wh ich can be considered.

In format ion on e l emen ta ry par t ic le sca t ter ing says, roughly speaking, someth ing abou t the size and c h a r a c ­te r ( 'hard' or 'soft') of t he colliding objects. More specifically, m e a s u r e m e n t s of angu la r d is t r ibut ions a n d the energy dependence of t he scat ter ing, toge ther w i t h some theore t ica l ideas, give some clue as to t h e mechan i sm of the sca t te r ing process.

At energies in t he GeV range , p - p elastic sca t te r ing is la rge ly diffraction or shadow scat ter ing caused b y the s t rong absorpt ion of t he p ro ton waves by the m a n y possible inelast ic or p roduc t ion processes. The a n g u l a r d is t r ibut ion of diffraction sca t te r ing is ve ry sha rp ly peaked in the fo rward direct ion so tha t most of t h e sca t te r ing is concen t ra ted in a ve ry n a r r o w cone, t h e w i d t h of wh ich is r e la ted to t he size of the in te rac t ing system. At t he GeV energies so far explored (up to about 8 GeV c.m.s.) a r a t h e r smal l p a r t of p - p sca t te r ing appea r s to be caused by a poten t ia l or bi l l iard bal l t ype of behaviour .

T h e physical in te res t in p - p sca t te r ing lies in t h e deta i led shape of this fo rward diffraction peak, i ts va r ia t ion w i t h energy, a n d the w a y in wh ich t h e potent ia l type of elastic sca t te r ing changes w i t h energy. Observa t ions of p - p sca t te r ing a t CERN in 1961-62 showed a ve ry charac te r i s t ic fea ture of t he diffraction peak, name ly t h a t its w i d t h decreased w i t h increas ing energy. The ' sh r ink ing ' of t he diffraction peak s t imu­la ted g rea t in te res t bo th theore t ica l ly (Regge poles) and expe r imen ta l ly (many elastic sca t ter ing expe r imen t s subsequent ly done) and the ISR offers t he possibil i ty to exp lore the p h e n o m e n o n to ex t r eme ly h igh energies .

The poten t ia l type of sca t te r ing is s tudied by m e a s u r ­ing its in te r fe rence w i t h Coulomb scat ter ing. This is possible only a t ve ry smal l angles w h e r e Coulomb sca t te r ing is s t rong. T h e angles of in teres t even a t t h e ve ry h igh energy of t h e ISR a re still qu i te reasonab le from the e x p e r i m e n t a l poin t of view. It is in fact one of t he mer i t s of t he s t a t ionary cent re of mass sys tem t h a t t h e in te res t ing a n g u l a r r a n g e is not res t r ic ted to impossibly smal l angles as would be t he case for a convent ional s t a t iona ry t a rge t expe r imen t a t equ iva len t cen t re of mass energy.

Hav ing m e a s u r e d p - p sca t te r ing a t h igh energies , one is a lways in te res ted to compare the behav iour w i t h t h a t of the p r o t o n - n e u t r o n system. This should be possible w i t h t he ISR prov ided t ha t deu te rons can be accelera ted in t h e P S a n d t r ans fe r red to t he ISR. F r o m the expe r imen t s it should be possible to deduce t h e

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b e h a v i o u r of t he p - n in te rac t ion a s suming t h a t t he p - p in te rac t ion is known.

T h e elastic sca t te r ing m e a s u r e m e n t s would use severa l k inds of detectors . For t he ve ry smal les t angles , in t he Coulomb in te r fe rence region, mat r i ces of solid s ta te detectors inside t h e v a c u u m c h a m b e r of t he m a c h i n e would be conceivable . For r a t h e r l a rge r angles , t he s tudy of t he shape of t he diffraction peak, w i r e spa rk chamber s wou ld seem to offer the bes t possibi l i ty w i th respect to precis ion of par t ic le location a n d speed of operat ion. A n a r r a y of bo th k inds of de tec tors connected on l ine to a compu te r should a l low t h e m e a s u r e m e n t of t he comple te elast ic sca t te r ing a n g u l a r d is t r ibut ion up to t r a n s v e r s e m o m e n t a of abou t 1 GeV/c.

