ISPRA Nuclear Electronics Symposium EUR 4289

Europäische Atomgemeinschaft

Communauté Européenne de l'Energie Atomique

Comunità Europea dell'Energia Atomica

Europese Gemeenschap voor Atoomenergie

European Atomic Energy Community

E U R A T O M

. Sitzungsberichte Actes officiels

Atti ufficiali Handelingen

Proceedings

ISPRA NUCLEAR ELECTRONICS SYMPOSIUM

6-9.5.1969

1969

Veröffentlich von der Kommission der Europäischen Gemeinschaften Generaldirektion Verbreitung

der Kenntnisse

Zentralstelle für Information und Dokumentation - CID Pubblicato dalla Commissione della Comunità Europee Direzione generale

Diffusione delle Conoscenze Centro d'Informazione e di Documentazione - C.I.D.

Publié par la Commission des Communautés Européennes Direction générale

Diffusion des Connaissances Centre d'Information et de Documentation - C.I.D.

Gepubliceerd door de Commissie van de Europese Gemeenschappen Directoraat-generaal

Verspreiding van Kennis Centrum voor Informatie en Documentatie - CID Published by the Commission of the European Communities

Directorate-General for Dissemination of Information Centre for Information and Documentation - CID

ISPRA NUCLEAR ELECTRONICS SYMPOSIUM

Organisiert unter

Forderung von

Organisé sous

les auspices de

OrganÏ2zato

sotto gli auspici di

Opgesteld onder

auspiciën van

Orgaiúzed under the

sponsorship of

IEEE

North Italy Section

IEEE

Nuclear Science Group

CNR

Consiglio Nazionale delle Ricerche

CNEN

Consiglio Nazionale per l'Energia

Nucleare

ΑΕΙ

Associazione Elettrotecnica ed

Elettronica Italiana

SIF

Società Italiana di Fisica

Ausschuß für die Auswahl der Artikel

Comité de Sélection des Articles

Comitato di Selezione degli Articoli

Keuzecomité van de Artikelen

Paper Selection Committee

E. Gatti, Chairman — E. Baldinger —

B. Soucek and L. Stanchi.

R.L. Chase — K. Kandiah — J. Pottier —

LEGAL NOTICE

The Commission of the European Communities

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information

Price DM 48

Lit. 7 500

FB 600

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FF 60

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12

Foreword

High level scientists and engineers met at Stresa to attend the Ispra Nuclear Electronics Symposium. This International Sympo­ sium was organized by the Euratom Joint Nuclear .Research Center of Ispra and sponsored by the Institute of Electrical and Electronics Engineers (North Italy Section and Nuclear Science Group). Co­spon­ sors were four Italian Institutes: CNß (Consiglio Nazionale delle Ricerche), CNEN (Comitato Nazionale per l'Energia Nucleare), ΑΕΙ (Associazione Elettrotecnica ed Elettronica Italiana), SIF (Socie­ tà Italiana di Fisica).

Outstanding papers were presented and I wish to thank all the authors for their contributions. The complete manuscripts of three among the papers announced, were not presented for various .reasons. I would apologize to the reader for the fact that he has found only summaries. The accepted papers were carefully selected by an inter­ national committee and I think that the choice was well made indeed. Naturally the choice based on summaries can lead to improper results and perhaps some rejected paper deserved better attention. In addi­ tion several papers arrived after the selection was made and had no possibility to be accepted. There are some minor variations in the program due to the fact that some people invited, only sent their acceptance after the program had been printed.

The Symposium had originally been planned to last for three days, but it became opportune to add a fourth day to the program, in order to deal with the subject of modular instrumentation with par­ ticular emphasis on the new CAMAC standard. From this the title of the CAMAC­day was derived. A panel discussion on future trends had already been scheduled for that same day at Ispra. I must therefore once more apologize for some misunderstanding caused by this, and explain that the panel discussion was quite independent of the Sym­ posium. This latter ran up to the fourth day as foreseen by thè pro­ gram.

I wish to thank all the people who contributed to the organiza­ tion as well as the many participants who wished amiably to congra­ tulate me on the success of the Symposium.

L. STANCHI

Préface

Des savantB et ingénieurs hautement q u a l i f i é s se r e t r o u v a i e n t à Stresa pour p a r t i c i p e r au Congrès "Ispra Nuclear Electronios Sym­ posium". Cette manifestation é t a i t organisée par l e Centre Commun de Recherche Nucléaire de I s p r a sous l ' é g i d e par 1'IEEE(lnstitute of E l e c t r i c a l and E l e c t r o n i c s Engineers) et ses deux sections (North

\ W l l l l l , a i U . « a i i l U I l O l C ¿ ( O l J. JJi I l· J. £, J. u. H U ^ L U Ì L ; , " « ^ y « w w w v ^ . u u ^ . v 4 i w

K L e t t r o t e o n i o a ed E l e t t r o n i c a I t a l i a n a ) , SIF ( S o c i e t à I t a l i a n a d i F i s i c a ) .

Des Communications de g r a n d i n t é r ê t é t a i e n t p r é s e n t é e s e t j e d é s i r e en r e m e r c i e r t o u s l e s a u t e u r s . P o u r d i f f é r e n t e s r a i s o n s t r o i s m a n u s c r i t s p r é v u s au programme n ' é t a i e n t p a s p r é s e n t é s ¡ a u s s i j e p r i e l e l e c t e u r de m ' e x c u s e r s ' i l n ' e n t r o u v e que l e s r é s u m é s .

Les a r t i c l e s f u r e n t s o i g n e u s e m e n t s é l e c t i o n n é s p a r un c o m i t é i n t e r n a ­ t i o n a l e t j e p e n s e que l e c h o i x f u t r é e l l e m e n t j u d i c i e u x . Evidemment, é t a n t b a s é s u r d e s r é s u m é s , i l a u r a pu ê t r e un peu a r b i t r a i r e e t d e s a r t i c l e s r e j e t é s a u r a i e n t s a n s d o u t e m é r i t é d ' ê t r e mieux c o n s i d é r é s . P a r a i l l e u r s p l u s i e u r s r e s u m é s s o n t a r r i v é s en r e t a r d e t n ' o n t pu m a l ­ h e u r e u s e m e n t ê t r e a c c e p t e s . Q u e l q u e s i n v i t é s a y a n t r é p o n d u a f f i r m a ­ t i v e m e n t s e u l e m e n t a p r è s l ' i m p r e s s i o n du programme, i l y e u t q u e l q u e s m o d i f i c a t i o n s dans son o r d o n n a n c e m e n t .

Le Symposium é t a i t p r é v u à l ' o r i g i n e p o u r t r o i s j o u r s , m a i s i l p a r u t o p p o r t u n de l e p r o l o n g e r d ' u n e j o u r n é e p o u r t r a i t e r l e problème de l a s t a n d a r d i s a t i o n d e s a p p a r e i l l a g e s e t t o u t p a r t i c u l i è r e m e n t du s y s t è m e m o d u l a i r e CAMAC. C ' e s t a i n s i que n a q u i t l e "CAMAC­day". Une t a b l e r o n d e s u r l e s p e r s p e c t i v e s f u t u r e s a v a i t d é j à é t é o r g a n i s é e à I s p r a p o u r l e même j o u r . J e v o u d r a i s m ' e x c u s e r e n c o r e une f o i s p o u r l e s q u e l q u e s m a l e n t e n d u s q u i o n t s u r g i à ce p r o p o s e t s o u l i g n e r que c o t t e t a b l o r o n d e é t a i t i n d é p e n d a n t e du c o n g r è s l u i ­ m ê m e , q u i s ' e s t p o u r s u i v i j u s q u ' a u q u a t r i è m e j o u r comme p r é v u .

J e d é s i r e r e m e r c i e r t o u t e s l e s p e r s o n n e s q u i o n t p a r t i c i p é à l ' o r g a n i s a t i o n de ce c o n g r è s a i n s i que l e s p a r t i c i p a n t s q u i o n t eu l ' o b l i g e a n c e de me f é l i c i t e r p o u r l e s u c c è s de ce Symposium.

