Transcript MICE Tracker Update

MICE Tracker Update
M. Ellis
UKNFIC Meeting
25th August 2005
1
Story so far...
 2003/2004:
Three station prototype
assembled and operated at D0 using D0
equipment.
 February 2005: Sci Fi/VLPC technology
validated for MICE tracker
 March – August: Work on new hardware
(4th station, cryo-cooler & cryostat, AFEII
prototype, Avnet, etc) for MICE tracker,
leading towards:
 October 2005: Test beam at KEK
2
Previous test
 Used
a D0 test cryostat, able to hold two
VLPC cassettes (4 AFE boards).
 Only had access to two AFE (version 1)
boards, so readout 1024 channels.
 Software used was Excel/Visual Basic
code in regular use at D0 for testing of
AFE and calibration of VLPCs/AFE
boards.
 Need MICE specific hardware and
software!
3
Fourth Station
 New
specification (changed fibre pitch).
 Improved optical connector design.
 Station constructed at IC and new tracker
assembled in dark-room at IC.
 CMM machine used to determine station
alignment.
 Complete tracker made light-tight and
shipped to Fermilab..
4
5
Analog Front-End (AFE) Version 2
 New
design of the readout electronics for
VLPCs.
 Step along the path to AFEII-t, which will
add the ability to record TDC information
for each hit.
 Prototype AFEII boards have been used
for the first time at D0 for work on the
MICE tracker.
6
MICE tracker readout with VLPCs
Waveguides
Tracker
LVDS cables to
VLSB module
AFEII boards
VLPC cryostat
7
VLPC operating conditions
Temperature needs to be kept at 9.00 ± 0.02 K.
Cryostat/cryo-cooler combination controlled to
hold cold-end at 6.8 K with heater on a feedback loop.
 VLPC cassettes have 8 heaters, controlled
through the AFE board, that bring the
temperature up to 9.0 K and maintain it.
 Select appropriate bias voltage to optimise gain
vs noise rate. Optimisation depends on expected
data-taking rate.
 Bias voltage is applied through the AFE board.


8
LVDS / VLSB

Low Voltage Differential Signaling (LVDS) is
used to transfer the ADC data from an AFE
board to a VME memory module.
 The cable is connected to the AFE board
through the AFE back-plane.
 VME LVDS Serdes Buffer (VLSB) boards are
VME devices containing memory and an LVDS
interface.
 When the AFE board passes through a dataacquisition cycle, the ADC values are sent to the
corresponding VLSB board and can then be
accessed over a VME/PCI interface (BIT3).
9
LVDS cables
LVDS and VLSB
1553
Trigger/Timing
VME/PCI
VLSB modules
10
Initialisation
 AFE
boards need to be initialised before
data-taking can begin.
 This is achieved through the Mil-1553
interface. One 1553 can control all 4
boards on a MICE 2-cassette cryostat.
 Initialisation includes:



FPGA power on, programming and testing
Trigger Pipeline (TRIP) chip programming
VLPC bias voltage and temperature control
11
Timing and Triggering


FPGAs require a 53 MHz clock.
AFE board has a number of operating modes:




Initialise
Acquire
Digitise
Readout

The clock and mode control used to be provided
by a “SaSEQ” board, now provided by an
“Avnet” board.
 Avnet is able to control all 4 boards on a MICE
cryostat at once and requires no software
intervention to perform a
trigger/acquire/digitise/readout cycle.
12
Avnet Board
RS232 cable
Connection to AFE Backplane
External trigger
13
Readout Sequence






External trigger is generated (e.g. cosmic ray trigger
scintillators).
Trigger is ANDed with a pattern that matches the
tevatron bunch structure (needed for now, will be
replaced in later use for MICE).
If trigger is accepted, signal is passed to Avnet board.
Avnet board causes the AFE boards to acquire, digitise
and readout the data to the VLSB modules and then sets
the AFE boards ready for the next trigger.
Data is retrieved from the VLSB modules over the
VME/PCI interface to a Linux PC.
Timing is critical as the trigger signal to the Avnet board
needs to arrive 7 “bunch crossings” after the light from
the tracker arrives at the VLPCs.
14
Progress at FNAL

After a lot of problems, have managed to
operate the MICE cryostat with 4 AFEII boards.
 Linux software written for MICE can now perform
almost all of the initialisation sequence and was
used for all data-taking.
 Took data with an LED pulser attached to each
VLPC cryostat in turn and then connected the
tracker and collected a few thousand cosmic ray
triggers!
 Tracker system is currently on its way to Japan...
15
G4MICE
 Several
new features have been
implemented in preparation for the use of
G4MICE in data-taking and analysis of the
KEK data:




User applications
A few SciFi classes are now persistent
Interface to CERNLIB to make PAW
histograms, etc
Code to decode raw data format
16
Pedestal Widths
17
Calibrations – Cassettes 105 & 111
10 PE
10 PE
One channel from each cassette.
Note 105 has a gain of ~20k and 111 has a gain of ~40k
18
High Gain Cassette – More Light
19
Calibration Results
20
First look at Cosmic data
 Still
require work on “cabling” information
(i.e. which board/channel/MCM is
connected to which Station/Plane/Fibre)
 First look involves selecting channels with
a good calibration and plotting ADC
distribution in units of Photo Electrons.
 More refined analysis requires use of
G4MICE (coming very soon...)
 Light is seen coming from the tracker:
21
Cosmic Ray data





Pedestals subtracted
No Common Mode
Noise subtraction
Gains used to express
ADC as PE
No tracking or other
cuts
All channels with a
signal above 2.0 PE
are shown
22
Next Steps
 Work
ongoing in G4MICE to allow all
future calibration/alignment and analysis to
be performed using G4MICE.
 Need to sort out channel map and attempt
tracking using G4MICE.
 Prepare Linux software to control Avnet
board and finalise newer TRIP
programming scheme (much faster).
 Take data at KEK...
23