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VLPC system and VLPC system and Cosmic Ray test resultsCosmic Ray test results

M. EllisM. Ellis

Daresbury Tracker MeetingDaresbury Tracker Meeting

3030thth August 2005 August 2005

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Analog Front-End (AFE) Version 2Analog Front-End (AFE) Version 2

New design of the readout electronics for New design of the readout electronics for VLPCs.VLPCs.

Step along the path to AFEII-t, which will Step along the path to AFEII-t, which will add the ability to record TDC information add the ability to record TDC information for each hit.for each hit.

Prototype AFEII boards have been used Prototype AFEII boards have been used for the first time at D0 for work on the for the first time at D0 for work on the MICE tracker.MICE tracker.

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MICE tracker readout with VLPCsMICE tracker readout with VLPCs

Tracker

Waveguides

AFEII boards

VLPC cryostat

LVDS cables to VLSB module

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VLPC operating conditionsVLPC operating conditions Temperature needs to be kept at 9.00 Temperature needs to be kept at 9.00 ± 0.02 K.± 0.02 K. Cryostat/cryo-cooler combination controlled to Cryostat/cryo-cooler combination controlled to

hold cold-end at 6.8 K with heater on a feed-hold cold-end at 6.8 K with heater on a feed-back loop.back loop.

VLPC cassettes have 8 heaters, controlled VLPC cassettes have 8 heaters, controlled through the AFE board, that bring the through the AFE board, that bring the temperature up to 9.0 K and maintain it.temperature up to 9.0 K and maintain it.

Select appropriate bias voltage to optimise gain Select appropriate bias voltage to optimise gain vs noise rate. Optimisation depends on expected vs noise rate. Optimisation depends on expected data-taking rate.data-taking rate.

Bias voltage is applied through the AFE board.Bias voltage is applied through the AFE board.

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LVDS / VLSBLVDS / VLSB Low Voltage Differential Signaling (LVDS) is Low Voltage Differential Signaling (LVDS) is

used to transfer the ADC data from an AFE used to transfer the ADC data from an AFE board to a VME memory module.board to a VME memory module.

The cable is connected to the AFE board The cable is connected to the AFE board through the AFE back-plane.through the AFE back-plane.

VME LVDS Serdes Buffer (VLSB) boards are VME LVDS Serdes Buffer (VLSB) boards are VME devices containing memory and an LVDS VME devices containing memory and an LVDS interface.interface.

When the AFE board passes through a data-When the AFE board passes through a data-acquisition cycle, the ADC values are sent to the acquisition cycle, the ADC values are sent to the corresponding VLSB board and can then be corresponding VLSB board and can then be accessed over a VME/PCI interface (BIT3).accessed over a VME/PCI interface (BIT3).

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LVDS and VLSBLVDS and VLSB

Trigger/Timing

LVDS cables

VME/PCI

1553

VLSB modules

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InitialisationInitialisation

AFE boards need to be initialised before AFE boards need to be initialised before data-taking can begin. data-taking can begin.

This is achieved through the Mil-1553 This is achieved through the Mil-1553 interface. One 1553 can control all 4 interface. One 1553 can control all 4 boards on a MICE 2-cassette cryostat.boards on a MICE 2-cassette cryostat.

Initialisation includes:Initialisation includes: FPGA power on, programming and testingFPGA power on, programming and testing Trigger Pipeline (TRIP) chip programmingTrigger Pipeline (TRIP) chip programming VLPC bias voltage and temperature controlVLPC bias voltage and temperature control

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Timing and TriggeringTiming and Triggering FPGAs require a 53 MHz clock.FPGAs require a 53 MHz clock. AFE board has a number of operating modes:AFE board has a number of operating modes:

InitialiseInitialise AcquireAcquire DigitiseDigitise ReadoutReadout

The clock and mode control used to be provided The clock and mode control used to be provided by a SaSEQ board, now provided by an Avnet by a SaSEQ board, now provided by an Avnet board.board.

Avnet is able to control all 4 boards on a MICE Avnet is able to control all 4 boards on a MICE cryostat at once and requires no software cryostat at once and requires no software intervention to perform a intervention to perform a trigger/acquire/digitise/readout cycle.trigger/acquire/digitise/readout cycle.

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Avnet BoardAvnet Board

Connection to AFE Backplane

External trigger

RS232 cable

1111

Readout SequenceReadout Sequence External trigger is generated (e.g. cosmic ray trigger External trigger is generated (e.g. cosmic ray trigger

scintillators).scintillators). Trigger is ANDed with a pattern that matches the Trigger is ANDed with a pattern that matches the

tevatron bunch structure (needed for now, will be tevatron bunch structure (needed for now, will be replaced in later use for MICE).replaced in later use for MICE).

