Cerenkov counter telescope for monopoles producing straight lightning stroke

Tompkins, D. R.

English

NASA Technical Reports Server

Pr inc ipa l  Invcs  t i  g a  t o r  
J ~ i l y ,  1970 
https://ntrs.nasa.gov/search.jsp?R=19700026275 2020-03-11T23:39:21+00:00Z
P 
Abst rac t  
The present  ourtlool; f o r  nonopofes  i s  tba t  they rre 
e i t h e r  a)nonexis tant  b) extrenely rnre or  c)l:ave unexpected 
p r o p e r t i e s ,  A Cerenkov countm te lcscope  wi91 soon be i n  
o?>era t ion  t o  i n i t i a l l y  seel- rononoles of cata~gory c s  The 
instr1:mentxtion of t h i s  t e l e scope  is  e s s e n t i a l l y  a s  descr5bed 
i n  e a r l i e r  proposals ,  It i - n s  been proposed t h a t  r e l z t i v i s t i c  
monopoles may produce straifr’ri t  1 i gh tn ing  s t rokes ,  A d e t a i l e d  
d i scuss ion  o f  this is  given i n  t h e  p r e p r i n t  W o u l d  R e l a t i v i s t i c  
Monopoles Produce S t r a i g h t  Lir l i tn i i ig  Strokes?!, Based on t h i s  
(cita::ory b) a sePrC 11 i s  underway using Smithsonian Astrophysical  
n ight  sky photography of l i gh tn ing ,  Appeiidix A con ta ins  a 
p r e s s  re lease and Science New r e p o r t  on a po r t ion  of this 
programe 
2 
Progress Report 
It is curious t h a t  t heo re t i cz f  and some i n d i r e c t  experi- 
mental results lend. evei- more favor  t o  t h e  ex is tance  of 
monopoles while more o r  l e s s  d i r e c t  expc r inen ta l  t e s t s  push 
the monopole flux l i m i t s  t o  steadily smaller values* On  t h e  
favorable  side r ecen t  y e a r s  1-zve broiight the advance of a 
cons i s t en t  quantum e l e c t r o d y n ~ m i c s  r t 7 i t h  monopoles by Schwinger 
and t h e  observation of t h e  lack of C,P, invar iance2  which  has 
1 
resi .f l ted i n  tile cons t rnc t ion  of elementary p a r t i c l e  models 
based on monopolese 39 4 On the s t r i c t e r  limits side we haTe 
7 
5 9  Alvarez e t  a 1  t h e  experimental  r e s u l t s  of F l e i sche r  - e t - 9  a9 --
and the r ecen t  primary monopole flilx limits from Osborne's 
pepcre8 T h i s  narrows the  s i t i : n t i o n  down t o  t h r e e  p o s s i b l e  
conclcsions:  (a)monopoles do not  e x i s t  ( a  conclusion which  i s  
s t e a d i l y  l o s i n g  ground among t h c o r e t i c ~ J .  p h y s i c i s t s )  (b)monopoles' 
a r e  extremely r a r e  o r  (c)monopnles do not have a l l  t h e  p r o p e r t i e s  
we expect ,  We d i s c u s s  the i-clp.v;Lnce of (b) and (c) t o  t h i s  
experimental  program 
If  nonopolcs a r e  as r a r e  ns present experimental  l i m i t s  
I n d i c a t e  then geometry is a prime r eq r l i s i t e  €or nny cosmic raj7, 
method of searching f o r  norm poles^ To some ex ten t  this groups 
e f f o r t s  hc?ve been based on Ceren1:ov col-nter methods and a dual. 
