(SLAC PUB 1249) Preprint SEARCH FOR MAGNETIC MONOPOLES ...

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of material returned by the. Apollo ii,. 12, and. 14 missions, using a mod- ified .... with comparable limits set by other recent exper- iments. 7-9 using different.

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and Addenda (SLAC

SEARCH MATERIAL

FOR MAGNETIC MONOPOLES USING AN ELECTROMAGNETIC

Ronald Luis

Prepared

R. W.

Ross, Alvarez

for the U. S. under Contract

Philippe H. and Robert

IN LUNAR DETECTOR

Eberhard, D. Watt

Atomic Energy W-7405-ENG-48

LBL-I 730 PUB 1249) Preprint

Commission

-j-

MAGNETIC MONOPOLES AN ELECTROMAGNETIC

Robert

and D.

Watt

12,

in lunar

LBL-

using

1730

of

mo-

a mod-

kg

has been 11.5

MATERIAL

-4

rays

and for

mo-

and update

monopoles/g

of our

no magnetic

of an additional

Again, with

in cosmic

surface

of 1.7 10

the results

and 14 missions,

1971

monopoles

ABSTRACT magnetic in April ii,

materials

IN LUNAR DETECTOR’

R. Ross, Philippe H. Eberhard, and Luis W. Alvarez

for

Stanford Linear Acclerator Stanford, California

search the exploration by the Apollo detector. results

these

Combining

electromagnetic

Center 94305

Lawrence Berkeley Laboratory University of California Berkeley, California 94720

Ronald

SEARCH FOR USING

Our with

of our

concluded

version detected.

returned

ified was

material

nopole

limit

flux

in the lunar

we set an upper monopoles

experiment, of isolated

section.

the monopole cross

set for

production

limits

the density

previous for

pair

our upper nopole

search

reported.

Our has been

for 1

-2-

INTRODUCTION

lunar

is

ma-

material

in more

result

1.

of

sam-

of the up-

The

in 8 kg of lunar

been

monopoles has

and 14 missions.

continued

search

12,

improvement

in Ref.

sections

in the lunar

cross

one used

density

and for

protons.

rays,

the monopole in cosmic

1 for

permits

11,

magnetic The

in Ref. flux

experiment

by the Apollo

negative

derived

returned

still

limits

the monopole

terial

per

for

and the new

ple,

cosmic-ray

as the

and the magnetic

The detector

the same,

independently.

is still

circuit

in a sep-

is repre-

detail

in a superconducting

principle

in an attempt

AI induced

but its

has been modified

46 samples

the ,same into

was

EXPERIMENT

divided

charge

was measured

change

consumption

the magnetic

sample

was

technique

THE

by incident

production

search material g of each

lunar

The

pair

The

charge

to measure on liquid

used

to save

on the current

helium relying

circuit

The

object.

charged

in more

func-

charges,

We

in

change

of a SQUID3

is a periodic

needed.

of undetected

were

distinct

and hence

two

are

detection

there

the domain

escaped

P

N

have

However,

of passes

response

of the noise

the current

consisting

1 and described

magnetometer

now to measure

is used

would

because

coil

that

its

be detected and because

of AI cannot

sensitive

in Fig.

by a magnetically schematically 2 A very

values

to a 1000~turn

report.

traversed sented arate coupled

in the circuit. Certain

signal

numbers

to minimize different

Therefore, with

charge

Np= 1, 2, 4, 8, and 16. of magnetic

a series

tests

of AI.

the magnetometer tion

several used regions

are

sity

shown

on Fig.

Because distributions i),

3. of the correlation

north(as explained

and south-pole

-5-

between produced

denin

6.81

due to the

kg

only

density

are

of them the monopole

pairs for protons,

when the new limit ray

corresponds

and the

selection

12,

That in the

Apollo

1. particles

the 2.02 kg from in Ref. for a

the

exper-

of pair

for

sam-

1 mm

section recent

for

still

4.

assumed

are

search;

to search

one.

magproduction

for

and (b) mentioned

they

in Fig.

monopoles

than is then for

2.0 x iOd4

density limits

by our

the properties

shown

the cross

upper set by other

techniques

detection

IV) we listed their

are

limits

of less

Our

using

cosmic

14 materials,

limit

11 analyzed

level. with different

comparable

The maximum

size

Apollo

Apollo

by incident

we compute

Ref. production from

pair of fines 7.9 kg from

used.

to an arbitrary ples 95% confidence along

7-9 using

production iments 1 (Table condition are

place

the restrictions(a)

there

CONCLUSION desirable

on their

a single

charge.

