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Type 2 Supernova. Blue Giant star. J. van der Velde University of Michigan 2 April. 2007. After (only) 1 million yrs…. Shell supported by pressure of nuclear fusion burning. Core Collapse (~ 1 sec). Rebound. 10 55 neutrinos. You. Me. The last two nearby ones were in 1604 and 1572.

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type 2 supernova
Type 2 Supernova

Blue Giant star

J. van der Velde

University of Michigan

2 April. 2007

after only 1 million yrs
After (only) 1 million yrs…..

Shell supported by pressure of nuclear fusion burning







which brings us to imb
Which brings us to IMB….

170,000 years ago a large star, Sandulek, in the Large Magellanic Cloud, underwent gravitational collapse, sending a 10-second wide pulse of neutrinos out into the Universe. This pulse hit the Earth on 23 February, 1987, around UT 04:00, when 3X10**15 neutrinos went through the IMB detector.

Six months before, the detector had been upgraded to increase it's photocathode coverage by a factor of four. This gave it just enough sensitivity to record eight neutrino events.



Supernova 1987a

A History

Of Dumb Luck ?


Intelligent Design?

tokyo august 1978
Tokyo, August 1978
  • The story begins here:

XIX th International Conference on

High Energy Physics

  • Actually it began 170,020 years ago

in the Large Magelanic Cloud, when humans were still

gnawing on bones. They couldn’t even talk let alone

do powerpoint ……..

Let’s listen in back then, using top-secret

“Blue Cloud” technology……..


G: Hairy creatures on Earth are starting to show signs of intelligence. In 170,000 years they will have Proton Decay detectors.

g: They’ll never find PDK, as you know.

Their detectors are 1000 times too small.

But what can you expect?

Their brains are not made of Silicon.

They’re made of meat!


G: Yes, too bad. Let’s be nice and send them some supernova neutrinos to appease their funding agencies.

g: How about Sandulek in the LMC?

G: go for it !

jump ahead august 1978
Jump ahead… August, 1978
  • The Tokyo conference was all a-buzz with Grand Unification Theories
  • “Minimal” SU5 was predicting a proton lifetime of 1029 years for the mode

p e+ π0

Planes leaving Tokyo were filled with strange characters holding little books and making weird scratches on paper napkins, like….

6 02 x 10 26 protons kg
6.02 X 1026 protons/Kg

This is not a small number

compared to 1029 years

Make that 6 X 1029 protons/tonne

……gives 6 decays per tonne per year!

Hmmm….that’s only a cubic meter of water

pre history
  • 1925, Hermann Weyl:

“ Why doesn’t P+e photons ?”

  • 1938, E.C.G.Stueckelberg and (1949)E.P. Wigner :

“That’s easy there’s something called Baryon Number which is conserved !”

OK, but why not look?

1954, Reines, Cowan, and Goldhaber:

t >1022 years (Phys Rev 96, 1157)

1960 Backenstoss et al. (Nuovo Cimento 16 749)

t> 1026years

1974, Reines and Crouch: (Phys Rev Lett 32 493)

t > 1030 years (for modes with muon)

1978 fall flurry of activity
1978 Fall Flurry of Activity
  • Brookhaven, Irvine, Harvard, Imperial College, Michigan, Oxford, Purdue, Wisconsin….…
  • For IMB the dust settled in January ’79.

A meeting at Irvine signed up:

W. Kropp, J. Learned, R. March, F. Reines, J. Schultz,

D. Sinclair, H. Sobel, L. Sulak, J. van der Velde.

M. Goldhaber was soon added and letters of support were solicited from Glashow, Gell-Mann, Salam and Weinberg.

relegated to the appendix a paragraph about possible supernova detection
Relegated to the appendix, a paragraph about possible supernova detection:

“While insensitive to neutrinos below about 50 MeV, [the detector] would give excellent data on the spectrum above this energy and perhaps (uniquely) indicate [the suprnova] source direction.”

If their brains were made of Silicon they would have put this up front,

not in an appendix


“That was a motley crew….

I wonder if they’ll amount to anything ?”

28 november 79 big day
28 November ’79… Big Day!
  • Official approval from D.O.E.
  • Dosco machine starts digging
28 november 79 big day1
28 November ’79… Big Day!
  • Official approval from D.O.E.
  • Dosco machine starts digging
  • 2400 five-inch PMT’s ordered from EMI


  • …. One year of salt dust, construction,

plumbing, and other grub work


  • September 1980….

Digging finished!

  • Schlegel Co. is engaged to install plastic liner
spring of 81
Spring of ‘81

G: The neutrino pulse is fast approaching…

What’s going on?

g: IMB is funded but their PM tubes are too small. Their proposal said they would need an electronics upgrade to detect supernova neutrinos.

Kamiokande is thinking much bigger tubes.

G: Good for them.

They must know about

Intelligent Design

December ‘81

Cosmic ray muon

signals look good

in 10 ft of water

Yes, it really works…. Nice and clean

20 january 1982
20 January 1982

Water depth = 13 ft.