T h e to ta l p - p and p - n cross-sect ions could, in p r i n ­ciple, be deduced from the m e a s u r e d smal l -ang le sca t ­t e r ing us ing a genera l q u a n t u m mechan ica l t h e o r e m cal led t h e optical theorem. However , th is wou ld still en ta i l some assumpt ions , a n d subs id ia ry scint i l lat ion coun te r expe r imen t s observ ing the loss of par t ic les f rom the in te rac t ion region would give di rect m e a s u r e ­m e n t s of t he total cross-sect ions. T h e energy va r ia t ion of t he p - p and p - n to ta l cross-sect ion is of fundamen ta l in te res t in connect ion w i t h some genera l c u r r e n t t h e o r e m s about t he asympto t ic n a t u r e of s t rong i n t e r ­act ions .

2. Particle Spectroscopy

When two pro tons collide t hey m a y shake each o the r so violent ly t h a t n e w par t ic les a r e l ibera ted from them. This phenomenon is called par t i c le product ion . All t h e k n o w n sub-nuc lea r par t ic les w h i c h can feel s t rong in te rac t ion forces m a y be c rea ted in th is way . One m a y t h ink of this process as t h e s t r ipp ing off of p a r t of a cloud from t h e pro tons . L igh t par t ic les , t h e j t -mesons , a re r a t h e r easy to shake off; energies of a r o u n d 140 MeV a re sufficient. They a r e t he con­s t i tuen ts of the r i m of t h e cloud. O the r par t ic les a r e p roduced in pai rs , for e x a m p l e K-mesons and a n t i -K-mesons plus hyperons . If t he collision energy is ra ised higher , pa i r s of nucleons, for ins tance a p ro ton p lus an ant ipro ton , can also be produced . Such a pa i r of par t ic les is ve ry heavy, and a n ava i lab le energy of 2 GeV is r equ i red to c rea te t hem. They come from t h e v e r y h e a r t of the cloud.

This phenomenon of pa r t i c le p roduc t ion is t h e n in t imate ly connected w i t h t he s t ruc tu r e of the p ro ton a n d observat ions of the par t ic les wh ich a r e c rea ted in such collisions, of the i r r e la t ive a b u n d a n c e and energy, the i r angu la r d is t r ibut ion a n d the i r possible corre la t ions w i t h each other , gives us some informat ion about t h e a r r a n g e m e n t and dynamics of th is cloud wh ich cons t i ­tu tes the s table proton.

Eve ry t ime a n e w energy r a n g e has opened up for par t ic le physics, one of t he first th ings to be inves t iga ted has been the p roduc t ion of par t ic les . This has been done a t t he 28 GeV CERN P S and a t t he 33 GeV Brookhaven A G S and t h e overa l l p a t t e r n observed a t these energies can be d r a w n qu i te s imply : as a p ro ton is shaken more and more violent ly, increas ing n u m b e r s of j t-mesons a r e s t r ipped off. One could h a v e imagined t h a t ins tead of more and m o r e ; t-mesons, fewer heav ie r

par t ic les could be created. This is not found a t cu r ­ren t ly ava i lab le energies . The colliding pro tons r a t h e r sepa ra te off a n d fly a w a y w i t h the i r clouds exci ted to h igher energy a n d finally r e t u r n to the i r no rma l s ta te by emi t t ing some j t-mesons. I n such collisions ve ry l i t t le of t he ava i lab le ene rgy goes into par t ic le p r o ­duction. Somet imes , however , two colliding pro tons sha re t h e who le energy of t he collision and form for a brief t ime someth ing l ike a v e r y hot droplet . T h e n heavy par t ic les a r e c rea ted also and boil off from the droplet .

The p ic tu re wh ich has been d r a w n he re has in fact been der ived from observa t ions of t h e s table par t ic les wh ich surv ive long enough to b e detected. T h e m a i n key to this is a spectroscopy of t h e f requency of p a r ­ticles of different mass . I t is going to be ve ry in t e r ­est ing to c a r r y this s tudy to t h e h igher energies avai lable a t t he ISR.

3. A Weak Interaction Experiment

The expe r imen t s so far discussed h a v e been concerned w i th s t rong in terac t ions . T h e l a rge energy avai lable at the ISR suggests a search for an elusive object called the i n t e rmed ia t e vec tor boson, W, supposedly the ca r r ie r par t ic le , or field, of t h e w e a k interact ions . High energy neu t r ino e x p e r i m e n t s a t CERN and Brook-haven h a v e searched for th is object w i thou t success and the i r nega t ive resu l t s suggest tha t , if t he boson exists a t all, i ts mass is g rea t e r t h a n about 1.9 GeV.