L. STANCHI

Vorwort

Im Mai 1969 fand i n S t r e s a das " I s p r a Nuclear E l e c t r o n i c s Symposium" B t a t t , zu dem s i c h nahmhaftë und q u a l i f i z i e r t e Wissen­ s c h a f t l e r und I n g e n i e u r e zusammenfanden. O r g a n i s a t o r des T r e f f e n s war das Forschungszentrum l e p r a der Europäischen Atomgemeinschaft und das I n s t i t u t e of E l e c t r i c a l and E l e c t r o n i c s Engineers (North I t a l y Section and Nuclear Science Group) u n t e r Patenschaft, von v i e r i t a l i e n i s c h e n I n s t i t u t e n : CNH (Consiglio Nazionale d e l l e R i c e r c h e ) , CNEN (Comitato Nazionale per l ' E n e r g i a N u c l e a r e ) , ΑΕΙ ( A s s o c i a ­ zione E l e t t r o t e c n i c a ed E l e t t r o n i c a I t a l i a n a ) , SIF ( S o c i e t à I t a l i a ­ na di F i s i c a ) .

Ich möchte a l l e n Referenten und Autoren für i h r e B e i t r a g e dan­ ken. Alle p r ä s e n t i e r t e n Manuskripte s i n d im Nachfolgenden abge­ d r u c k t . A l l e r d i n g s fehlen ­ aus u n t e r s c h i e d l i c h e n Gründen ­ d r e i der angekündigten R e f e r a t e . Ich bedauere sehr den Umstand, dass von ihnen nur Zusammenfassungen gegeben werden können.

Die g e h a l t e n e n Referate bzw. v e r ö f f e n t l i c h t e n Manuskripte wur­ den s o r g f ä l t i g von einem i n t e r n a t i o n a l e n Programraausschuss a u s g e ­ wählt und i c h g l a u b e , dass d i e Auswahl gut war. Es i s t a l l e r d i n g s möglich, daas angebotene B e i t r ä g e zu Unrecht zurückgewiesen wurden, da a l s B e u r t e i l u n g s g r u n d l a g e nur j e w e i l s d i e Zusammenfassung des R e f e r a t e s d i e n t e . Eine Reihe von Beiträgen mu3ste zurückgewiesen werden, da s i e zu spät ­ e r s t naoh Beginn der Auswahlprozedur ­ e i n t r a f e n .

Ursprünglich war das Symposium für e i n e Dauer von d r e i Tagen g e p l a n t . Es wurde aber dann ein v i e r t e r Tag hinzugenommen, der der Information und den Problemen von F u n k t i o n s ­ und Baugruppen e l e k ­ t r o n i s c h e r I n s t r u m e n t i e r u n g e n (modular i n s t r u m e n t a t i o n ) gewidmet war. Besonderer Nachdruck wurde h i e r b e i auf das neue CAMAC­System g e l e g t , weshalb d i e s e r Tag auch a l s CAMAC­day bezeichnet wurde. Eine P a n e l d i s k u s s i o n über zukünftige Entwicklungsrichtungen war am g l e i c h e n Tag in I s p r a vorgesehen. Ich möchte mioh noch einmal e n t s c h u l d i g e n für e i n i g e M i e s v e r s t ä n d n i s s e , die d i e s e r Umstand v e r u r s a c h t e j d i e s e Diskussion war v ö l l i g unabhängig vom Symposium, das am v i e r t e n Tag wie im Programm vorgesehen a b l i e f .

loh möchte a l l e n denen danken, d i e d i e O r g a n i s a t i o n des Tref­ fens b e s o r g t e n , sowie auch den v i e l e n Teilnehmern, die mich freund­ l i c h e r w e i s e zum Erfolg des Symposiums beglückwünschten.

L. STANCHI

P r e f a z i o n e

S c i e n z i a t i e t e c n i c i d i a l t o l i v e l l o c o n v e n n e r o a S t r e s a p e r p a r t e c i p a r e a l Congresso " I s p r a N u c l e a r E l e c t r o n i c s Symposium". Questo c o n g r e s s o i n t e r n a z i o n a l e o r g a n i z z a t o d a l C e n t r ò Comune di R i c e r o h e N u c l e a r i d i I s p r a e r a p a t r o c i n a t o d a l 1 ' I E E E ( I n s t i ­ t u t e of E l e c t r i c a l and E l e c t r o n i c s E n g i n e e r s ) con l e sue due r a m i f i c a z i o n i : l a s e z i o n e Nord I t a l i a e i l g r u p p o " N u c l e a r S c i e n c e " . P a t r o c i n a t o r i a s s o c i a t i e r a n o q u a t t r o i s t i t u z i o n i i t a ­ l i a n e : CNR ( C o n s i g l i o N a z i o n a l e d e l l e R i c e r c h e ) , CNEN ( C o m i t a t o N a z i o n a l e p e r l ' E n e r g i a N u c l e a r e ) , ΑΕΙ ( A s s o c i a z i o n e E l e t t r o t e c ­ n i c a e d E l e t t r o n i c a I t a l i a n a ) , SIF ( S o c i e t à I t a l i a n a d i F i s i c a ) .

A r t i c o l i d i e l e v a t o v a l o r e sono s t a t i p r e s e n t a t i e d i o d e s i d e r o p e r t a n t o r i n g r a z i a r e t u t t i g l i a u t o r i p e r l e l o r o c o n t r i b u z i o n i . I m a n o s c r i t t i c o m p l e t i d i t r e f r a g l i a r t i c o l i a n n u n c i a t i non s o ­ no s t a t i p r e s e n t a t i p e r d i f f e r e n t i r a g i o n i . V o r r e i s c u s a r m i o o l l e t t o r e p e r i l f a t t o che t r o v e r à s o l o i r i a s s u n t i . Gli a r t i c o l i a o c e t t a t i f u r o n o s e l e z i o n a t i a c c u r a t a m e n t e da un c o m i t a t o i n t e r ­ n a z i o n a l e . Ed i o penso che l a s c e l t a f u ' f a t t a i n e f f e t t i m o l t o b e n e . N a t u r a l m e n t e , l a s c e l t a b a s a t a su sommari, può p o r t a r e a r i s u l t a t i i m p e r f e t t i e f o r s e q u a l c h e a r t i c o l o r e s p i n t o m e r i t a v a u n a m i g l i o r e a t t e n z i o n e . I n o l t r e p a r e c c h i a r t i c o l i p e r v e n n e r o dopo l a s e l e z i o n e e non e b b e r o l a p o s s i b i l i t à d i e s s e r e a o c e t t a t i .

I l c o n g r e s s o e r a s t a t o p r e v i s t o o r i g i n a r i a m e n t e p e r t r e g i o r n i ma s i t r o v ò o p p o r t u n o a g g i u n g e r e un q u a r t o g i o r n o a l programma, d e d i c a t o a l l a s t r u m e n t a z i o n e m o d u l a r e con p a r t i c o l a r e e n f a s i a l nuovo s t a n d a r d CAMAC. Da c i ò fu d e r i v a t o i l t i t o l o "CAMAC­day". Una d i s c u s s i o n e a d i n v i t o s u l l e t e n d e n z e f u t u r e e r a s t a t a g i à programmata p e r q u e s t o s t e s s o g i o r n o a I s p r a . V o r r e i a n c o r a s c u ­ s a r m i p e r q u a l c h e i n c o m p r e n s i o n e c a u s a t a da q u e s t o m o t i v o e s p i e ­ g a r e che l a d i s c u s s i o n e e r a i n d i p e n d e n t e d a l c o n g r e s s o . Q u e s t ' u l ­ timo h a p r o c e d u t o s i n o a l q u a r t o g i o r n o come< p r e v i s t o d a l p r o g r a m ­ ma.

V o r r e i r i n g r a z i a r e t u t t e l e p e r s o n e che c o n t r i b u i r o n o a l l ' o r ­ g a n i z z a z i o n e e t u t t e l e p e r s o n e che e b b e r o l ' a m a b i l i t à d i c o n g r a ­ t u l a r s i con me p e r i l s u c c e s s o d e l l a m a n i f e s t a z i o n e .

L. STANCHI

Voorwoord

Wetenschapsmensen en t e c h n i c i kwamen i n S t r e s a b i j e e n t e n e i n ­ de het " I s p r a Nuclear E l e c t r o n i c s Symposium" b i j t e wonen. Dit i n ­ t e r n a t i o n a l e Symposium werd g e o r g a n i s e e r d door h e t Gemeenschappe­ l i j k Centrum voor Atoomonderzoek van Euratom t e I s p r a en stond on­ der a u s p i c i e n van het " I n s t i t u t e of E l e c t r i o a l and E l e c t r o n i c s En­ g i n e e r s (North I t a l y Section and Nuclear Science Group) met mede­ werking van v i e r I t a l i a a n s e i n s t i t u t e n , t e weten: CNR ( C o n s i g l i o Nazionale d e l l e R i c e r c h e ) , CNEN (Comitato Nazionale per l ' E n e r g i a N u c l e a r e ) , ΑΕΙ (Associazione E l e t t r o t e c n i c a ed E l e t t r o n i c a I t a l i a ­ n a ) , SIF ( S o c i e t à I t a l i a n a di F i s i c a ) .