Cerenkov counter  te lescope  i s  j u s t  now nearing complete i n s t r n -  
mentation, Unfortunately the expe r inen ta l  l i m i t s  a r e  now too  
small  f o r  Cerenkov counter  ricthods t o  be e f fec t ive  f o r  primary 
3 
monopolese One simply cannot ;.chieve the  required geometry, 
Replizing this t h e  p r i n c i p a l  i n v e s t i g a t o r  sotlght and found 
two new l a r s e  Geometry methods, 9 y  lo One of t h e s e  methods 
wor:Id search  €or h i g h  a l t i t v .de  knock-on e l e c t r o n  showers which 
would be c h a r a c t e r i s t i c  of primary cosmic r ay  monopoles wi t11  2 
very l a r - e  ma-nctic chFrre,  
very recent  linits (s t lbjcct  t o  sone unce r t a in ty )  on primary 
monopolesS un le s s  t h e  mono9oles have z r e s t  mass which is 
unbelicvnbly l a r g e ,  Tlie othcr method i s  t o  look f o r  s t r a i g h t  
l i g h t n i n g  s t r o k e s  which would Se c h a r a c t e r i s t i c  of cosmic ray  
monopoleso This method a p p l i e s  t o  both primary and secondary 
monopolcs of a11 allowed ningne-tic cLarge values. T h i s  method 
T h i s  rietl~lod i s  ec l ipsed  by Osborne*s 
has an extremely Pzrge gcornetry w ~ i c i i  c;n, f o r  l a r g e  r e s t  mass 
v d u e s ,  even compete w i t h  Ost:orneg 5 l i m i t s ,  A l s o  t h i s  method 
can set new monopole production c ros s - sec t ion  l i m i t s ,  The 
Smithsonian Astropliysicaf Observatory has  opercted a system of 
sky  photoyrophy s t a t i o n s  for s i x  y e a r s  and i s  makins f o u r  years  
of b-c!- f i l m  (as wll  as ciIxrri2t l i@l i tn ing  pliotoTraphs) a v a i l a b l e  
i‘cr a n a l y s i s ,  T21is f i lm  w i l l  e i t h e r  f i n d  rioEo!>oles o r  s e t  new 
linits on both moRoi’ole prod.1.c-t i o n  cl-oss-sections and on the  
f l . 1 : ~  of r izssive p r ina ry  monopoles, 
I f  noropole  p r o p e r t i e s  a r e  no t  what v e  expect then  where 
i s  t h e  e r ror?  
be a 1 -n ivc r sa l  p roper ty  of t h e  e lectromagnet ic  f i e l d  and so i s  
Schwinger h ~ s  argried t h a t  renormalizat ion s!ionld 
t h e  same f o r  monopoles as f o r  e lec t xozsB ,  T h i s  COnCl~~Sion is 
c o n s i s t e n t ,  i n  a simple way, v i t h  m-gnct ic  charge Guantization 
condi t i r  zse 
4 
11 
Except f o r  this group's erzrfier experinelit no sexrches 
h?.ve been condilctecd f o r  monoywles n e a  n i n i m u m  i o n i z a t i o n  
(ox7er-rcno.rm?vs i z c d  nonopoles)  a 
t h e  Ccrcnlrov counter  te lescope i s  t o  conduct i! mi:cli more 
The f i r s t  use ice v d I l  make of 
extcnsive search  f o r  such rionopoles i n  cosmic r ayse  
F i i l n l f y  ::e no te  t i i ~ ~ - t  n3ny c u r r e n t  experimental restrats 
depend s t r o n g l y  on tlie conservation of m g n e t i c  chargcl, No 
t h e o r e t i c 7 1  o r  cxpcr inenta l  reorl- has sc r io r l s ly  questioned t h i s  
property and we s e e  no re?son to do so4, I-Torcever i t  m i ! s t  be 
n o t e d  t ha t  Osborne$s r c s i i l t  2s w e l l  9s t h e  t rapping  experiments 
r e w i r e  a magnetic charge l i f e t i m e  of a t  l e a s t  10 
the nonopole t r ack  worl- of F l e i schc r  et al r equ i r e s  a f i f e t i m e  , 
of a t  l e a s t  I O a 4  s e c  ( a s  a l s o  does t h e  nonopofe l i g h t n i n g  method), 
5 years  while  
6 
-_. 
An estensior ,  of the Cercmj ov counter  method has been proposed 12 
w h i c h  tvoi!ld make i t  p o s s i b l e  t o  i d e n t i f y  monopoles wi th  a l i f e t i m e  
as s h o r t  a s  IO--l4/y sec l  No otPlcr rrethod can approach t h i s  
n c c e l e r r t o r  beam, This nictilod c21so nnltes i t  poss ib l e  t o  search  
f o r  nonopole production in very t h i c k  tn rgc ts ,  A modest e f f o r t  
using underground cosmic r a y s  coillcl in . -es t igate  a c ross -sec t ion  
of cm2 pe r  year of d a t a  fop. t h e  prodtiction of monopoles 
by muons above IO3 BeV, This would n o t  se t  new cross-sec t ion  
l i m i t s  and so is  n o t  a planned experiment, 
5 
R c E c s en r. c s 
1, 
2, 
3 ,  
4, 
5 .  
