The SNS Electron Detectors J' Gullotta

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The SNS Electron Detectors J. Gullotta D.
Gassner
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July 02 Review Comments
Committee Observation The present beam physics
understanding of electron cloud effects
anticipated in the SNS was described.
Implications may be significant for beam
stability and for beam diagnostics. Recommendation
Close communication between beam physics and
diagnostics people needs to continue through
design, commissioning, and operation so that
deleterious electron cloud effects, both on the
beam and on diagnostics capabilities, might be
unambiguously identified and quantified.
Committee Observation Electron collection
panels on IPMs and Argonne style electron
monitors were noted as possible means of
measuring electron presence in SNS, but
requirements seem to be ill defined. Recommendatio
n Beam physics and diagnostics groups should
determine clear requirements for electron
detection devices. Response to Recommendations
Collaboration with the physics group has been
used to determine requirements for the system.
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AP Requirements
Range 100pC/cm2/turn minimum collected
current 10nC/cm2/turn is expected to interfere
with beam We will design for the range,
5x10-11C/cm2/turn 10-6C/cm2/turn Data
Structure Digitize at 400MS/s, using standard
PCI scope card
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SNS Electron Detector

• Based on ANL- APS Design (Rosenberg)
• Status
• Several detectors installed in RHIC
• Waiting for electrons
• Prototyping a front-end amplifier

APS ED, no shield
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SNS Electron Detector System Architecture
Network
Event Link
Rack Mount Power Supply 0-100V Remote Controlled
Times 91421
PC
Detector Grid Collector
Volt Ref Out
DAC
Event link In Trig. Out
Trigger
Trig. In Sig. In
Amp Or Atten
Scope Card
50 ohm ½ Heliax
10V Battery
Digital Output
Gain Con.
Service Building
Ring
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RHIC Data
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Deliverables Process Variables

• Deliverables
• Detectors
• PC
• Amplifiers
• Attenuators
• Batteries
• Bias supplies
• PC Scope cards
• Trigger card
• DAC card

• Process Variables
• Turn-by-turn ED digitized signals (6), from
  scope
• Bias supply voltage reference
• Bias supply current readback
• Bias supply on/off bit
• Trigger

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Cabling Plan

• Cabling to Each Electron Detector
• 3/8 50 ohm Heliax signal cable
• Terminated in bulkhead N connectors with N to
  SMA adapters. Short, flexible, 50 ohm coaxial
  cables terminated in SMA connectors will be used
  to make the connections from the Heliax to the
  electronics and pickups.
• Times 91421 Coaxial bias cable
• Terminated with SHV connectors on both ends

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Schedule
To be determined