The

can be heldout

mono-

theory

isolated

20 kg of material.

placed

even

of about that

this

magnetic

the Dirac by its magnetic

with detected

compatible

a way

the analysis

by the limits

was a highly

unambiguously

than

them

of isolated

sensitive

and the hope to detect more

against great,

even

the existence

charge

out in such

4 from

as evidenced

soil

In addition,

that

In Ref.

here.

monopoles valid above.

lunar

monopoles,

The netic

carried

in Fig.

been

of the minimum

was

section search

cross The

have

monopole would

evidence by now very

in experiments

is

accumulated poles only

to thank

-6-

excellent

his

for

Byrns

Taylor

John

Roscoe

Jr.

for

engineering

and sustained

his

and Professor

of our

Lunar

Mike

Re-

and

Eckman

Edmond

from

Dr.

the

support

Annexstad,

the work

brought

Bean,

Michael

who

Alan

Jr.,

without

John

of the experiment,

Galik,

and Glenn

to the design

detector,

experiment,

ACKNOWLEDGMENTS We wish

of this

of our

contributions Maurilio

decisive we thank

Leo

the running

his

and construction

support in the design

technical talent

Vant-Hull

support,

during

Antuna,

help

For

Benedict for

help.

Foley,

technical

in particular

E.

Mitchell

Jr.,

Aldrin,

Edwin

Gordon,

D.

F.

been possible

Westover. not have

Brock would

and

we thank

experiment

Villarreal,

for

Smith

technical

In addition

for

Lorin

Leo

Laboratory

Hagopian

and Phil

valuable

SQUID. for Lee, Hagop ceiving Duke,

This

Armstrong,

A.

Neil

Jr.,

and Edgar

Richard

Conrad,

Roosa, analyzed.

A.

Charles

of the astronauts Collins, B.

samples

Stuart

Alan

the lunar

Shepard, back

-8-

A.8Jaug

‘s

‘n saJuaza3ax

~?UIO$V

‘9088-6VSVN

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10100.2

35.50

10057 10045.18 10002.22 10053.1

R R R R It R

'R R R R R R

Ii H R R R R

11.

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-.02

.06

‘brie, s

=F stands for fine material of grain size less than 1 mm, R stands for rocks and chips. b The units of gmeas are go [see Eq.(i)].

34

39.74 49.13 34-4.76

10019.31 29.66 10058.3 173.29 10085 .iui~ 26.03 10061.48 27.00

33

10044.15 10082.1

10072.19 40.26 10017.74 107.52 10021.36 29.98 10061.2 32.89 10017.81 98.98 ioo8y.i~ 28.13 3m

Q&

Apollo

Weight w

II.

32

NASA Sample Number Number -

Table

pue sy30.1 .I03 spuey3 x

40’ LO’

80’

00’

0-C’

upx8

*[(t)*b3 ‘UIUI 5 ueyzJ ssa1 aqs

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Ozlaxe seau.I 2 30 squn dB

aq;~~

30 ~E!~.Ia~eux au73 JO3 spue$s

91’91 $3 ‘OT 08.

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Figure Fig.

1.

Sample

path

magnetic sured

charge by the

SQUID. Fig.

2.

3.

Fig.

4.

coupling

limit

from

Upper

of a 1000-turn

used

change

field

coil

for

is meato the

as determined

limit

work,

determined B

B

level)

section

in recent from

1 through

Ref.

on the flux

in recent from

(95y0 confidence cross

of samples

46

III.

(95% confidence

this

production

work,

loop

Current

measurements

I through

monopoles A

superconducting

measurement.

Magnetic-charge

Upper

the

2

of Tables Fig.

through

Captions

Ref. level)

monopole 7,

C

7, C from

searches.

from

Ref.

on monopole

in proton-nucleon

monopole

of cosmic

8,

pair

-

collisions

searches. Ref.

8.

A D

from from

as this Ref.

9.

G: WI ti

sI

P C

Magnetic

charge

00O 0 0 000 0 0 I-

I

(Dirac unit ,+=north)

-15-

C B I

A

Lorger

N (Cl

IO2 Monopole

IO4 kinetic

IO6 energy

IO8 (GeV)

IO’O XBL733

Fig.

3

- 2559

____.--. -^-.~..-.--_.--._.._.____---.-----

~______--~_._~_---..

-----.-

--

I

Upper limits on pair-production cross section (95% confidence) (pb) G& 0, 0, 1 0, 73, 51 0, 03 P