I n t e r e s s a n t e a r t i k e l e n werden g e p r e s e n t e e r d en ik dank a n e s c h r i j v e r s voor hun medewerking. De complete t e k s t e n van d r i e der aangekondigde a r t i k e l e n werden om v e r s c h i l l e n d e redenen n i e t g e ­ p r e s e n t e e r d . De l e z e r excusere m i j , dat h i j a l l e e n samenvattingen a a n t r e f t . De g e a c c e p t e e r d e a r t i k e l e n werden door een i n t e r n a t i o ­ n a a l comité g e s e l e c t e e r d en i k meen, dat de keuze een goede i s g e ­ weoBt. Het i s d u i d e l i j k , dat een s e l e c t i e , welke i s gebaseerd op samenvattingen, t o t o n j u i e t e r e s u l t a t e n kan l e i d e n en misschien hadden enkele afgewezen a r t i k e l e n een b e t e r e aandacht v e r d i e n d . Bovendien kwamen meerdere a r t i k e l e n b i n n e n , nadat de keuze r e e d s gemaakt was en deze konden daardoor n i e t meer g e a c c e p t e e r d worden. Het programma onderging enkele k l e i n e w i j z i g i n g e n omdat enige g e ­ nodigden hun b e v e s t i g i n g inzonden nadat het programma r e e d s g e ­ drukt was.

O o r s p r o n k e l i j k was v a s t g e s t e l d , dat h e t Symposium d r i e dagen zou duren, maar het b l e e k n u t t i g een v i e r d e dag aan h e t programma t o e t e voegen, t e n e i n d e ook het onderwerp g e s t a n d a a r d i s e e r d e appa­ r a t u u r en i n het b i j z o n d e r de nieuwe'CAMAC­standard" t e kunnen b e ­ h a n d e l n . Een bespreking t e I s p r a , onder s p e c i a a l h i e r v o o r u i t g e ­ nodigde personen, over toekomstige ontwikkelingen was voor dezelfde dag r e e d s v a s t g e s t e l d . De l e z e r verzoek i k mij t e w i l l e n v e r o n t ­ schuldigen voor enkele m i s v e r s t a n d e n , welke h i e r d o o r z i j n o n t s t a a n , doch deze b e s p r e k i n g was v o l l e d i g o n a f h a n k e l i j k van het Symposium. Deze l a a t s t e v i e l samen met de v i e r d e dag, z o a l s voorzien was i n het programma.

Ik dank a l l e personen, d i e medewerkten aan de o r g a n i s a t i e en eveneens de v e l e deelnemers, die mij gelukwensten met het succes van het Symposium.

PAPERS PRESENTED AT THE ISPRA NUCLEAR ELECTRONICS SYMPOSIUM

SESSION 1·· AMPLIFICATION AND ANALOG SIGNAL PROCESSING

CHAIRMAN : K. KANDIAH 1/f Noise in Physical Measurements.

V. Radeka (invited paper) 1

FET Preamplifiers for Semiconductor Radiation Detectors.

E. Elad 2 1

The Development of "n" Channel FET1s for Low Noise Nuclear Pulse Amplifiers.

J.H. Howes 3 S

Realization of Optimum Pulse Shaping Filter.

M. Oda 43

Minimum­Noise Filters with Good Low­Frequency Rejection.

M. O. Deighton 47

Mismatch oriented Circuit Design and its Application to Nuclear Electronics.

A.F. Arbel SS

Signal Shaping, Transformation and Generation, Using Basing Elements of Analog and Digital Computers.

K. Öuljat, Β. Soucek, V. Bonarie, B. Matic 67

Maximum Loop Gain of Feedback Amplifiers with Monotonie Step Response.

H. Babic 73

An Operational Pulse Amplifier with FET­Input.

R. Patzelt, R. Posch 81

Design of a Wideband Pulse Amplifier with Linear Circuit /uA 702A Using Frequency Compensation Technique.

N. P. Lero, P.B. Frantlovié 85

SESSION 2: TIMING

Shaping and Timing Circuits with Alternative Symmetric and Asymmetric Input and Output Configurations.

P. Horvith, L. OndriS 93

Influence of the Compensated Thickness of Coaxial Ge(Li) Detectors and of Noise Sources on Timing Properties.

J.A. Miehé, P. Siffert, R. Stuck, A. Coche 95

Plasma Effects for «­Particles and 016 io n s in Silicon Detectors.

P.A. Tove, W. Seibt, K.E. Sundström ιοί

Digital, Analog and Program Techniques for On-Line Computer Control of Phased Neutron Choppers.

M. C.B. Russell, D.B.J. Smith 107

Time-of-Flight Instrumentation for a Quasielastic Critical Neutron-Scattering Experiment.

E.M. Christiansen, P. Christensen Ill

Differential Linearity Testing and Preoision Calibration of Multichannel Time Sorters.

M. Bertolaccini, S. Cova 119

A Weighted Chronotron for Time-Digit Conversion.

M. Feran, E. Katz, R. Papina 127

Fast Time Marking Discriminator Circuit.

N. Fiebiger, P. Elzer, W.D. Emmerich, A. Hofmann, J. W. Klein 137

SESSION 3: SPECTROMETRY

CHAIRMAN: R.L. CHASE

System Requirements for High Resolution Gamma­Ray Spectrometry at High Counting Rates.

L.O. Johnson, R.L. Heath (invited paper) 141

State of Art in Multichannel Pulse Data Analysis.

B. Soucek 149

Performance Tests for Ge(Li) Spectrometers.

H. Meyer, H. Vereist 171

Fast ADC for Pulse Height Analysis.

R. Kurz 179

Analysis of Nonlinear Feedback Loops in Pulse Stretchers.

I . Alleva, I. De Lotto, P.F. Manfredi, P. Maranesi 193

An Analogue­to­Digital Converter Employing Recycled Successive Approximations.

K. Kandiah, A. Stirling, D.L. Trotman 205

A Normalizing ADC for Use with Position Sensitive Detectors.

G.L. Miller, A. Senator 211

Direct Digitalization of the Quotient of Two Pulse Heights.

W. M. Carpay, S. S. Klein 217

An Analog Spectrum Stabilizer.

Τ. Friese 22\

SESSION U-- MISCELLANEOUS TECNIQUES

CHAIRMAN: J. POTTIER A Data­Handling System for Large­Scale Space Radiation Experiments.

J.B. Reagan, R.D. Reed, J.C. Bakke, J.D. Mattews 225

Compensation of Pulse Deterioration in Miniature Cables by Means of Switching Transistors.

D. Maeder, G. Vuilleumier 231

Deadtime Corrections in a Two­Parameter System Containing Four Detectors.

G. Grosshög 237

A Data Collecting System for Pulse Radiolysis Experiments.

K.E. Neisig, S. O. Nielsen 243

Wire Proportional Counter Arrays with Fast Digital Arithmetic for Decision Making.

L.J. Koester, R.M. Brown, U. Kb'tz, T. Clark, S. Segler, R. Taylor 247 Nucleonic Applications of ErCL Monolithic Integrated Circuits.

Z.H. Cho 251

Multiparameter Analysis and Recording System (MARS) for Isotopes Identification of Transuranium Elements.

B. V.Fefilov, L.P. Chelnokov 259

A Programmed Control and Instrumentation System for a Nuclear Reactor.

J. R. Kosorok (Summary) 263

Digital High­Voltage Supply for Automatio Testing and Regulation of Photomultiplier Gain.

D. Maeder 265

SESSION 5: COMPUTER ON LINE AND DATA REDUCTION IN NUCLEAR EXPERIMENTS

CHAIRMAN: Β. SOUCEK

A Computerized Data Acquisition System for High Event Rates from Many Sources.

D. G. Dimmler

269

Computer System f o r On­Line Neutronic Noise Analysis and C a l c u l a t i o n of Nuclear Reactor Parameter.

M. Carapic, D. Velasevic, S. Stankovic 277

A Computer On­Line i n A c t i v a t i o n Measurements.

