S S C the S uperconducting S uper C ollider

The early years-SSC The Dawn of Silicon Detector Technology

Special session in honor of Professor Takashi Ohsugi

8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors (HSTD8)

Academia Sinica , Taipei, Taiwan

Dec. 5, 2011Takahiko KONDO (KEK)

2011/12/5 HSTD-8 symposium, T. Kondo 1


S S Cthe Superconducting Super Collider

Once upon a time on the Earth, there was a project called


SSC LHCEnergy 20 + 20 = 40 TeV 7 + 7 = 14 TeV

Luminosity 1033 cm-2s-1 1034 cm-2s-1

MR circumference 87.1 km 26.7 km

Bending field 6.55 T 8.33 T

Dipole magnets 8,652 1,232

Completion 1999, terminated 199820052008Cost $4.4 B >$12 B ~ $10 B

Main accelerator parameters

The cost increase was the major reason of cancellation.


Brief History of SSC

1982: Snowmass workshop

1984: Snowmass workshop, SSC CDG started.

1986: Snowmass workshop

1987: SSC Project approved by President Reagan

1989: Construction started at Waxahachie, Texas

1993: SSC demised in the middle of construction


Snowmass Workshops

Takashi Ohsugi me


The major milestone forward was

Snowmass 1984 [1]

It became clear that all the tracking technique could not work at SSC. Secondary particles in SSC detectors are too dense, too fast and too high in radiation dose. Three proposals for new tracking devices:

1. Straw tubes2. Silicon strip detectors3. Scintillating fibers

[1] Proc. of the 1984 Summer Study on the Design and Utilization of SSC, June 23-July 13, 1984, Snowmass, Colorado


G. Kramberger’s talk at DESY seminar

(2007.9.1)“Towards Radiation Hard Silicon Detectors at SLHC”

page 4

“Silicon strip detectors (near the beam pipe) appear to be limited to…≤ 1032....the 1032 limit could be optimistic.” (PSSC Summary Report pg. 130, 1984)

T. Kondo et al, Radiation Damage Test of Silicon Microstrip Detectors, pg. 612, Snowmass 1984

2007


The prevailing opinion was that silicon vertex detectors were not possible at 1033.

M. Gilchriese’s talk at STD6 Tracking

Workshop(AbeFest), (2006.9.11)

“Silicon Detectors and the SSC”, page 4

This was quoted by Kramberger

1984




“Silicon Detectors and the SSC”, page 6

However, there were indications already in 1984 that Silicon detectors could be more radiation tolerant and that cooling was desirable. (eg. T. Kondo et al.,…

1984


T. Kondo et al, Proc. of the 1984 Summer Study on the Design and Utilization of SSC, June 23-July 13, 1984, Snowmass, Colorado, pp. 612-614

1984

I would be happy if you could refer this paper in your books and review papers in future.

Ra


Radiation Damage Test of Silicon Microstrip Detectors T. Kondo et al., PSSC, Snowmass 1984, pp. 612-614

HPK sensor : 30x30x0.2mm3, strip pitch 0.5 mm, ~10kW

198420

mm

Photo of Radcolor film showing800 GeV proton irradiation profile.

Proton flux vs leak current.Steps due to beam profile changes

from Fig.6 of NIMA270(1988)42


Before (T= 23oC) After 3.5x1014 p/cm2

by 800 GeV protons (T = 7oC)

(1) Silicon is rad-hard (2) little pulse-height change (3) cooling neededI was extremely delighted and excited by this new discovery !!

317 A/cm 102)C5.22(

1984Radiation Damage Test of Silicon Microstrip Detectors T. Kondo et al., PSSC, Snowmass 1984, pp. 612-614




page 10

Report of the Central Tracking Group, pg. 385 Snowmass 1986

…………. Hence, out conclusion is that a silicon microstrip central tracking system is not realistic….

1986


However, there were already indications of full silicon tracking concepts

A Proposal of Solid State Ball for SSC, T. Kondo et al, pg. 399, Snowmass 1986

1986


1988 Radiation damage studies in Japan, Europe and US.Among others, two papers already published in 1988:

Radiation Damage in Silicon Microstrip Detectors, T. Ohsugi, ... T. Kondo, … K. Yamamoto .., Nucl. Instr. Meth. A265(1988)105

eV 20.1

)2

exp()( 2

ef

B

efg

ETk

ETTJ

They got a T dependence of bulk leakage current as

2011A. Chilingarov proposed

at RD50 Workshop, Liverpool, May 2011

eV 206.1efE

23 years later !


1988 Radiation Damage Test of Silicon Multistrip Detectors, M. Nakamura,…T. Kondo, Nucl. Instr. Meth. A270(1988)42 using the irradiated sensor by 800 GeV protons in 1984.

Abstract:……. The effective impurity density decreases with fluence up to ~4x1013/cm2, but for greater fluences, it increases. This may indicate the type conversion of the bulk silicon ………

I think this is the first observation of type conversion in Si strip sensor, I think.


1990 Copy from Gil’s talk at AbeFest


1990

SDC-89-0026

We were extremely optimistic !!

0.25 X0


1992


1993SDC Collaboration meeting at KEK Japan, May 1993


1993SDC Collaboration meeting at KEK Japan, May 1993

….Taka, Akira, Shigeki, Aki, Yasuo, Nobu, Takashi, Youhei, Yorikiyo, Katsuya,…

Moishe

Tom

Larry

John

Harold

Gail

GeorgeGil Dan

Peter

Andris FredBrigg

Michelangelo

Abe

Henry

Dave Ye

Jim


1993Political battles in Japan on SSC


October 21, 1993

THE END

1993


Epilogue 12011

ATLAS Barrel SCT leakage current plot made by me (T. Kondo)

18 years later…See Dave Robinson’s talk for more details


Epilogue 22011 18 years later…

Looking forward to hearing results on Higgs particle searches

at LHC next week !

BBC News (Dec.1, 2011) : “ 'Moment of truth' approaching in Higgs boson hunt “ http://www.bbc.co.uk/news/science-environment-15991392

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S S C the S uperconducting S uper C ollider