An in te res t ing p r o p e r t y of t h e hypothe t ica l W is t h a t its s t r eng th of in te rac t ion depends on its mass . Hence, if bosons do exis t w i t h ve ry h igh mass they might wel l become read i ly observab le p rov ided enough energy is avai lable to p roduce them.

A possibili ty, then, is to search for W p roduct ion in p ro ton -p ro ton collisions w i t h energies up to 56 GeV c.m.s. a t t he ISR. T h e me thod of detect ion of the W rel ies on observing its decay into a m u o n and a neu t r ino . Muons ar i s ing from t h e decay of pions and kaons t end to emerge from t h e in te rac t ion region a t smal l angles, following t h e t ra jec tor ies of the i r p a r e n t par t ic les which , as w e r e m a r k e d earl ier , have smal l t r ansve r se momen ta . T h e decay of a ve ry massive, slowly moving par t ic le , l ike t h e W, could give, however , muons emerg ing w i t h h igh m o m e n t a a t r a t h e r la rge angles and t h e e x p e r i m e n t wou ld re ly on th is to sepa ra te t he W decay muons f rom the rest .

The e x p e r i m e n t wou ld use scint i l la t ion counters and spa rk c h a m b e r s to look for m u o n s of h igh t r ansve r se m o m e n t a pene t r a t i ng a th ick shie lding wa l l a round the ISR in te rac t ion region. Yields of w ide angle muons s tudied as a funct ion of inc ident m o m e n t u m could then give some h in t as to w h e t h e r or not the W exists .

The Experimental Conditions

At the p resen t accelera tors , de tec tors have been used to m a k e m e a s u r e m e n t s a t different angles a round a t a rge t wh ich is b o m b a r d e d w i t h protons . A b e a m of accelera ted pro tons is b r o u g h t to one of the expe r i ­men ta l ha l l s and d i rec ted onto a t a rge t of l iquid hydrogen. In this s i tuat ion, t he detect ion equ ipmen t could be pu t even a t 0°, a region w h i c h for an in te rna l t a rge t is obs t ruc ted b y the acce le ra tor magne t uni ts .

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The energy of t h e resu l t ing par t ic les is selected by a magne t i c field, and par t ic les of different mass have different velocit ies w h i c h can be m e a s u r e d by Cerenkov counters or s imply b y the i r t ime of flight.

At t he ISR the s i tua t ion is qu i te different a n d more complicated. One b e a m is t h e t a rge t of the o the r and the collisions to be s tudied occur inside a v a c u u m vessel. Special care has been t a k e n to p rov ide enough free space be tween t h e m a g n e t un i t s a t t he 8 i n t e r ­section points of t he two beams . Bu t t he immedia te ly fo rward direct ion is not accessible for magne t i c fields wh ich could sweep par t ic les out, since this wou ld also d i s tu rb the c i rcula t ing pro tons .

The p ro ton b e a m s also collide w i t h t he gas wh ich is left in the v a c u u m vessel. Even a t 1 0 - 1 1 t o r r t he gas dens i ty (the n u m b e r of a toms pe r cm 3 ) is comparab le w i t h the dens i ty of t he t a rge t beam. Moreover t he b e a m s cross over a l eng th of some 20 cm, wh i l e t he gas is p resen t all a r o u n d the r ings .

How a re w e to d is t inguish a par t ic le c rea ted in a b e a m - b e a m collision from those m a d e in b e a m - g a s collisions ? T h e r e a r e severa l possibili t ies. We can use a detector w h i c h can 'see' only t h e region of b e a m -b e a m interact ion, or w e can record t h e t r acks of p a r ­ticles in spa rk c h a m b e r s a n d recons t ruc t the i r origin f rom the s p a r k c h a m b e r read ings . Also, condit ions can be imposed on t h e par t ic les to be recorded so t h a t the i r energies add u p to va lues wh ich a re impossible f rom b e a m - g a s collisions. T h e detect ion a p p a r a t u s could then, in pr inciple , be qui te s imi lar to t he ones used a t p resen t acce lera tors . Of course it ha s to cover a m u c h wide r r a n g e of angles , because t he colliding p ro tons a r e not pushed into one common direct ion as in t he case w i t h t a rge t s a t rest .