6, 
7, 
8 ,  
9 ,  
IO B, 
kexrcl Cnsnic Rn37 Search f o r  
Appendix A 
T h e  paper of D. R. Tornpkins, B u l l  Am. Phys. SOC. - 15,  39 
( 1 9 7 0 ) ;  w a s  s e l e c t e d  f o r  a Gzess release by t h e  American I n s t i t u t e  
of Physics.  Subsequently a . b r i e f  r e p o r t  appeared i n  Science 
N e w s  - 97 ,  151 ( 1 9 7 0 ) .  A copy of the  p re s s  release and a page 
copy from Science N e w s  are presented i n  t h i s  appendix. 
N E W S  F R O l V  T H E  A A I E R I C : A N  I N ' i T i T u T E  O F  P I I Y S I C S  
3 3 5  E A S T  4 5  S T R E E T .  N E \ V  Y O R K  1 0 0 1 7  ( 2 1 2 )  6 8 5 - 1 9 1 0  
0 1  I'Icr 0 1 '  I 'UBI. lC R I  1 A T I O N S  FROM: PRESS ROOM, JOINT MEETING O F  
THE AMERICAN PHYSICAL SOCIETY and the 
X b D R C Y  .JiRI\ISTRONG, Arsistatit Director AMERICAN ASSOCIATION OF PHYSICS TEACHERS 
Private Dining R o o m s  7 & '8  
Palmer House, Chicago, I l l i no i s  
Telephone: (312) RA 6-7500 
Meeting Date: 26-29 January 1970 
RELEASED F O R  TUESDAY MORNING, JANUARY 27, 1969 
Author's Popular Version sf  Paper: BE-8 
"WOULD RELATIVISTIC MONOPOLES PRODUCE STRAIGHT LIGHTNING STROKES?" 
Presented by: D .  R .  Tompkins 
University of Georgia 
Athens, Georgia 
Alember Societies: American Physical Society 0 O{ilirrrl Society of Anierica 9 Acoustical Society of America s Society of Rheology 
Arnericati Association of Physics Teachers 0 American Crystallographic Association Anzericatl Astronotnical Society 
Would'Cosmic Ray P bes ce S t r a i g h t  L. i ing Strokes? t 
malc Tompkins 
.iysi. Jepartment 
l ive y of Georgia 
the i eorg ia  30601 
It  i s  we11 3wn t l  c u t t i n g  a n e t  i n  :.f does no t  
r e s u l t  i n  "ha l f  ck~fnet u t  rather :wo magr. e I f  w e  
r e a l l y  could i t on nd of a m a  w e  woult we a magnetic 
monopole (an i 14 2d I; tetic char$ The POSE l i t y  of the 
ex i s t ance  of n ' a m e  1 p a r t i c l e  
charge (a mo -e) i: le of t h e  fi 
physics  t o d a .  W e  kr t h a t  rnonop 
mul t ip l e s  oa. *.m elm iry u n i t  of 
monopale would i n  .qx% very stror: 
i n t e n s e  t r a i l  of G n s  (electrical: 
z 
knocking away at-wic e l e c t r o n s )  e 
must s u r e l y  be p resen t  among t h e  
it is  shown t h a t  a t r a i l  of ions  
charged, cosmic ray  monopole may 
l i g h t n i n g  s t roke .  
The b r i g h t  s t r o k e  observed as 
preceeded by a dark s t r o k e  called a 
4ng  an is0 d magnetic 
i n t e r e s t i n !  cets of 
; could only ?t as 
qnet ic  chargc 11 f a s t  
wi th  matter and l eave  an 
harged atoms obta ined  by 
monopoles can e x i s t  then they 
ticles of cosmic rays .  H e r e  
n a f a s t ,  heavy, mu l t ip ly  
ult i n  a very s t r a i g h t  
ord inary  l i gh tn ing  i s  a c t u a l l y  
s t e p  leader:. The s t e p  leader 
1 
advances from t h e  cloud toward khe ground i n  a series of s t e p s  
sepa ra t ed  by pauses.  This  LeadQr i s  found t o  change d i r e c t i o n  a t  
',Supported by t h e  Nat iona l  Aeronaut ics  and Space Administratio;  
g r a n t  NGR-11-00 3-0 2 1  
I 
- 2 -  
each s t e p  and t h i s  causes t h e  crooked shape of t h e ' , r e s u l t i n g  
r e t u r n  s t roke .  The b r i g h t  r e t u r n  s t r o k e  follows t h e  pa th  of t h e  
s t e p  leader and goes upward from ground t o  cloud. Mul t ip le  
s t rokes  are common and i f  these occur wi th in  no more than  one 
t e n t h  of a second then  they  occur i n  t h e  previous r e t u r n  stroke 
channel. Such subsequent r e t u r n  s t r o k e s  are immediately preceeded 
by a da r t  r a t h e r  t h a n  s tepped l eade r .  The d a r t  l e a d e r  i s  dark 
and i s  only  as s t r a i g h t  as the  r e t u r n  s t r o k e  i o n  channel which 
it fol lows,  I f  t h e  previous r e t u r n  s t r o k e  channel is "old" t h e  
I 
dart  l e a d e r  may change i n t o  a s tepped l e a d e r  as it nea r s  ground 
level.  . 