L. Arcipiani, U. Farinelli, A. Gibello 283

Use of a Computer On Line i n Experiments a t t h e F a s t C r i t i c a l Assembly SNEAK.

P.L. van Velze, H. Walze 291

NUDIAC­Data Acquisition and Processing System Applied t o Physics Experiments and t o Nuclear Measurements.

J. Moisset, M. Barthélémy 293

An On­Line Data Handling System f o r Physics Experiments a t the Swiss Federal I n s t i t u t e for Reactor Research.

J.B. Bossel, W.Hâlg 299

A CAMAC Multi­User System.

G. C. Best, I.N. Hooton 305

The "ESTER" System for Simultaneous Running of Several On­Line Multiparametric Experiments.

J. Zen, A. Muser, J.D. Michaud, F. Scheibling 307

Data Acquisition and Reduction i n A c t i v a t i o n Analysis by On­Line Computer.

G. Di Cola, F. Girardi, G. Guzzi, A. Termanini 313

Data Handling System for A c t i v a t i o n Analysis by Means of a Small Process Computer.

P. Christensen, E.M. Christiansen 317

A Display Terminal for On­Line Nuclear Experiments.

H.L. Klessmann, J. Zahn 321

Computer Controlled Dataway for Nuclear Informations.

J.F. Gilbert, J.J. Girod, J.L. Lecomte, M. Lesourne (Summary) 331

SESSION 6= STATISTICS AND MATHEMATICAL METHODS

CHAIRMAN: E. BALDINGER

Methods of Reducing t h e Number of Binary D i g i t s Required t o Convey Random Counting­Rate Information.

E.H. Cooke­Yarborough 333

Improvement of S l i d i n g ­ S c a l e Analog­to­Digltal Converters through Weighted Averaging.

E. Gatti, V. Svelto, P.F. Manfredi, P. Thieberger 339

Optimum S t a t i s t i c a l E q u a l i z a t i o n i n Controlled Analog t o D i g i t a l C o n v e r t e r s .

N. Abbattista, B. Marangelli, D.Marino, V. L. Plantamura (Summary) 347 S t a t i s t i c a l E r r o r s of D i r e c t Pulee Rate R a t i o Measurement.

M. Konrad 349

The Measurement of Autocorrelation and Crossoorrelation Functions in the Fast Domain and

its Application to Nuclear Eleotronios.

G.Amsel, R.Bosshard, R.Rausch, M.Sauce, C. Zajde 355

A New General Purpose Correlation Function Computer.

I.H. Quayle 363

Switching C i r c u i t s Optimal Configuration for Amplitude Discrimination and Timing.

N. Abbattista, V.L.Plantamura, G. Giannelli, M. Coli 371

A Method for the Analysis of Complex Gamma-Ray Spectra Using a Computer.

T. Inouye 3 75

SESSION 7: CAMAC AND MODULAR INSTRUMENTS

CHAIRMAN: H. BISBY The CAMAC System of Modular Instrumentation.

R. C. M. Barnes, I.N. Hooton 379

Project AGORA. Adaptive Network for Data Collection and Transmission.

J.F. Mougel 385

CAMAC Crate Control for a PDP8 and a CAMAC 2h Bit Counter.

W. Attwenger, W. Egl, F. May, R. Patzelt, K. Petreczek, J. Schwarzer 3 91

Programmed Control of Autonomous Transfers in a CAMAC System.

J. M. Richards, L.D. Ward 3 95

CAMAC and Modular Instrumentation (A report on the d i s c u s s i o n ) .

H. Bisby, W. Becker, R. C. M. Barnes 3 99

-LIST OF PARTICIPANTS

ABEND K. ­ KFA Jülich, Postfach 365 ­ 517 JÜLICH, Germany.

ACERBONI G. ­ Hewlett­Packard S.A., 7 rue du Bois­ du­Lan ­ 1217 MEYRIN, Switzerland. ADORJAN B . ­ Central Research Institute for Physics of the Hungarian Academy of Sciences, P.O. 49 ­ BUDAPEST 114, Hungary.

ALBERTI G. ­ LABEN, Via Bassini, 15 ­ MILANO, Italy.

ALBERIGI QUARANTA A. ­ University of Modena, Via Vivaldi, 70 ­ 41100 MODENA, Italy. ALLEN K.W. ­ University of Oxford, Dept. of

Nuclear Physics, Keble Road ­ OXFORD, U.K.

ALLEVA I. ­ CISE, Casella postale 3986 f20100 MILANO, Italy

ALOIA A. ­ ENEL, Via G. B. Martini, 3, ROMA, Italy.

AMSEL G. ­ Groupe de Physique du Solide, 9, Quai Saint­Bernard ­ PARIS Ve, France. ANTHONY . ­ CITEC/GIE, 17 route de la Reine ­

PARIS

AQUILI A. ­ CNEN CASACCIA, Casella Postale 2400 ­ 00100 ROMA, Italy.

ARBEL Arie ­ Technion Israel Institute of

Technology , P.O.Box 4910 ­ HAIFA,Israel. ASSADOULAH . ­ Laboratoires de Marcoussis,

C.G.E., route de Nozay ­ 91 MARCOUSSIS, France.

ATTWENGER W. ­ öster. Studiengesellschaft fur Atomenergie, Reaktorzentrum Seibersdorf, Lenaugasse 10 ­ 1082 WIEN VIII, Austria. AUDEBEAU J.P. ­ C.C.R. EURATOM ­ 21020 ISPRA,

Italy.

BABIC H. ­ Institute "Ruder Boskovic" Bijenicka 54, ZAGREB, Yugoslavia.

BALDINGER E. ­ Inst.für Angew.Physik der Univer­ sität Basel, Klingelbergstr. 82 ­ 4000 BASEL, Switzerland.

BALLAND J.C. ­ Institut de Physique Nucléaire 43, Bd. du 11 Novembre 1918 ­

69 VILLEURBANNE, France.

BANERJEE B.M. ­ SAHA Institute of Nucí.Physics 92, A.P.C. Road ­ CALCUTTA, India. BANERJEE P. ­ SIEMENS A.G., Gellertstrasse 38,

75 KARLSRUHE, Germany.

BARBIEUX Ph.­ Cie Internationale pour l'Informa­ tique, 68 route de Versailles ­

78 LOUVECIENNES, France.

BARNES R.C. ­ A.E.R.E., HARWELL, Didcot, Berks., U.K.

BARTHELEMY M. ­ C.E.A.­C.E.N./SACLAY, B.P. N.2 ­ 91 GIF­sur­YVETTE , France.

BATTISTA A. ­ TENNELEC Inc., P.O.B. D ­ OAK RIDGE, TENN. 37830, U.S.A.

BECKER L. ­ C.C.R. EURATOM ­ 21020 ISPRA , Italy BECKER W. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy BERANGER R. ­ INTERTECHNIQUE ­ 78 PLAISIR,France. BERNEDE M. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. BERTOLACCINI M. ­ Istituto di Fisica del Poli­

tecnico, P.zza Leonardo da Vinci, 32 ­ 20133 MILANO, Italy.

BISBY H. ­ A.E.R.E. HARWELL, Didcot, Berks., U.K. BOCCIOLDH M. ­ Istituto Nazionale Fis .Nucí.

Largo E . Fermi, 2 ­ FIRENZE, Italy. BONNAURE P. ­ C.C.R. EURATOM ­ 21020 ISPRA,Italy. BONSIGNORI C. ­ LABEN, Via Bassini 15­20133

MILANO, Italy.

BORER A. ­ BORER & CO., ELECTRONICS, 45 SOLOTHURN 2 , Switzerland.

BOSSEL J.B. ­ Swiss Fed.Inst. Reactor Research 5303 WURENLINGEN, Switzerland. BOSSHARD R. ­ Accélérateur Linéaire ­ Bât. 200

91 ORSAY, France.

BOUCKE G. ­ AEG­TELEFUNKEN, Forschungsinstitut Elisabethenstr. 3 ­ 7 9 ULM, Germany. BOUSSARD D. ­ C.E.R.N. ­ 1211 GENEVA 23,

Switzerland.

BOYCE D.A. ­ A.E.R.E., HARWELL, .Didcot, Berks., U.K.

BREHM H. ­ Inst. fur Angew. Physik, Universität Frankfurt/tø. Am Forsthaus Gravenbr.28 ­ 6O78 NEU ISENBURG 2, Germany.

BRET Α. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. BRISCOE W.L. ­ Los Alamos Laboratory ­

LOS ALAMOS/NEW MEXICO, U.S.A.