Fo rmidab le de tec tors wil l h a v e to be bui l t to cover t h e whole angu la r region a r o u n d t h e b e a m crossing points . Angles a n d energies of all par t ic les h a v e to be de t e rmined and also the i r mass . These detec tors wil l g row to" t he size of our biggest bubb le c h a m b e r s and yet, as opposed to the b u b b l e chambers , t hey h a v e to select in some w a y the ' in teres t ing ' events . Most p robab ly t hey wil l be a combina t ion of w i r e - s p a r k chamber s and magne t i c fields us ing a compu te r on- l ine to select and record the events .

W h a t can w e expec t to find in this n e w energy r a n g e ? Is t h e r e a n y t h i n g w e could an t ic ipa te or imagine ? Can a look a t t h e da t a from cosmic r a y expe r imen t s he lp us ? If t h e diffraction p a t t e r n in elast ic sca t te r ing cont inues to shr ink, as discussed above, th is could h a v e its or igin in some changes in t h e p roduc t ion phenomena . Some uns tab le par t ic le clusters , guessed a t f rom cosmic r a y expe r imen t s and chr i s tened 'fireballs ' , could be effective in p roduc ing par t i c le ' je ts ' in a charac ter i s t ic way .

One of t h e s imples t in te rac t ions involving uns tab le s ta tes is t h e process p + p -> p + N* w h e r e N* is an exci ted nucleon. This has been s tudied qu i te e x t e n ­sively a t CERN a n d B r o o k h a v e n w i t h r a t h e r s imple expe r imen t s de tec t ing t h e inelast ical ly sca t te red pro ton only. F r o m m e a s u r e m e n t s of t h e m o m e n t u m and direct ion of t he proton, conserva t ion of ene rgy al lows us to deduce t he mass of t h e unobse rved N* (this has

a l i fet ime for decay into a nucleon and pion of abou t 10~2 3 s). Wi th t h e ISR, s imple detect ion of t he s ingle sca t te red pro ton is p robab ly not enough as its m o m e n ­t u m difference f rom elast ical ly sca t te red pro tons is ve ry smal l (about 20 MeV/c). Hence some informat ion on the decay of t he uns t ab l e s ta te is needed. T h e process t h e n appea r s in t h e s implest class of je t even t s in wh ich a ve ry h igh energy p ro ton is detected in coin­cidence w i t h a r a t h e r s imple je t configurat ion (Njt or NJTJT for example) .

The e x p e r i m e n t a l p r o g r a m m e on this type of reac t ion wou ld a im to s tudy the ene rgy and angle dependence of t he cross-sect ion for p roduc ing the var ious N * s ta tes . T h e detai ls of these var ia t ions a r e of in teres t as t hey m a y be expec ted to depend on the q u a n t u m n u m b e r s of the s tates . More specifically, it is expec ted from cer ta in genera l ideas of s t rong in teract ions , t ha t those N * s ta tes w i t h q u a n t u m n u m b e r s differing least f rom those of t he nuc leon wi l l be exci ted most s t rongly. This idea is of cons iderable impor t ance and it is necessary to test it a t t he h ighes t energies.

In t h e p roduc t ion of s tab le par t ic les t he r e migh t b e n e w phenomena . The produc t ion of t he ' cheap ' jx-mesons m a y no longer d a m p so s t rongly the p r o d u c ­t ion of m o r e mass ive s ta tes such as nucleon pa i r s . Also new, as yet u n k n o w n , m o r e mass ive par t ic les m a y be produced.

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France Hewlett-Packard France Paris 13e, Tel. 707.97.19

Germany Hewlett-Packard Vertriebs-G.m.b.H. Frankfurt a.M., Tel . 52.00.36

Holland Hewlett-Packard Benelux, N.V. Amsterdam-Z, Tel. 42 77 77

Italy Hewlett-Packard Italiana S.p.A. Milan, Tel . 69.15.84/5/6

Rome-Eur, Tel. 591.25.44-5

Sweden HP Instrument AB Solna, Tel . 83.08.30 Goteborg, Tel . 27.68.00

143

OUR SOLUTION FOR YOUR PROBLEM LIQUID SCINTILLATORS

NE 5560 Liquid Scintillation Tank of 500 litre capacity completed for France

NE 8307 Liquid Scintillation Spectrometer

We provide the g r e a t e s t v a r i e t y of scintillator solutions available today. For o v e r a d e c a d e scientists throughout the world have chosen Nuclear Enterprises scintillators to solve their radiation counting problems. The range is being continually improved and extended.