I n  o r d e r  f o r  a monopole t o  p e n e t r a t e  t h e  whole atmosphere 
and y e t  remain f a s t  it must have a l a r g e  i n i t i a l  energy and 
be a t  least  several hundred. t i m e s  more massive than  any 
elementary p a r t i c l e  now known. Such a monopole (with m u l t i p l e  
u n i t s  of magnetic charge) may. leave  a t r a i l  of i o n i z a t i o n  whose 
d e n s i t y  i s  comparable t o  t h a t  p r e s e n t  i n  an "old" r e t u r n  s t r o k e  
channel immediately p r i o r  t o  a d a r t  l eade r .  Unlike a r e t u r n  
s t r o k e  channel t h i s  i o n i z a t i o n  t r a i l ' w o u l d  be q u i t e  s t r a i g h t .  
Because t h e  i o n i z a t i o n  t r a i l  of a f a s t  monopole would be  comparable 
t o  an "old" r a t h e r  t han  "young" r e t u r n  stroke channel w e  should 
.expect a s t r a i g h t  dar t  leader t o  o f t e n  change i n t o  a s tepped 
leader near  ground level.. Thus s t r a i g h t  l i g h t n i n g  may o f t e n  appear 
as ord inary  l i g h t n i n g  wi th  a long s t r a i g h t  upper segment. Before 
w e  can have l i g h t n i n g  w e  must have a s u f f i c i e n t l y  high voltage 
between cloud and ground, D o  thunderclouds main ta in  high 
P 
' *  
* i  
- 3 -  
vol tages  over  s i g n i f i c a n t  areas for apprec iab le  l eng ths  of t ime? 
An a f f i rma t ive  answer i s  provided by the occas iona l  observa t ion  
of l i gh tn ing  a r t i f i c a l l y  induced by water plumes from depth 
charge explosions.  
F i n a l l y  w e  must ask  i f  t h e r e  a r e  o the r  poss ib l e  causes of 
s t r a i g h t  l i gh tn ing?  Very high energy cosmic r ays  gene ra t e  a 
cascade of p a r t ' i c l e  c o l l i s i o n s  i n  t h e  atmosphere. I n  t h e  
. r e s u l t i n g  "shower" t h e  t o t a l  number of p a r t i c l e s  reaching  t h e  
earth may exceed a b i l l i o n  and be spread  o u t  over an area of 
square k i lometers .  The ''core'' of such a shower i s  narrow and 
conta ins  t h e  g r e a t e s t  p a r t i c l e  dens i ty ,  I t  tu rns  o u t  t h a t  i n  
I even t h e  l a r g e s t  showers t h e  p a r t i c l e  dens i ty  i n  t h e  co re  does 
no t  approach that  be l i eved  necessary for a d a r t  l eader .  
air  shower cores  are n o t  a l i k e l y  source of s t r a i g h t  l i gh tn ing .  
Thus 
Because of unc ,e rka in t ies  i n  q u a n t i t a t i v e  p rope r t i e s  of 
l i gh tn ing  i t s e l f  w e  cannot draw negat ive  conclusions about 
monopoles from f a i l u r e  t o  observe s t r a i g h t  l i gh tn ing .  
However w e  can hope t o  ga in  a h i n t  about monopoles by a c t u a l l y  
see ing  o r  photographing such s t r o k e s e  
. 
f 
Fig. 1, . Likely Appearance of Straight Lightning 
Gathered at the 1970 anrrsuas meeting of the 
mevican PgPysicaB Society in Chicago last week 
ATOMIC PHYSICS 
easlmring the magnetic mo 
Much of the great success physicists have had in un- 
derstanding the workings of atoms has come by mcasur- 
ing the strengths, or energies, of various interactions 
that take place within them. One of the most important 
is the interaction between spinning charged particlcs. 
A spinning ball of charge acts like a tiny elcctro- 
magnet, the strength of which is known as its magnetic 
moment. 
