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Detector Interface Issues

July 30th, 2004 Victoria Linear Collider Workshop Victoria, BC

Eric Torrence University of Oregon

Eric Torrence

1/8

July 2004


Overview

Physics-related Beam Instrumentation · Beam Polarimeters · Beam Energy Spectrometers

Forward Detectors · · · · Traditional Luminosity Monitor Pair Monitor veto counter Forward Tracker?

Detector - Machine Data Flow · Detector -> Machine diagnostic info (slow) · Detector -> Machine feedback inputs (fast) · Machine -> Detector information

Eric Torrence

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July 2004


Polarimeter
532 nm Frequency Doubled YAG Laser e­ Mirror Box Pockels Cell Left or Right Circularly Polarized Photons Focusing and Steering Lens Mirror Box (preserves circular polarization) Compton Back Scattered e­ Analyzing Bend Magnet
1-93 7268A1

e+

SLD e­ Laser Beam Analyzer and Dump "Compton IP"

Cerenkov Detector Proportional Tube Detector

· · · ·

Gas Cherenkov electron detector ~ 10 channels, dual gain Photon calorimeter ~ not read out in collisions Laser diagnostics ~ few dozen channels Machine diagnostics ~ few dozen channels*

Estimate: 2 x 200 channels at 192x120 = 23 kHz (save all raw data?) Also slow monitoring ~ few dozen channels @ 1 Hz
Eric Torrence 3/8 July 2004


Energy Spectrometer
180µrad

Chicane + RF BPMs ~ 1 km upstream of IP (x2) · Dozen BPM channels at crossing rate · Dozen fast position monitoring channels (ie: interferometer) · Many many slow monitoring channels (LEP spectrometer had ~100 temperatures alone @ 1 Hz) · Fast machine input (orbit information, currents, RF status, ...)
Vertical Disp. (mm) 600 400 200 0 -200 -400 -600
20% Enom 1 mRad Stayclear 3 mRad Dipoles SR Fan Detector Plane To Dump 250 GeV Beam Horiz. Wigglers Compton Endpoint 750 MeV/mm

0

20

40

60

80

100

120 140 Longitudinal (m)

Chicane + position-sensitive SR detector downstream (x2) · 2 x 20 cm / 100 µm = 4k at crossing rate · Modest slow monitoring needs · May not need to save all raw data Need machine inputs, filtered data useful in real time for feedbacks?
Eric Torrence 4/8 July 2004


Forward Detectors
0.5

0.4

113mrad Inst. Mask W 46mrad BeamPipe Pair-LuMon LowZ Mask W Support Tube HCAL
2 2.5 3

0.3

0.2

W

0.1

0

QD0 Exit radius 2cm @ 3.5m

-0.1

W

-0.2

-0.3

-0.4

-0.5 0 0.5 1 1.5

E C A L

YOKE
3.5 4

Different Functionality · Classic luminosity monitor (outside pair background, 20-100 mRad) · Pair monitor (front surface of pair region, 5 - 20 mRad) · veto monitor (find ~100 GeV electrons in 50 TeV pair backgrounds) Could potentially all be the same detector technology
Eric Torrence 5/8 July 2004


Forward Detectors II LUMCAL · · · · Sampling calorimeter, guesstimate 0.3 m2 Identical readout to main Ecal? 20ish layers, 16 mm2 pixels -> 400 k pixels (x2) Probably survive with 120 Hz readout + time tag

PAIRMON · Unique device (3D silicon has been proposed) · Sample pair distribution for machine diagnostics Collision parameters, real-time lumi measurement, ... · Read out as fast as possible (crossing rate ideal) · 100µm pitch, 6cm radius -> 1M pixels (x2) · Processing to provide info for IP feedbacks? PAIRCAL Many technologies proposed, numbers from Zeuthen forward-cal collaboration · 30 layer diamond-tungsten sampling calorimeter · 15k channels in total (x2) · Single crossing & single channel readout mandatory to find single electrons in pair background · Hardware-based algorithm dangerous...
Eric Torrence 6/8 July 2004


Machine <-> Detector Data Flow Machine -> Detector Need exquisite understanding of beam parameters to control systematics in Lumi, Pol, and Energy Need machine information "available" to analyses · · · · IP collision parameters Deflection scan results Currents, bunch lengths, RF status, orbit information Collimator settings, Enom, source settings, ...

Some devices (ie: polarimeter) may need this in near real time to do online data reduction Detector -> Machine Need as much diagnostic information as possible to maintain integrated luminosity Some detector information useful for IP feedbacks? · · · · PAIRMON integrated and differential rates Downstream spectromer tails Background monitoring Dithering/feedback for pol and energy?

Eric Torrence

7/8

July 2004


Putting it all together

Beam Instrumentation historically runs in a semi-autonomous manner from either machine or detector. I consider this a virtue.

Good reasons to coordinate with machine BI thinking. Common framework/technology for collecting data from distributed detectors might make everyone's life easier.

Need to think harder about what is useful machine information, but my prejudice is to save EVERYTHING.

Similarly, essentially any detector channel should be available to log to the machine DB just as any other machine element.

Eric Torrence

8/8

July 2004