If trigger is accepted, signal is passed to Avnet board.If trigger is accepted, signal is passed to Avnet board. Avnet board causes the AFE boards to acquire, digitise Avnet board causes the AFE boards to acquire, digitise

and readout the data to the VLSB modules and then sets and readout the data to the VLSB modules and then sets the AFE boards ready for the next trigger.the AFE boards ready for the next trigger.

Data is retrieved from the VLSB modules over the Data is retrieved from the VLSB modules over the VME/PCI interface to a Linux PC.VME/PCI interface to a Linux PC.

Timing is critical as the trigger signal to the Avnet board Timing is critical as the trigger signal to the Avnet board needs to arrive 7 “bunch crossings” after the light from needs to arrive 7 “bunch crossings” after the light from the tracker arrives at the VLPCs.the tracker arrives at the VLPCs.

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Progress at FNALProgress at FNAL After a number of problems, have managed to After a number of problems, have managed to

operate the MICE cryostat with 4 AFEII boards.operate the MICE cryostat with 4 AFEII boards. Linux software written for MICE can now perform Linux software written for MICE can now perform

almost all of the initialisation sequence and was almost all of the initialisation sequence and was used for all data-taking.used for all data-taking.

Took data with an LED pulser attached to each Took data with an LED pulser attached to each VLPC cryostat in turn and then connected the VLPC cryostat in turn and then connected the tracker and collected a few thousand cosmic ray tracker and collected a few thousand cosmic ray triggers!triggers!

Tracker system has been sent to Japan and is Tracker system has been sent to Japan and is being setup there now...being setup there now...

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G4MICEG4MICE Several new features have been implemented in Several new features have been implemented in

preparation for the use of G4MICE in data-taking preparation for the use of G4MICE in data-taking and analysis of the KEK data:and analysis of the KEK data: User applicationsUser applications A few SciFi classes are now persistentA few SciFi classes are now persistent Interface to CERNLIB to make PAW histograms, etcInterface to CERNLIB to make PAW histograms, etc Code to decode raw data formatCode to decode raw data format Code to handle calibration dataCode to handle calibration data Code to handle “decoding” information (so far only for Code to handle “decoding” information (so far only for

original three stations)original three stations) First version of visualisationFirst version of visualisation Existing reconstruction already works with real data Existing reconstruction already works with real data

classes.classes.

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Pedestal WidthsPedestal WidthsMade with G4MICE

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Calibrations – Cassettes 105 & 111Calibrations – Cassettes 105 & 111

One channel from each cassette. Note 105 has a gain of ~20k and 111 has a gain of ~40k

Made with G4MICE

10 PE 10 PE

Cassette 105 Cassette 111

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High Gain Cassette – More LightHigh Gain Cassette – More Light

Made with G4MICE

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Calibration ResultsCalibration ResultsMade with G4MICE

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First look at Cosmic dataFirst look at Cosmic data

Still require work on “cabling” information (i.e. which Still require work on “cabling” information (i.e. which board/channel/MCM is connected to which board/channel/MCM is connected to which Station/Plane/Fibre)Station/Plane/Fibre)

Cabling information only for original three stations at the Cabling information only for original three stations at the moment.moment.

Calibration applied to raw hits and normal pattern Calibration applied to raw hits and normal pattern recognition applied up to the level of space points.recognition applied up to the level of space points.

Still need CMM data on station positions before attempt Still need CMM data on station positions before attempt at tracking can be made.at tracking can be made.

Need to construct a “dead channel” list to remove first 4 Need to construct a “dead channel” list to remove first 4 channels readout over LVDS. These channels are channels readout over LVDS. These channels are corrupted due to the very low data-taking rate. This is corrupted due to the very low data-taking rate. This is only an issue < 0.5 Hz!only an issue < 0.5 Hz!

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Light Yield (no tracking cuts)Light Yield (no tracking cuts)Made with G4MICE

2020

Doublet ClustersDoublet ClustersMade with G4MICE

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Hit DistributionHit DistributionMade with G4MICE

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Next StepsNext Steps

Add code to cope with new station/waveguide Add code to cope with new station/waveguide decoding.decoding.

Make best guess of waveguide connections to Make best guess of waveguide connections to new station (otherwise try all plausible options...)new station (otherwise try all plausible options...)

Obtain and use CMM information for station Obtain and use CMM information for station alignment.alignment.

Improve calibration information.Improve calibration information. Check higher-level reconstruction (points and Check higher-level reconstruction (points and

tracks).tracks). Finish executables and scripts for KEK test.Finish executables and scripts for KEK test.