Four scientists from the Massachusetts Institute of 
Technology, Drs. P. F. Winkler, E. G. Walther, M. T. 
Myint and D. Kleppner, report that they have measured 
the ratio of the electron and protdn magnetic moments 
more precisely than has been done before-to an accu- 
racy of one part in 100 million. The figure they obtained 
for the ratio is 658.210705 2 .00@306. 
Their precise measurement of &e of nature's funda- 
mental constants may increase knowledge of other oncs, 
say the scientists, like a crossword puzzle in which filling 
in the letters of cone word oan help, complete the spaces 
for other words. 
ASTRONOMY 
er look at gam 
a kev to a th ory uniting the strong and el ctromagnetic 
forces, could explain the structure of neutrons and pro- 
tons and help solve the puzzles of nuclear structure. 
Recently the theory has been under fire from experi- 
menters who found results at odds with its predictions 
(SN: 8/30, p. 164), but Dr. Bernard Margolis of Mc- 
Gill University reports that accurate calculation of the 
latest experiments supports the theory. The shadows of 
various nuclei that a photon beam casts come out cor- 
rectly, he says, if one assumes that photons turn to vector 
mesons as they interact with nuclei and then turn back 
to photons. 
LOW TEMPERATURE PHYSICS 
HeEium mollecaases i 1 
When liquid helium is cooled to temperatures less 
than four degrees above absolute zero it becomes a 
superfluid. That is, it flows without friction, can go 
through holes too small for ordinary fluids, and in cer- 
tain conditions can be induced to flow uphill. 
The key to understanding this beh,avior lies in the 
microscopic structure of the superfluid. Drs. W. A. 
Fitzsimmons, J. W. Keto, M. Stockton and L. J. Smith 
of the University of Wisconsin propose a new experi- 
mental tool for this study. 
Optical experiments show, they say, that neutral he- 
lium molecules, two atoms bound together, the * usual 
constituents of helium gas, also form part of the sub- 
structure of superfluid helium. Ordinarily much more 
dramatic changes could be expected with a change of 
state, and they suggest that following them the appar- 
ently normal bound atoms around in the abnormal state 
will be a useful way of studying the structure of the 
superfluid. 
Last year astronomers discovered the first point source 
of gamma rays, in 'the constellation Sagittarius (SN: 
9/27, p. 277). There had been speculation for a decade 
that certain stars or nebulae might emit this extremely 
energetic radiation. 
The source was located with equipment flown in 
balloons from Parkes, New South Wales. The source is 
directlv overhead in the skv in Australia. 
One' of the members ofathe team that made the dis- 
covery, Dr. Glenn M. Frye Jr. of Case Western Reserve /PARTICLES 
University, reports that - additional balloon flights are 
planned to locate the position of the source more pre- 
cisely. A clock accurate to one part in 100 million will 
be carried along to see if the source is winking on and 
off likethepulsarL,_- . - _ _  
PARTICLES 
A comprehensive theory of subatomic particles will 
have to provide a unified explanation of the different 
classes of forces they respond to. In the hope of getting 
to such a theory physicists study examples of connections 
between different forces such as the behavior of photons 
when tI strike atomic nuclei. 
Photons are carriers of the electromagnetic force, yet 
when they strike nuclei, they behave like vector mesons, 
carriers of the strong nuclear force. 
In explanation of this, a theory called vector meson 
dominance has grown up, which says that, on approching 
the nucleus, the photon turns into a vector meson. If 
such a transformation does in fact happen, it would be 
h e E ~ l ' ~ g b f ~  p+ 19?@ 
A magnetic monopole would be an object that had 
only one pole of magnetic charge instead of the two 
possessed by ordinary magnets. Monopoles have never 
bcen seen, but their hypothetical existence is important 
to basic physical theories, rand they have been searched 
for in almost every conceivable place. 
Dr. D. R. Tompkins of the University of Georgia sug- 
gests another: looking for them in lightning strokes. 
A lightning stroke consists of two movements, a leader 
stroke from the cloud to the earth and a return stroke 
from earth to the cloud. The leader, which is not visible, 
generally follows a stepwise path. It leaves a hail of 
ionized gas behind, and the bright return stroke runs 
back up this path to the cloud. 
Dr. Tompkins points out that a magnetic monopole 
passing through the atmosphere would also leave an 
ionized path behind, but it would be straight instead of 
zigzag. Under proper conditions, he thinks, a return 
lightning stroke might follow such a path. This would be 
a clue to the existence of monopoles, he says. 
151 


A cosmic ray search for fast magnetic charges Progress report

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