─юъєьхэЄ тч Є шч ъ¤°р яюшёъютющ ьр°шэ√. └фЁхё юЁшушэры№эюую фюъєьхэЄр : http://zebu.uoregon.edu/~uochep/talks/talks05/DS-SiD.pdf
─рЄр шчьхэхэш : Sat Dec 3 01:52:10 2005
─рЄр шэфхъёшЁютрэш : Tue Oct 2 10:24:05 2012
╩юфшЁютър:

Silicon-tungsten calorimetry and the SiD forward region David Strom University of Oregon

Thanks to Tom Markiewicz(SLAC), Takashi Maruyama (SLAC), Mary Robinson (UO undergrad)

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Intro duction

╖ SiD is a silicon based detector н Silicon pixel vertex detector н Silicon strip tracking for the inner detector н Silicon-tungsten ECAL н Fine grained (RPC?) HCAL

╖ Cost optimization results in a relatively small radius of the inner detector of R 1.25m with large 5 T field

See Snowmass talks from Breidenbach and Weerts
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19 Sept 05 н David Strom н UO

Energy flow drives most of the design Hermeticity is also imp ortant ╖ Pro cesses such as
+- e+e- ~ ~ ~ ~ +0 -0

are tagged using momentum imbalance ╖ Can b e faked by e+e- e+e- + - with missing final state e+ or e- that carry pt

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Quadrant View
8.000 Beam Pipe Ecal 7.000 Hcal Coil 6.000 MT Endcap 5.000 Endcap_Hcal Endcap_Ecal VXD m 4.000 Track Angle Endcap_Trkr_1 3.000 Endcap_Trkr_2 Endcap_Trkr_3 2.000 Endcap_Trkr_4 Endcap_Trkr_5 1.000 Trkr_2 Trkr_3 Trkr_4 0.000 Trkr_5 0.000 2.000 4.000 m 6.000 8.000 Trkr_1

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

BR^2 Fixed, Vary R_Trkr
1000

800

600

400

R_Trkr M$ 200 d$/dR

0 0.00 -200 0.50 1.00 1.50 2.00 2.50

-400

-600

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R_Tr5 r (m) k

19 Sept 05 н David Strom н UO

Bill Cooper's opening scheme (Endcap not split)

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19 Sept 05 н David Strom н UO

Si-W Calorimeter Concept ECAL

Inner Tracker

1.25m

Rolled Tungsten
3.6 Meters 1.1-1.3 Meters

Silicon Wafers

Transverse Segmentation ~5mm 30 Longitudinal Samples 1/2 Energy Resolution ~15%/E
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Polyimide Cables
Layer Assembly

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19 Sept 05 н David Strom н UO

Silicon Concept

╖ Readout each wafer with a single chip ╖ Bump b ond chip to wafer ╖ To first order cost indep endent of pixels /wafer ╖ Hexagonal shap e makes optimal use of Si wafer ╖ Channel count limited by p ower consumption and area of readout end chip ╖ May want different pad layout in forward region

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Silicon Detector Design

╖ DC coupled detectors (avoids bias resistor work) ╖ Two metal layers

net-

╖ Keep Si design as simple as p ossible to reduce cost ╖ Cross talk lo oks small with current electronics design ╖ Trace capacitances (up to 30pF) are bigger than the 5 pF pixel capacitance

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Notes on silicon based calorimetry ╖ For large projects, price dep ends on silicon area (p erhaps 3/cm2)

╖ Ratio of area in a circle to a circle: 3 4

a hexagon inscrib ed square inscrib ed in a 3

3 2

r

r

= 1.29

╖ Ratio of dead edge (e is edge width) space hexagon to square
4 e 3r = 2 2e r

2 = 0.81 3 detectors is

r/ 2

r

╖ Area 2
3 3r 2

of current 118cm2

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

╖ Price of mask set for different shap es is likely a fixed cost of ab out 50K USD. ╖ 50K USD is equivalent to approximately 150 wafers at 3 USD/cm2 ╖ Price could b e reduced if sp ecialized pieces where built in-house. ╖ More than one small piece/wafer may b e p ossible

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Possible endcap layout ╖ Requires 15 different mask sets for zero crossing angle ╖ Nearly twice as many are required if luminosity monitor is offset to b e centered on outgoing b eam ╖ Could rotate silicon pattern 45 on alternate layers ╖ Will need 1cm clearance b etween lumi and endcap.
Barrel ECAL Lumi

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19 Sept 05 н David Strom н UO

Alternative layout
Barrel ECAL Lumi

╖ Radial design allows for radial pads on endcap ╖ Radial design would require at least 13 different masks ╖ Wedges make p o or use of silicon area on a wafer ╖ For an Octagonal outer edge, many more masks needed

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Crossing Angles н Two regimes

╖ Large crossing angle with separate input and exit ap ertures. Minimum angle limited by the magnet size. ╖ Minimum large angle could b e as large as 20 mrad

╖ Small crossing angle with shared input and exit ap ertures. Maximum angle limited by magnet b ore (typically 8-9 cm) ╖ Maximum angle is 2 mrad

For physics zero crossing angle is usually preferred. For machine op eration a large crossing angle is b etter.
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19 Sept 05 н David Strom н UO

Advantages of large crossing angles for machine op eration:

╖ 10% of 10 MW b eam p ower in photons is brought directly to the b eam dump ╖ Input and output b eam optics can b e adjusted with maximum flexibility ╖ Synchrotron radiation from soft b ends in incoming b eam can b e blo cked without interfering with outgoing b eam ╖ Allows for op eration at s > 1 TeV

╖ Allows for small b ore ( 2 cm magnets) ╖ Allows for down-stream instrumentation for determining b eam p olarizations
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19 Sept 05 н David Strom н UO