Larger leaks develop

The pool is MT’d

We need a better plan

Something smooth to support the liner against the water pressure

Something that doesn’t dissolve salt !

the answer
The Answer

Use low density (ρ = 1) concrete

Pour it in while filling with water

Do it in stages to let it harden

May, ’82

Dan gives schedule: “Full by August”

may 1982
May 1982

We have some time to think…

Idea: (revival)

How about installing that hardware which would possibly enable us to see a supernova explosion in our galaxy?


G: Hey, are those IMB characters getting our messages?

The SN1987A neutrinos are

99.997% of the way there !

  • Bethe estimates ≤ one SN /30 years
  • Essentially all of the signal would be below our threshold

Let’s put it on the Back Burner

G: Who is Bethe?

july 31 1982
July 31, 1982

The pool is full: 70 ft, no leaks

Reports from Paris ICRC meeting:

Soudan-1, NUSEX, KGF are finding


We start taking data (slowly)

october 7 1982
October 7, 1982

10 million triggers

20 contained events

Any candidates for PDK ?

check opening angle
Check opening angle

Opening angle = 135 deg

(Should be 150-180)

  • Total energy ?

1230 MeV

(Should be ≤ 1100)

Muon decay ?

slow time scale window
Slow time scale window

Clear evidence

for muon decay

Cancel that call to the NY Times

january 83
January ‘83

First public report:

80 days of live time

No candidates for P e+π0

t/b ≥ 5 X 1031 yr

spring of 83 the theorists regroup
Spring of ’83the theorists regroup…

“How about µ+k0 …… etc ?”

May ’83…. Kamiokande taking data

We need more light collection !

G: Uhhhh…. No kidding !

july 83
July ‘83
  • Set limit on PDK to (µ+ k0 )… ≥ 1031 yr
  • Set limits on Monopole Catalysis of PDK
september 83
September ‘83
  • Upgrade proposal presented to D.O.E.

8-inch Hamamatsu PMT’s imbedded in wave

shifter plates 4X light collection ($1.7 M)

  • April ’84: D.O.E. agrees to $1.5 M, spread out over 3 years. We order 8-inch tubes from Hamamatsu.
  • Meanwhile we are installing wave shifters on our 5-inch tubes… = “IMB-2”

(Still not much good for SN’s)

G: These people are running out of time !

january 85
January ‘85
  • “Big List” of limits on 34

decay modes of nucleons published in PRL.

Nine “candidates” could be various off-beat modes, but all are consistent with neutrino background, e.g…..

event 663 1770
Event 663-1770

This is a candidate for neutron decay into e+π-

But it could also be a cosmic ray neutrino interaction.

“The value of a candidate depends on his background”

……Maurice Goldhaber


A tough time for theorists…

American Way, July, 1983

october 86
October ‘86

We now have four times the

Light collection of IMB-1

At a collaboration meeting Eric Shumard revives (again) the idea to upgrade our data acquisition system to facilitate automatic supernova detection.

Decision: No $$$, No time, No urgency

Rule #One: Listen to your graduate students !

february 23 1987 ut 02 30
February 23, 1987UT 02:30

A Few Months Later….

G: Neutrinos just passed Pluto

What’s going on?

g: Every one is asleep.

ut 05 00
UT 05:00

G: the neutrino pulse is just passing Saturn.

What gives at IMB?

g: Detector on auto…Nobody there,

no supernova alert system in place.

G: Punish them!

ut 05 00 00 001
UT 05:00:00.001

One of four HV power supplies

shuts down at IMB.

On-line data analysis system shuts down.

Detector limps ahead with ¾ tubes

and raw data tapes only

Two hours later…….

ut 07 35 41
UT 07:35:41

Thirty thousand trillion neutrinos

pass through the IMB detector

Only 8 are left behind

the rest is history
The rest is history….

It took us a while to dig out these events

from the raw data tape, but once we did

the signal was dramatic.

  • The normal rate of similar events is

one every 5 days.

  • From random probability, 8 such events in 6 sec will occur:

Once every 2X1034 years !


G: It’s not a coincidence…

Gabi, have you been playing with the numbers again?

g: I cannot tell a lie Boss…

I installed a string theory with proton lifetime = 2.137 X 1034 years

What a crazy coincidence…

That’s just a little greater than

the lifetime limits on the proton!

the data
The Data

Phys Rev D37 3361 (1988)

We’ll hear a lot more

in the next three days about the nice things

we have learned from the SN1987a data.

We sure would like to see another one!

There’s a lot more to be learned,

Including clearing up some mysteries like…

Hint, hint


Hopefully, that will be accomplished by

some of you intelligent designers in the audience!


g: “Boss, There’s a lot of physicists down there that still don’t believe in

Intelligent Design.

Maybe they need another BigLuckyBreak to convince them.”

G: “Send ‘em to Hawaii !”