For N u c l e a r R e s e a r c h For B i o l o g i c a l & M e d i c a l I n v e s t i g a t i o n s The versatil ity of l iquid scinti l lators provides an excellent means of approaching many problems in nuclear research.

NE 2 1 1 : Standard l iquid scintil lator. NE 224: High flash point, very high l ight

ou tput (80% Anthracene), and excellent l ight transmission.

NE 213: For fast neutron detection in the presence of gamma radiation using pulse shape d iscr imin ­a t ion techn iques .

NE 223: Decalin based, for use in Perspex ce l ls .

NE 228: High hydrogen content for neut ron studies.

NE 226: "Hydrogen- f ree" ; insensi t ive t o n e u t r o n s .

Loaded NE 313 and 3 2 3 : Gadol inium Liquids: loaded for n e u t r o n spec t ro ­

m e t r y . NE 3 1 1 , 311A and 321 A: Boron loaded for n e u t r o n d e t e c t i o n . NE 318 : L i t h i u m loaded for neutron detect ion. Cd, Pb, Sn, Sm. Si and In loaded scintil lators also available.

To meet the rapidly growing demands of biologists, health physicists, and chemists in the field of in terna l count ing we offer a comprehensive range of scintil lators to use w i t h Automat ic Sample Counters and Manual Spectrometers. (See i l lustration).

NE 240: A n e w dioxane based scintil lator for aqueous samples w i th t w i c e t h e capaci ty f o r w a t e r compared w i t h N E 220. It accepts 20% of an aqueous sample and has an improved l ight output (67% Anthracene).

N E 2 1 4 : A n e w xylene based scintil lator w i th improved l ight output ( 8 2 % Anthracene).

NE 213: Standard l iquid scintil lator w i th a xylene base for general internal count ing applications.

NE 220: Liquid scintil lator w i th dioxane base for incorporation of aqueous samples.

NE 2 2 1 : Gel scintil lator for suspending insoluble samples or incorporating aqueous suspensions.

NE 215: This scintil lator based on monoisopropylbiphenyl is non-volat i le, and has proved valuable for count ing of material on filter paper.

For S p e c i a l N e e d s Scintil lators can be supplied to meet very special requirements, either unloaded or loaded w i th such metals as Bi, Eu, Ho, La, Pr etc.

Full details of all scintil lators and associated electronic equipment available on request.

N U C L E A R E N T E R P R I S E S (G .B . ) L T D . Sighthill, EDINBURGH 11, Scotland. Tel: CRAiglockhart 4060. Cables: 'Nuclear Edinburgh9

Canadian Associate : Nuclear Enterprises Ltd., 550 Berry Street, Winnipeg 21. U.S. Representative: Nuclear Enterprises Division, h-nu systems inc., 470 San Antonio Road, Palo A l to , California.

144

ADJUSTABLE DELAY LINE

TWIN DELAY LINE TYPE 701 offers:

— Two independent delay circuits

— Digital delay selection

— Single steps of 1 ns

— Maximum adjustable delay 99 ns

— Negligible damping

— Reflection loss smaller than 5 %

— Remote Control

Other products :

FAST SCALER types 601-613, resolution corresponding to 2,20 or 100 Mc/s, 6 or 8 decades per scaler, binary or decimal display, built in power supply and automatic readout faci l i t ies.

READOUT LOGIC 630 Control unit for automatic readout up to 98, 6 or 8 decades - scalers.

DRIVE UNIT 642 Simultaneous control of recording instruments such as output writers, tape perforators etc.

PARAMETER UNIT 650 For insertion of ident i f icat ion and information to be read out together with the scaler contents.

OUTPUT WRITER 494 with typing head. Operates at an output speed of 14 characters/s.

HIGH SPEED TAPE PUNCH 493 for 110 characters/s, self contained power supply.

T A P E R E A D E R 495 f o r 10 c h a r a c t e r s / s .

Wr i te or phone for more details.

