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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Blue Giant star
J. van der Velde
University of Michigan
2 April. 2007
Shell supported by pressure of nuclear fusion burning
~ 30 light yrs diam.
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.
Of Dumb Luck ?
XIX th International Conference on
High Energy Physics
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 !
p e+ π0
Planes leaving Tokyo were filled with strange characters holding little books and making weird scratches on paper napkins, like….
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
“ Why doesn’t P+e photons ?”
“That’s easy there’s something called Baryon Number which is conserved !”
1954, Reines, Cowan, and Goldhaber:
t >1022 years (Phys Rev 96, 1157)
1960 Backenstoss et al. (Nuovo Cimento 16 749)
1974, Reines and Crouch: (Phys Rev Lett 32 493)
t > 1030 years (for modes with muon)
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.
“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
I wonder if they’ll amount to anything ?”
plumbing, and other grub work
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
Cosmic ray muon
signals look good
in 10 ft of water
Yes, it really works…. Nice and clean
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 !
Use low density (ρ = 1) concrete
Pour it in while filling with water
Do it in stages to let it harden
Dan gives schedule: “Full by August”
We have some time to think…
How about installing that hardware which would possibly enable us to see a supernova explosion in our galaxy?
The SN1987A neutrinos are
99.997% of the way there !
Let’s put it on the Back Burner
G: Who is Bethe?
The pool is full: 70 ft, no leaks
Reports from Paris ICRC meeting:
Soudan-1, NUSEX, KGF are finding
We start taking data (slowly)
10 million triggers
20 contained events
Any candidates for PDK ?
Opening angle = 135 deg
(Should be 150-180)
(Should be ≤ 1100)
Muon decay ?
for muon decay
Cancel that call to the NY Times
First public report:
80 days of live time
No candidates for P e+π0
t/b ≥ 5 X 1031 yr
“How about µ+k0 …… etc ?”
May ’83…. Kamiokande taking data
We need more light collection !
G: Uhhhh…. No kidding !
8-inch Hamamatsu PMT’s imbedded in wave
shifter plates 4X light collection ($1.7 M)
(Still not much good for SN’s)
G: These people are running out of time !
decay modes of nucleons published in PRL.
Nine “candidates” could be various off-beat modes, but all are consistent with neutrino background, e.g…..
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”
American Way, July, 1983
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 !
A Few Months Later….
G: Neutrinos just passed Pluto
What’s going on?
g: Every one is asleep.
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!
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…….
Thirty thousand trillion neutrinos
pass through the IMB detector
Only 8 are left behind
It took us a while to dig out these events
from the raw data tape, but once we did
the signal was dramatic.
one every 5 days.
Once every 2X1034 years !
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!
Phys Rev D37 3361 (1988)
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…
some of you intelligent designers in the audience!
g: “Boss, There’s a lot of physicists down there that still don’t believe in
Maybe they need another BigLuckyBreak to convince them.”
G: “Send ‘em to Hawaii !”