BROOKS J.R. ­ Science Research Council,Daresbury Nuclear Physics Lab. WARRINGTON/Lancs. U.K.

BÜSCHTNG E . ­ Labor Prof .Dr. Berthold, Postfach 160 ­ 7547 WILDBAD, Germany.

CARAGHEORGHEOPOL G. ­ Institute for Atomic Physics BUCHAREST, Rumania.

CARAPIC M. ­ Nuol.Sci.Inst. "Boris Kidrich" P.O.B. 522 ­ VINCA­BEOGRAD,Yugoslavia. CERVELLATI R. ­ CNEN CASACCIA, Casella Postale

2400 ­. 00100 ROMA, Italy.

CHASE R.L. ­ Brookhaven National Lab. UPTON L.I. N.Y. 11973, U.S.A.

C m S M O N N. ­ Electronic Assocates Ltd. Victoria Rd. BURGESS HILL/Sussex , U.K. CHO Z.H. ­ Institute of Physics, Stockholms

University ­ STOCKHOLM, Sweden.

CHRISTENSEN P. ­ Danish Atomic Energy Commission Riso ­ 4000 ROSKILDE, Denmark.

CHRISTIANSEN E.M. ­ Danish Atomic Energy Commis­ sion RisS ­ 4000 ROSKILDE, Denmark. CINISELLI C. ­ C.C.R. EURATOM ­ 21020 ISPRA,Italy. COTANTE D. ­ CNEN CASACCIA, Casella Postale 2400

00100 ROMA, Italy.

COLI M. ­ Laboratori Nazionali di Frascati del CNEN, C.P. 70 ­ 0044 FRASCATI, Italy. COLLINSON A.J.L. ­ Borough Polytechnic, Borough

Road ­ LONDON S.E.1, U.K.

COLOMBO A. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. COLOMBO G. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. CONRAD R. ­ HAHN­MEITNER INSTITUT, Glienicker Str.

100 ­ 1 BERLIN 39, Germany. COOK A.D. ­ Cambridge Scientific Inst. Co.,

Chesterton Road, CAMBRIDGE, UK. COOKE­YARBOROUGH E. ­ A.E.R.E., HARWELL, Didcot,

Berks., U.K.

COPPO N. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. COTTINI C. ­ CISE, Casella Postale 3986 , 20100

MILANO, Italy.

COURBOIS Th. Harshaw Chemie Ν.V. Strikjkviertel 95 ­ DE MEERN, Netherlands.

COVA S. ­ Istituto di Fisica del Politecnico, P.zza Leonardo da Vinci, 32, 20133 MILANO, Italy.

COWAN R.C. ­ Precision Metal Fabricators, 540 Lewelling Blvd. SAN LEANDRO, CALIF. U.S.A.

CUBIOTTI G. ­ Istituto di Fisica, Università di MESSINA, Italy.

CULJAT K. ­ Institute "Ruder Boskovic1", Bijenicka o. 54 ­ ZAGREB, Yugoslavia.

DE BRUIN M. ­ Reactor Institute, Berlagweg 15, DELFT, Netherlands.

DE AGOSTINO E. CNEN CASACCIA, Casella Postale 2400 ­ 00100 ROMA, Italy.

DEIGHTON M.O. ­ A.E.R.E. HARWELL, Didcot, Berks., U.K.

DE JONGE S. ­ B.C.M.N. EURATOM GEEL, Steenweg naar Retie, Belgium.

DE LOTTO I. ­ CISE, Casella Postale 3986, 20100 MILANO, Italy.

DEMARCHI G. ­ GAMMATOM S.p.A., via 25 aprile, 22070 GUANZATE. Italy.

DEMUYNCK J. ­ University Ghent, K. van de Woestynestr. 12 ­ ZWYNAARBE,Belgium. DIETTRICH 0. ­ C.C.R. EURATOM ­ 21020 ISPRA,

Italy.

D'OLSON F. ­ INTERTECHNIQUE ­ 78 PLAISIR, France. DOTTI D. ­ CISE, Casella Postale 3986 ­ 20100

MILANO, Italy.

DRUZETA A. ­ Institute "Ruder Boskovic1 ", Bijenicka e. 54 ­ ZAGREB, Yugoslavia. DURCANSKY Q. ­ KFA Jülich, Postfach 365, 517

JÜLICH, Germany.

EDER J. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy.

ELAD E. ­ Nuclear Diodes Inc. P.O.B. 135 ­ PRAIRIE VIEW, ILL., U.S.A.

ELEK G. ­ Central Research Institute for Physics P.O.Box 49 ­ BUDAPEST 114, Hungary. EQUTLBEY S. ­ Ministère de l'Education Nationale

CNRS, 15 rue G. Clemenceau ­ 91 ORSAY, France.

FARAGO H.­ Central Research Institute for Physics P.O.Box 49 ­ BUDAPEST 114, Hungary. FEFILOV B.V. ­ Joint Inst.for Nucl. Research

DUBNA, P.O.B. 79 MOSCOW, USSR.

FELLMANN S. ­ Physikalisches Institut der Univer­ sität Marburg/Lahn, Renthof 5 MARBURG/ Lahn, Germany.

FESTA E. ­ Institut de Physique Nucléaire, Β.P. 1 91 ORSAY, France.

FIEBIGER N.­ Physik.Inst, der Universität 852 ERLANGEN, Germany.

FIEGNA G. ­ Ist. Fisica Tecnica del POLITECNICO Corso Duca degli Abruzzi, TORINO, Italy. FINZI S. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. FIORONI F. ­ CNEN CASACCIA, Casella Postale 2400,

00100 ROMA, Italy.

FISCHER P.M. ­ Gesellschaft für Kernforschung Lab. f. Elektr. u. Messtechnik , Weberstr. 5 ­ 7 5 KARLSRUHE, Germany. FRANTLOVre P. ­ Nucl.Sc.inst. "Boris Kidrieh"

P.O.B. 522 ­ VINCA­BEOGRAD, Yugoslavia. FREYCENON J. ­ C.E.N. ­ Cadarache, B.P. N.1 ­

ST­PAUL les DURANCE, France. PRIANT . ­ C.E.A. ­ C.E.N. Saclay, DEG/SER

B.P. N.2 ­ 91 GIF­sur­YVETTE, France. FRIESE Th. ­ Hahn­Meitner Institut, Glienicker

Str. 100 ­ 1 BERLIN 39 , Germany. FRUMAU C.F.A. ­ Reactor Centrum Nederland,

PETTEN (N.H.) Netherlands.

GANSS Β. ­ C.C.R. EURATOM 21020 ISPRA, Italy. GARAGNANI G.C. ­ ENEL, V.le Regina Margherita

137 ­ ROMA, Italy.

GATTI E. ­ CISE and POLITECNICO di Milano, C.P. 3986 ­ 20100 MILANO, Italy. GEDCKE D. ­ ORTEC Inc. 100 Midland Road,

OAK RIDGE, TENN. U.S.A.

GIACOMICH R. ­ Istituto di Fisica, Via Valerio 2 TRIESTE, Italy.

GIBELLO Λ. ­ CNEN CASACCIA, Casella Postale 2400, 00100 ROMA, Italy.

GOLDER J. ­ Institut für Angew.Physik der Univer­ sität Basel, Klingelbergstr. 82, 4000 BASEL, Switzerland.

GOLUTVTN I.A. ­ Joint Inst, for Nucl. Research DUBNA ­ P.O. Box 79 ­ MOSCOW, USSR. GOYOT M. ­ Institut de Physique Nucléaire , 43

Bd. du 11 novembre 1918 ­ 69 VILLEURBANNE, France.

GRANATA L. ­ Istituto di Fisica, Via Valerio 2 34100 TRIESTE, Italy.

GUILLON H. ­ C.E.A.­C.E.N. Saclay B.P. N.2. 91 GIF­sur­YVETTE, France. GUREWITSCH A.M. ­ GENERAL ELECTRIC CO. USA

Research & Development Center

Lbwenstr. 29 ­ 8001 ZURICH, Switzerland. GUYON .­ Institut de Physique Nucléaire, 43

Bd.du 11 Novembre 1918 ­ 69 VILLEURBANNE, France.

GUZZI G. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. HALLER E . ­ Institut für Angew. Physik der Uni­

versität Basel, Klingelbergstr. 82 4000 BASEL, Switzerland.