I ELECTRONIC S O L O T H U R N CD©rer C© ~ S W I T Z E R L A N D Heidenhubelstr. 24 Tel . 065 / 2 85 45

Great Britain: 36, East Street, Shoreham-by-Sea, Sussex, te l . 4305

Germany : Kaiserstrasse 10, 8 Munchen 23 France : Sorel ia Electronique, 92 Courbevoie, 25, rue de Nor-

mandie, te l . 333 82-96

Italy : D.I.S.I. Nuclear Corporat ion, Viale Lunigiana 40, Milano

145

NEW PRODUCTS FROM...

FROM 1 r s t OF APRIL 1966

100 Mc COUNTER, DECIMAL VERSION-SEN 136 - Size and readout circuits compat ib le with standard SEN

123 scaler (CERN 3009) - Frequency range: zero DC to over 100 Mc (countinuous

and aperiodic rates) - Better than 10 ns tr iple pulse resolut ion - Minimum input pulse w id th : 2 ns - Input impedence: 50 or 75 Ohms - Adjustable input threshold from 350 mV to 1,5 Volt - Input circuit protected against overloads - Capaci ty: 10 6

100 Mc COUNTER, BINARY VERSION-SEN 194 - Same general character ist ics as the SEN 1 7 6 counter - Straight binary output for efficient operation with "on line' 1

computers - Capaci ty : 2 n

BUFFER MEMORY-, SEN 400 - Allows recording of several events during each burst of

accelerators - Provides most efficient use and considerable economy of

magnetic tape - Capaci ty : 1024 words of 24 bits - Compatible with SEN standard counting systems - Standard chassis for 19" rack NEW LINE OF MEMORY MODULES SOLVING SPECIFIC NEEDS OF PHYSICISTS.

SOCIETE D'ELECTRONIQUE NUCLEAIRE 31 ,AV .ERNEST-P ICTET GENEVE-SUISSE TEL. ( 0 2 2 ) 4 4 2 9 4 0

NEW ADDRESS

31, av. Ernest-Pictet Geneva Switzerland

New Vac Ion Pumps

varian

Here are the new Vaclon® Pumps wi th speeds of 140 l/s, 270 l/s, 500 l/s and 1000 l/s. The new control units start these pumps twice as fast as older pumps and del iver more power for faster pumping at high pressure. The large diameter anode cells and new magnets, wh ich are bakeable to 400 °C, provide more speed at low pressures and faster bakeout cycles. Please contact Varian AG, Baarerstrasse 77, 6300 Zug, Switzer land, Tel . (042) 4 45 55 for data sheet Vac 2227 descr ib ing the new pumps.

High VACUUM Components immedia te ly avai lable f rom Zur i ch s tock

Precision electr ic

Ovens and Furnaces

Heat ing and dry ing ovens, incubators , tube fu rnaces

QUARTZ Tubes made of Hera lux f rom our Zur ich s tock. A r t i c les for Labora to r ies and op t i cs made of quartz

Sole agency for Swi tzer land and L iechtens te in

Wismer AG Oerl ikonerstrasse 88 8057 Zurich Te l . 051 46 40 40

Heraetu

Two new modules further increase capability of EG&G's M100 system.

NEW T101 DISCRIMINATOR/TRIGGER HAS 1 0 0 % DUTY FACTOR OPERATION This unique new unit eliminates deadtime so you can (1) achieve noise rejection on veto (anti-coincidence) channel without compromising 100% efficiency (only limitation is detector resolution) and (2) have no multiple-pulsing on long inputs. If you wish 50% duty factor, it takes only the flick of a switch. Of course, the new T101 provides the same accurate, stable, continuously-variable threshold that helped make our T100A Discriminator so popular.

NEW TD101 DIFFERENTIAL DISCRIMINATOR (SINGLE-CHANNEL PULSE-HEIGHT ANALYZER) For the first time you can have a fast

"single-channel analyzer" function available in one module at lower cost. The TD101 can also be used as a complete f fslow-fast" logic channel at a flick of a switch. The TD101 has accurate, stable, con­tinuously-variable thresholds and the same 100% Duty Factor capability as the new T101. Illustrated application notes and specifications on these two new modules, as well as the other 25 in the Ml00 Counting System are available. Write: EG&cG, Inc., Salem Laboratory, 35 Congress Street, Salem, Massachusetts 01970. Phone: (617) 745-3200. Field offices: Chicago, 111., Phone: (312) 237-8565; Palo Alto, Cal., Phone: (415) 327-8328. Representatives in foreign countries.