Disadvantages of small cross angle for machine op eration:

╖ Requires very large b ore magnets for final elements

╖ 2 mrad b end imp oses on CM energy limit from synchrotron radiation

╖ Shared function of magnets leads to less flexibility for the machine

╖ Large amount of energy dissipated in final magnets

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

╖ Snowmass conclusion (Andrei Seryi)

L High Lumi

20 mrad IR
Low ~2W High ~1000 W

vs
High Lumi

L

2 mrad IR
preliminary & qualitative High Very High To be evaluated

Nominal

Very Low <1W

Very Low <1W

Nominal

Low ~1W

Low ~1W

E 500 GeV 1 TeV 500 GeV 1 TeV
(Numbers in Watts show losses on SC FD magnets)

E

FCAL Tel-Aviv University wg4 1st week summary

╖ Optimization of design and evaluation will continue, but clear that disrupted beam losses on SC elements limit performance ╖ Better detector hermeticity & background of 2mrad IR comes together with lower luminosity reach ╖ ( 20mrad IR works well with New High L parameters ) ( 2mrad to be evaluated )
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19 Sept 05 н David Strom н UO Aug 19, 2005

╖ SiD designed to accommo date a 20 mrad crossing angle

Si D Forward Masking, Calorimetry & Tracking 2005-09-15 20mrad, L*=3.51m
E HCAL C A L Muon Yoke

QD0

SD0

QF1

CRAB Lo-Z

BeamCal LumCal Q-EXT

Support Tube
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19 Sept 05 н David Strom н UO

Probably b est to center luminosity monitor on outgoing b eam
Vertical 1:5 Horizontal 1:25
0.25

0.2

0.15

0.1

0.05

0

-0.05

-0.1

-0.15

-0.2

-0.25 0 2

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19 Sept 05 н David Strom н UO

How do es a kink in the solenoid effect the background?
100 20 mrad + DID 20 mrad 2 mrad 80 20 mrad + Kink solenoid pointing incomin beam 20 mrad + Kink solenoid pointing outgoing beam

Energy in BEAMCAL (TeV)

60

40

Energy In BeamCal (TeV)
20

0 0.0 0.5 1.0 1.5 2.0 2.5 3.0

Beampipe Radius (cm)
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19 Sept 05 н David Strom н UO

╖ Detail showing clearance b etween lumi and endcap. ╖ Note that HCAL is centered on the detector axis. ╖ Some electrons will b e tagged by the HCAL ╖ Must supp ort luminosity monitor with a minimum of material outside of detector
17.4 cm

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19 Sept 05 н David Strom н UO

Lumi Detector Geometry ╖ It is essential to survey the detector at the micron level with cosmic ray muons or test b eam. Electronics must have MIP sensitivity even if it is not needed by the luminosity measurement MIP sensitivity needed for p ossible muon veto (See Graham Wilson's Calorimeter talk). ╖ Detectors should fit on a single wafer
8 inch wafer

╖ SiD geometry Rmin 8.7 cm ( 50mrad) Rmax 24.7 cm( 150mrad) 8 inch wafers would b e needed

64 radial pads

Moliere Radius

╖ Rate at 500 GeV is 8 bhabhas bunch train н Inner radius could b e much larger and 6 inch wafers used
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19 Sept 05 н David Strom н UO

Electronics ╖ The ECAL electronics (Kpics) have chips with 1024 channels and store up to 4 hits/bunch train:

reset 10 pF 0.5 pF

Threshold 1

+ -

reset holdoff x4

1V

+ -

digital memory

Scale Select (1 bit)

Detector
Charge Amplifier

shaper analog memory Charge (12 bits)

+Bias

Threshold 2 beam crossing counter

+ digital memory 13

beam crossing (13 bits)

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

A note on a shaping times ╖ For the ECAL calorimeter, maximum leakage current from radiation is exp ected to b e < 10nA. Gives negligible contribution to noise (< 500 electrons) ╖ In the lumi-detector, this numb er could b e a factor of 30 higher or more. ╖ At 300nA, 1 ╡s integration, shot noise is 1400 electrons. ╖ A shorter shaping time may b e needed.

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

╖ Calorimeter of buffers for capacitors for same area as

approach could b e extended to include a large numb er each channel, e.g. 128 Channels Chip each with 128 storing charges for up to 128 bunches would fit into the is presently used for the calorimeter:

Single Cell Layout
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19 Sept 05 н David Strom н UO

╖ A more likely scenario would b e to readout every bunch crossing. This would require a different digitization technique, either SAR or a pip elined ADC with 12 stages. 128 channels would probably fit into the space presently used by the 1024 ╖ Assume Successive Approximation ADC with 12 bits + range, digitizing at 3MHz (internal clo ck is 36MHz). Data rate is 576 MBytes/s/chip during bunch train ( 3.0MBytes/s sustained) ╖ On-detector electronics cost will b e dominated by development costs (very similar to run needed for test b eam) ╖ Won't save much money by reducing channels/wafer ╖ Power consumption should b e reasonable, but no design yet for co oling in the endcap in SiD. LDC will b e easier.

FCAL Tel-Aviv University

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19 Sept 05 н David Strom н UO

Conclusion ╖ SiD thinking ab out forward region is in very early stages н your input is needed and welcome ╖ Precision luminosity measurement with cross angle seems p ossible ╖ Main lumi worry is p otential background from machine and physics backgrounds Main overall challenge is to engineer luminosity monitor and endcap without large areas with dead material ╖ Many costs in the forward region will b e fixed by R&D rather than part count н keep this in mind when designing detectors

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19 Sept 05 н David Strom н UO