HARGROVE C K . ­ National Research Council of Canada, 100 Sussex Drive ­ OTTAWA, CANADA.

HAURIE Y. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. HEATH R.L. ­ Idaho Nuclear Corporation, P.O. Box 1845, IDAHO FALLS, IDAHO 83401, U.S.A. HEELAS . ­ Dynatron Electronics, St. Peters

Road ­ MAIDENHEAD, U.K.

HØY­CHRISTENSEN P. ­ Danish Atomic Energy Com­ mission RisB ­ 4000 ROSKILDE,Denmark. HOLMQVIST B. ­ A.B. Atomenergi, Studsvik,

NYKÖPING, Sweden.

HORVATH P. ­ Joint Inst.for Nucí.Research DUBNA, P.O.B. 79 MOSCOW, USSR.

HOWES J.H. ­ A.E.R.E., HARWELL, Didcot, Berks., U.K.

HRISOHO .­ Institut de Physique Nucléaire, B.P. N.1 91 ORSAY, France. HUGHES G. ­ Science Research Council, DN.P.L

DARESBURY ­ WARRINGTON, U.K.

IDZERDA A.B. ­ B.C.M.N. EURATOM GEEL, Steenweg naar Retie, Belgium.

INOUÏE T. ­ Central Research Lab. Tokyo Shibaura Electric Co., Ltd. 1 Komukai Toshiba­ Cho, Kawasaki­Shi, Kanagawa­Ken, Japan.

ISELIN F. ­ C.E.R.N. NP. Div. ­ 1211 GENEVA 23 Switzerland.

JACQUIN M. ­ Institut de Physique Nucléaire, 43, Ed. du 11 Nov. 1918 ­

69 VILLEURBANNE, France.

JEDLOVSZKY R. ­ National Office of Measures XII. NémetvBlgyi ut 37­39 ­ BUDAPEST, Hungary.

JONSSON G. ­ AB Atomenergi ­ Studsvik ­ NIKOPING Sweden.

JOVIC F. ­ Institute "Ruder Boskovic* " Bijenicka c. 54 ­ ZAGREB, Yugoslavia.

KADJAR .­ 38 rue Gabriel Crié, SAIP ­ 92 MALAKOFF, France

KANDIAH K. ­ A.E.R.E., HARWELL, Didcot, Berks., U.K.

KATKIEWICZ W. ­ Central Radiological Protection Laboratory, Modlinska 15 ­ WARSAW, Poland.

KEDDAR A. ­ I.A.E.A. KKrntnerring 11­13 , 1010 VIENNA, Austria.

KEROE E . ­ I.A.E.A. Kärntnerring 11­13 ­ 1010 VIENNA, Austria.

KESSEL W. ­ Institut für Kernphysik , Aug.Eulor­ str. 6 ­ FRANKFURT/tø., Germany. KISLEV A. ­ Nuclear Research Centre­Negev ,

P.O.B. 9001 ­ BEER SHEVA, Israel. KLEIN J.W. ­ Frieseke u. Hoepfner ­ 852 ERLANGEN­

BRUCK, Germany.

KLEIN S.S. ­ Technological University, Insulinde­ laan ,(P.B.513) EINDHOVEN, Netherlands. KLESSMANN H. ­ Hahn­Meitner Institut, Glienicker­

Str. 100 ­ 1 BERLIN 39, Germany. KOBUS L. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. KOECHLER C. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy.

KOEMAN Η. ­ I.K.O. Ooster Ringdijk 18,AMSTERDAM­O Netherlands

KOESTER J. ­ Physics Department, University of Illinois ­ URBANA, ILL. 61801, U.S.A KOLBE W. ­ Labor. Prof. Dr. Berthold, Postfach

160 ­ 7547 WILDBAD, Germany.

KONRAD M. ­ Institute "Ruder Boskovic' " Bijenicka c. 54 ­ ZAGREB, Yugoslavia.

KONY J. ­ C.E.A.­C.E.N. SACLAY ­ D.C.E. B.P. N.2 91 GIF­sur­YVETTE, France.

KORTHOVEN P.J.M. ­ Reactor Institute, Berlageweg 15 DELFT, Netherlands.

KOSSIONIDES E. ­ G.A.E.C. 7, Sandileigh Ave. MANCHESTER 20, U.K.

KOUVARAS N. ­ N.R.C. DEMOKRITUS, Aghia Paraskevi­ Attikis ­ ATHENS, Greece.

KOVACS E.­ Central Research Inst, for Physics P.O.Box 49 ­ BUDAPEST 114, Hungary. KRUISKAMP M. ­ KEMA Suspension Test Reactor,

Monnikensteeg IO8, ARHHEM, Netherlands. KUMPF S. ­ C.C.R. EURATOM ­21020 ISPRA, Italy. KURZ R. ­ TENNELEC, P.O.Box D, OAK RIDGE, TENN.

3783O, U.S.A.

LAGONEGRO M. ­ Istituto di Fisica di Trieste Via Valerio, 2 ­ 34100 TRIESTE, Italy. LAGOYANNIS D. ­ N.R.C. DEMOKRTTUS, Aghia Paraskevi­

Attikis ­ ATHENS, Greece.

LANGKAU R. ­ I. Inst, für Experimentalphysik Jungiusstr. 9 ­ 2 HAMBURG 36, Germany. LECLERC J. ­ CITEC/O.I.E. 17, route de la Reine

92 BOULOGNE, France.

LECOMTE J. ­ C.E.A.­C.E.N.G. ­ CEDEX Ν. 85 ­ GRENOBLE­GARE, France.

LEPERS Α.­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. LERO N. ­ Nuol.Sci.Inst. "jBoris Kidrioh" ,

P.O.B. 522 ­ VINCA­BEOGRAD, Yugoslavia. LEVY J. ­ CITEC/G.I.E., 17 route de la Reine,

92 BOULOGNE, France.

LIDOFSKY L. ­ Pegram Nuclear Physics. Lab., Columbia University, 538, West 120th Street, NEW YORK, N.Y. 10027, U.S.A. LOURENS W. ­ Technische Natuurkunde, Lorentzweg

LUGOL J.C. ­ C.E.A.­C.E.N. SACLAY, Β.Ρ.N.2 , 91 GIF­sur­YVETTE, France.

MACLENNAN D.N. ­ D.A.F.S. MARINE Lab., Victoria Road, P.O.B. 101, ABERDEEN, U.K. MAEDER D.G. ­ Ecole de Physique, Univ. de Geneve,

Bid. d'lvoy 32, 1211 GENEVA 4, Switzer­ land.

MALOSTI D. ­ CNEN CASACCIA, Casella Postale 2400 00100 ROMA, Italy.

MANDL V. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. MANFREDI P.F. ­ CESNEF, Politecnico di Milano,

Via Pascal 3, MILANO, Italy.

MARACCI G.C. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. MARANESI P. ­ CESNEF, Politecnico di Milano,

Via Pascal 3, MILANO, Italy.

MASKELL S. ­ Science Research Council Rutherford Lab. CHILTON, Berks., U.K.

MEILING W. ­ Zentralinstitut für Kernforschung Postfach 19 ­ 0051 DRESDEN, Germany. MERDINGER J.C. ­ Université de Strasbourg, Inst,

de Recherches Nucléaires, B.P. N. 16 CR 67 STRASBOURG 3, France.

METZDORF J. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. MEY J. ­ C.E.A.­C.E.N.G. CEDEX N. 85 ­ 38 GRENOBLE­

GARE, France.

MEYR H.P. ­ Swiss Federal Institute for Reactor Research ­ 5303 WÜRENLINGEN, Switzerland. MEYER H. ­ B.C.M.N. EURATOM GEEL, Steenweg naar

Retie, Belgium.

MICHAUD J.D.­ Université de Strasbourg, Institut de Recherches Nucléaires, B.P. N. 16 CR 67 STRASBOURG 3, France.

MIEHE J.A. ­ C.R.N. Physique des Rayonnements et Electronique Nucléaire, Rue du Loess, 67 STRASBOURG­CRONENBOURG, France. MILLER G.L.­Bell Telephone Lab. Mountain Avenue,

MURRAY HILL, N.J. 07974, USA

MOLINARI M.A. ­ Université de Strasbourg, Inst. de Recherches Nucléaires, B.P. N.16 CR 67 STRASBOURG 3, France.

MOL M. ­ C.C.R. EURATOM ­ 21020 ISPRA, Itali'. MOLL G. ­ TOTAL ­ 6802 LADENBURG, Germany. MOUGEL J.F. ­ C.E.A.­C.E.N. SACLAY, B.P. N2.

91 GIF­sur­YVETTE, France.

MULLER K.D. ­ KFA Jülich, Postfach 365 ­ 517 JÜLICH, Germanyí

MUSER Α. ­ Université de Strasbourg, Institut de Recherches Nucléaires, B.P. N. 16 CR 67 STRASBOURG 3, France.

NAJZER M. ­ Nucl.Institute "J. Stefan" Jamova 39 LJUBLJANA, Yugoslavia.

NEISIG K.E. ­ Danish Atomic Energy Commission Rls'd ­ 4000 ROSKILDE, Denmark. NETZBAND D. ­ ZfK Rossendorf, Postfach 19 ­

8051 DRESDEN , Germany.

NIESTROJ D. ­ Frieseke & Hoepfner GmbH, Tennen­ loher Strasse ­ 852 ERLANGEN, Germany.

ONDRIS L. ­ Joint Inst.for Nucl. Research DUBNA, P.O.B. 79 MOSKOW, USSR. OTTES J. ­ Ges. für Kernforschung, Lab. für

Kernforschung Lab. f. Elektr. u. Mess­ technik, Weberstr. 5 ­ 7 5 KARLSRUHE, Germany.

PAGNOTTE .­ Institut de Physique Nucléaire, 43 Bd. du 11 Novembre 1918, 69 VILLEURBANNE France.

PAIN J. ­ C.E.A.­C.E.N. SACLAY , B.P.N. 2 , 9'l GIF­sur­YVETTE, France.

PATRUTESCU M. ­ Institute for Atomic Physics P.O.B. 35, BUCHAREST, Rumania.

PATZELT R. ­ Osterr. Studienges, für Atomenergie Lenaugasse 10 ­ 1082 V/IEN VIII, Austria. PEDRINI A. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. PELLEGRINI U. ­ LABEN, Via Bassini 15 ­ 20133

MILANO, Italy.

PETEL M. ­ C.E.A. B.P. Ν. 510, 75 PARIS XVe, France.

PETERSEN J. ­ Danish Atomic Energy Commission Riso ­ 4000 ROSKILDE, Denmark.

PHILIPPE A. ­ C.C.R. EURATOM ­ 21020 ISPRA, Italy. PIRRONE G. ­ AMP ITALIA, Corso F.Ili Cervi, 15

IOO93 COLLEGNO (TO), Italy.

PLATTNER R. ­ ORTEC ­ Am Birkicht 6 MÜNCHEN, Germany.

POENARU D.N. ­ Institute of Atomic Physics, P.O.B. 35 ­ BUCHAREST, Rumania. POTTIER J. ­ C.E.A.­C.E.N. ­ SACLAY, B.P. N.2

91 GIF­sur­YVETTE, France.

PRATO Α. ­ ENEL , via G.B. Martini, 3 ROMA, Italy.

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-XVI-1/|fI NOISE IN PHYSICAL MEASUREMENTS *

Veljko Radeka

Brookhaven National Laboratory

Upton, N. Y.

Summary

The purpose of this paper is to pro­

vide an insight into low frequency diver­

gent noises with spectral density | f

| ,

where

α * ­1 , and into their effect

on physical measurements, with special

reference to 1/|f| noise. This class of

noise is widespread in nature, and it

presents unique limitations to the

measurement accuracy. In an attempt to

present a picture of this class of noise

with regard to the measurements of ob­

servable physical quantities, the ques­

tions about generation of noise, its

divergence, correlation properties and

measurements of variance are discussed.

A statistical model for generation

of low frequency divergent noises is used

to consider the divergence problem in

both the frequency and time domain. It

is shown that 1/|f| noise is "weakly

divergent," and that power limitation

presents no reason to impose a low fre­

quency limit within time intervals ob­

servable in nature. Correlation proper­

ties are discussed in terms of the time­

dependent correlation function, using

an ideal impulse response which generates

low frequency noise from white noise.

Two general models for generation of

1/|f| noise are summarized and discussed.

Generation of 1/|f| noise from white

noise over a limited frequency range by

distributed and lumped­parameter filters

is described.

It is shown that the variance (i.e.

mean square noise) is determined by the

frequency limits of the observation method.

The variance is independent of the low

frequency limit of noise, if such a limit

exists, and if the frequency limit of

noise is lower than the low frequency

limit of the measurement process. If

the ratio of the high frequency limit

and the low frequency limit of the

measurement process is constant, the

variance is a function of one parameter,

τ, which is proportional to the "measure­

ment time." For power­law noises, the

variance σ « τ

. Variance in the case

of a general power spectral density func­

tion can be represented by the power

series, where each term τ

may be

associated with a power­law noise compon­

ent. Thus, the measurement of variance

as a function of measurement time repre­

sents a method for identification of

power­law noises, and their effect under

actual measurement conditions.

1. Introduction

The purpose of this paper is to

provide an insight into low frequency

divergent noises with spectral density

|f|

,

where α * ­1 ,

and into their

effect on physical measurements, with

special reference to 1/|f| noise. The

class of noise |f|

with α close to minus

one is widespread in nature and it pre­

sents unique limitations to the measure­

ment accuracy. Even in cases where the

signal energy can be increased arbitrar­

ily by extending the measurement time,

the accuracy of the measurement of the

signal magnitude cannot be improved by

increasing the measurement time.

The basic distinction between white

noise and 1/|f| noise is that the span of

interdependence between samples is very

large for 1/|f| noise, while sufficiently

spaced samples for white noise (and for

bandlimited white noise) are independent.

This can be expressed in terms of correla­

tion functions, that, while the correla­

tion function for white noise is the

delta function (in the limit of infinite

bandwidth), the correlation function for

♦This work was performed under the

auspices of the U.S. Atomic Energy

Commission.

low frequency noises (to the extent that

it can be defined) decreases only very

slowly with the interval between samples.

The basic feature of any noise-generating

mechanism for low frequency divergent

noises is an "infinitely long memory"

for individual independent perturbations.

Integration of white noise generates

noises with spectral density |f|

,

where

α - -2i, and i is the order of integra­

tion. One "integer-order" integration

converts white noise into 1/f noise, or

"random walk." One "half-order integra­

tion" is required to obtain 1/|f| noise

from white noise. Noises which are re­

lated to white noise by an "integration"

of a fractional-order are sometimes re­

ferred to as "fractional noises." Noises

with spectral density |f|

, where-a is

close to unity, observed over a certain

frequency region, have been referred to

as "flicker effect," "excess noise," "low

frequency noise," "contact noise," and

"pink noise."

1/| f| noise has been observed as

electrical noise or as fluctuations of

some other physical quantity, or, more

generally, of a "process variable" in a

number of different devices and physical

and other systems. It was discovered in

electron tubes as "flicker effect.

'^

It was also observed in all semiconductor

devices which could have any application

for amplification and detection of small

signals.

' '

Some semiconductor devices

have particularly large 1/|f| noise, for

example, MOS transistors as compared to

junction field-effect transistors. Noise

in MOS transistors has recently been a

subject of extensive studies.

' '

Low frequency fluctuations appear to be

the principal limiting factor on the

accuracy of frequency and time measure­

ments and on the stability of precision

signal generators.

'

'

»

»

1/|f|

fluctuations have been found also in a

biological system. Fluctuations in the

frequency of rotation of the earth

>'»

appear to have a frequency spectrum with

α = -2 over a certain region. The concept

of fractional noises has also been invoked

to study the fluctuations of variables

in economics.

° It is also known that

nuclear reactors with their feedback

control exhibit power fluctuations which

have 1/|f| spectral density over a range

of frequencies. This noise presents a

limitation in some nuclear physics ex­

periments. Noises with spectral density

represented approximately by the sum of

white, 1/|f| and 1/f densities impose a

limit on the measurement resolution of

charge-sensitive amplifiers for nuclear

radiation detectors. One source of 1/|f|

noise in this case seems to be

frequency-dependent thermal noise of solid dielec­

trics.

The mechanisms of generation of 1/|f|

noise in particular physical situations

have been little understood. In the vast

amount of literature on observed low fre­

quency noises a satisfactory explanation

of mechanisms was provided only in a few

cases. Recently more insight has been

gained as to how 1/|f| noise could be

generated, and several models and inter­

pretations have been proposed.

»14,19

The most general model is the mechanical

model proposed by Halford,

in which

broad classes of perturbations are shown

to be able to generate a given spectrum.

This model leads also to analog and digi­

tal schemes for generation of low fre­

quency noise for simulation purposes.

1/|f| noise has received very little

attention from the point of view of

signal processing in the literature on

statistical communication theory. Some

mathematical studies of fractional noises

have been published (other references

are given in Ref. 18), where a number of

problems of mathematical nature have been

raised.

Measurements of physical quantities

in the presence of low frequency fluctua­

tions have been considered in greater

detail in some special areas. The measure­

ments of frequency and time have been

analyzed extensively,

»

"»

^ and

frequency spectrum represented by a nega­ tive power series has been considered by Gatti and Svelto. Dependence of the noise power (variance) on the measurement time has been used for some time in this field to identify | f| α noise components with different exponents. Consideration of dependence of noise on other variables has led to identification of physical

a+1.

sources of noise in charge amplifiers. 20 The effect of 1/| f| noise on nuclear magnetic resonance (NMR) measurements was discussed by Klein and Barton. 22

In this paper an interpretation of low frequency noises and of the divergence problem is presented. A note is made on the difficulties with the definition of the correlation function for divergent noises, and on the characterization of their correlation properties. Models and mechanisms for generation of 1/|f| noise are reviewed, and an example of a circuit is given for generation of l/l f| noise. Some effects of 1/|f| noise on the pulse amplitude measurements and on repetitive measurements in NMR are discussed. The method for identification of power­law noises based on time domain measurements is described. The interpretation and the models discussed here are based on linear superposition of perturbations generated by a stationary process, which should result in a divergent noise process with stationary increments. Problems arising from, more complex processes with non­ stationary behaviour are indicated.

2. An Interpretation of Low Frequency Divergent Noises Representation of Noise and Divergence Tests

Power­law noises are represented as (1) wa(f) = | f |a

wa(f) W (f)/W (0) is the normalized one· α α

sided spectral density as a function of cycle frequency.

square value of the fluctuating variable (w (0) is the mean

α

for voltage 1/| f | at 1 Hz per Hz

noise w_x(f) = v2~(f)/Af, where Af=W_1(0) is expressed in volts2.) Of particular interest here are the cases of white noise (a=0), 1/|f| noise (a ­ ­1) , and "random walk" (a = ­2) , since they appear most

frequently and since white noise and random walk represent interesting limit cases for comparison with 1/|f| noise. Power­law noise can be considered as being generated by a Poisson process act­ ing upon an appropriate filter.1 3 In the frequency domain, the transfer function of the filter which converts white noise into power­law noise is

H(u>) = (JOJ) (2)

In the time domain, we think of the power­ law noise as being generated by the random sequence of impulses, each impulse gener­ ating at the output of the filter an

impulse response, h ( t ) , which is the Fourier transform of the frequency domain transfer function H (ID),

­g­1 h(t) =

r< * α

­ 2 ­ ­ a

«­ 1

(3)

(Campbell and Foster, α = ­ 2 , Γ(τ) = 1. for

23

pair 516.) For Ùi _„l/2 2(­α­1)/2.π

­ 1 , Γ(7)=ττ ■α/2"

(The coefficient 2X ' ■""''"•π *" ' is due to the normalization of all the variances, calculated in the following, to the one­ sided spectral density W (0) at 1 Hz.) If the input white process is x ( t ) , the process at the output of the filter is convolution y(t) = x(t) *h(t),

­α­I _ a

o

o

t

^

­\

y(t) =

ini

/

a 2

(t­u) x(u)du (4)

y(t)

f—

1

i

(t-u)

1/2 χ ( u) du (5)

The impulse response of the filter for conversion of white noise into 1/|f| noise is

h(t) _1/2 for t > 0

(6) = 0 for t <. 0

The concept of the generation of various basic noises by a Poisson process is illustrated in Fig. 1. Fig. 1(b) shows the physical white noise - with high-frequency cutoff [impulse response

— exp (-t/τ,) is shown resulting in the

Th n

2 2

spectrum 1/(1 + w τ, ) and autocorrelation function r(T) = exp(-|τ|A, ) .] The main distinction of low-frequency noises is that each impulse of the random process produces an effect of infinite duration (constant for random walk, and a slowly decaying one for 1/|f| noise).

As a divergence test in the fre­ quency domain, total power (variance) in the frequency band limited by frequencies f„ and f, can be calculated _{i h}

σ ( fh >f^

=ƒ Ifl

at "both limits for α = -1. Thus, the unique place of 1/|f| noise among power-law noises is that it is divergent at both frequency limits. Low frequency divergent noises are characterized by α s -1. The high frequency divergence presents no actual problem, since in any physical system there is a high frequency

limit, and infinite power at high fre­ quencies cannot exist. For analytical purposes it can be handled by introducing an approperiate high frequency cutoff

(which is a realistic solution, since any method for observation of noise introduces a high frequency limit) .

To get closer to the substance of low frequency divergence, a time domain divergence test can be applied. In this test we imagine that the Poisson process is switched-on at the input of the filter h(t), which converts it into power-law noise, and then we observe the output mean square noise power (variance) as a function of time, as illustrated in Fig. 2. There are a number of different approaches to calculate this. The most plausible one in this case is to apply Campbell's theorem, and to determine the effect of input impulses occurring in the interval 0,t on the output at time t, as the sum of mean square contributions by independ­ ent impulses. The output due to a single impulse q-6(X) will be q.h(\) at a time (λ) after the impulse occurred. For the random sequence with mean rate fi, the mean square output due to ñdX impulses in the interval d\ will be ñq h2(X)d\, and the output for the whole interval (0,t) is obtained by the integral

JL_

l+a

1+a L h

In

(7) ­ f /+ a] for c^­1

for a= ­1

2,,. „v ­ 2

σιτ (t,0) = nq

¡y

U)dX

_ 2

Noting that nq is the (two­sided) power spectral density of the input process, the normalized output variance is Extending the frequency band f. ­ 0 and

f, ­> <=, the total power tends to infinity, at the low frequency limit for α < ­ 1 , at the high frequency limit for α > ­ 1 , and

(t,0)

ƒ

h U)dX

For power-law n o i s e , u s i n g Eq. (3) , i t

follows,

-α-I -a „ _

(10)

- a - 1 - a , ,

2 π 1_ . - a - 1 , .

_{t for a < - 1}

Criftf

- a - 1

For a = - 1 , integral (10) gives ¿n xj , and the lower limit presents a problem due to infinite power of 1/|f| noise at high frequencies. This can be solved by introducing a high frequency cutoff. One way is to introduce averaging over a

short time interval 6. The "smoothed" impulse response for a = -1 is

t+6

h(t,6) = ì ƒ h(u)du

(11) = ? -[ ( t + 6 ) 1/ 2 .t 1/ 2]

o

-1/2

Impulse response (t/δ) and the "smoothed" response h(t,6) are shown in

Fig. 3, curves a and c. While Eq. (11) gives the effect of sampling with a finite integration time 6, a function similar to this (curve b) can be used, as it results in somewhat simpler calculations.

(Both curves affect only the high fre­ quency respons e.)

Variance as a function of time for 1/| f| noise is then

τ. υ

a2(t,0) = ^ ƒ dX + ƒ ì dX o

't/δ for t <; δ

(12)

«■ 1 + £n(t/ô for t a o

Thus, for various low frequency divergent noises, we have:

w

f) =

i/l

f 1

1/f

i/l

f I

i / f

α =

a

( t , 0 ) «

An(t/6)

t3

(13)

For low frequency divergent noise, the variance increases in time without limit. This brings up the question of the existence of the low frequency limit. Must it exist? The divergence of the 1/|f| noise is so weak that the variance in­ creases very little over a large range of time. According to the argument of

F l i n n ,5 if the low frequency limit corre­ sponds to current estimates of the age of the universe (­v.10 Hz) , and the highest frequency to the time taken for light to traverse the classical radius of the electron (^10 Hz) , this would represent 40 decades, and in that time the rms noise would increase only /40 times the value for one decade. In many measurements ■the averaging time δ is increased with the

observation interval t (the ratio of cut­ off frequencies remains the same). In that case one measures a constant power for 1/|f| noise.

Noises with α = ­2 and α = ­3 are strongly divergent, and they cannot exist without a low frequency limit for any variable which has an upper bound, or a dynamic range limit in the sense of electronic systems. However, they can exist if the variable has no such bound

(variables accumulated in time, phase of an oscillator, for example).