Limited%20Streamer%20Tubes%20for%20the

1

Limited Streamer Tubes for the IFR Barrel
INFN Ferrara, Frascati, Genova, Padova,
Roma US Ohio State, Oregon Princeton, SLAC, UCSD

Stewart Smith
Experimental Program Advisory Committee SLAC,
June 12 2003
2
Motivation

• Oct 2000 IFR flagged as major problem by
  Technical Review (Gilch)
• Major RD toward remediation close but no cigar
• Decision to upgrade endcap with RPCs, launch RD
  for barrel upgrade.
• Dec 2002 IFR Barrel Replacement Review
  Committee (Ratcliff, Hearty chairs) analyzed role
  of muon and KL ID in the current BABAR physics
  program and in the program we foresee for the
  future.
• Committees report examines
• Solid angle coverage of IFR systems
• Overview of relevant physics processes
• Closer look at selected processes
• Characteristics of the current IFR barrel
• Simulation of new absorber configurations
• Recommendation of LST as new detector

3
Upgrade of IFR

• Forward Endcap
• 5 brass layers
• New RPCs to improve efficiency
• Installed summer 2002

4
Physics Program for the IFR

• Muons are critical for many analyses over the
  long-term BaBar physics program
• Semileptonic decays
• Leptonic decays
• Electroweak penguins
• Processes involving J/y or y(2S), including rare
  decays
• Lepton tagging (CP, CPT studies, mixing, certain
  rare decays)
• Reconstruction of B?Dln on one side of the event
  
• R at low energies via Initial State Radiation
• Unthinkable for a comprehensive B-Factory
  detector not to have good muon identification.
• Taken for granted in such experiments!
• We need all the statistics we can get (rare
  decays, backgnd reduction, restricted areas of
  phase space, etc.).
• m / e comparisons to reduce systematic errors
  in precision measurements.

5
Measurements using the IFR (I)

• Rating system IFR gives (some benefit),
  ( significant benefit),
• 
  ( large benefit), (essential
  information)
• Modes highlighted in red will be discussed in
  more detail.

6
Measurements using the IFR (II)
R via initial state radiation g-2,
etc

• Most of these measurements are underway.
• Many will continue long into the future.
• (The comment stat indicates that the
  measurement is statistics limited)

7
Flavor-Changing Neutral Current Decays
B?Kll -, B? Kl l -, and B? Xsl l -

• Three diagrams in the Standard Model penguins
  (g, Z), and the WW- box

Possible new physics contributions
8
B? Kll-, B? Kll-, B? Xsll-
ICHEP 2002 82 fb-1

• B? K l l - is rarest observed B decay ( 8 x
  10-7)
• Two leptons?very sensitive to e and m
  performance.
• Current sensitivity dominated by ee- channels in
  BABAR due to low m effic. (but not in Belle).
• Current significance 4.4 s (K) 2.8s (K)

9
Muon Efficiency vs Time

• K()ee modes e stable
• K()mm modes e lower and falling with time.
• Will lose 2/3 of the mm- events without IFR
  barrel.

10
Vub from Rare Semileptonic Decay

• Challenges
• Small branching fractions for b?uln
• Large b?cln backgrounds.
• Theoretical uncertainties from strong interaction
  effects.
• Experimental approaches with high potential to
  reduce theoretical errors
• Exclusive B?p l n at high q2, using neutrino
  reconstruction à la CLEO theory from lattice
  QCD.
• Inclusive B?Xu l n, using fully reconstructed B
  sample as tags theory from heavy quark
  expansion.
• Both methods need large event samples.
• m/e comparison important as precision increases.

11
Inclusive B?Xuln with Fully Reconstructed tags
G(B?Xuln) / G( B ? Xcln)

• Can use more of lepton momentum range than in
  inclusive endpoint method.
• This reduces model dependence.

B?Xuln
12
The IFR as Muon Detector

• 19 active layers, very finely segmented.
• There are only 5.1 lint .
• RPCs in Layer 19 are dying, are inaccessible,
  and cannot be replaced. We will lose 10 cm of Fe,
  leaving only 4.5 lint
• This is marginal for a muon system.

pgt1 GeV/c

• Spectrum of ranges in barrel for muons from B?Xu
  l n (in lint)

13
Proposed Absorber Improvement

• Want to add as much absorber as possible, but we
  are highly constrained by earthquake
  considerations.
• Proposed configuration places more emphasis on
  muon ID, while still preserving most of the KL
  efficiency.
• replace 6 active layers (5, 7, 9, 11, 13, 15)
  with 2.2 cm brass plates, compensating for the
  loss of layer 19 and bringing the total absorber
  thickness to about 5.3 lint .
• This will be adequate for essentially all
  measurements.

14
IFR Barrel Performance Pion fake rate vs e(m)
Simple muon selector -- uses only lint info.
(neural net algorithms improve rejection by
factor 2)
Design June 2002 LSTs Only LSTs Brass
pm gt 2 Gev/C
Muon Efficiency (Monte Carlo)
15
The LST Team

• M. Andreotti, D. Bettoni, R. Calabrese, V.
  Carassiti,
• G. Cibinetto, A. Cotta Ramusino, E. Luppi, M.
  Negrini, L. Piemontese
• Ferrara University and INFN
• R. Baldini, A. Calcaterra, U. Denni, P. Patteri,
  A Zallo
• Laboratori Nazionali di Frascati dellINFN
• R. Capra, M. Lo Vetere, S. Minatoli, S.
  Passaggio, C. Patrignani, E. Robutti
• Genova University and INFN
• T. Allmendinger, K.K. Gan, K.Honscheid, H. Kagan,
  R. Kass, J.Morris,
• C. Rush, S.Smith, Q. Wong, M.Zoeller
• Ohio State University
• R. Frey, N. Sinev, D. Strom, J. Strube
• University of Oregon
• C. Fanin, M. Morandin, M. Posocco, M. Rotondo, R.
  Stroili, C. Voci
• Padova University and INFN
• J. Biesiada, G. Cavoto, N. Danielson, R.
  Fernholz, Y. Lau, C. Lu, J. Olsen, W. Sands,
  A.J.S. Smith
• Princeton University
• S. Morganti , G Piredda, C. Voena
• Roma La SapienzaUniversity and INFN
• D.B. MacFarlane, H.P. Paar

16
LST design

• Option 1 single-layer large cell (15x17 mm)
• Option 2 double-layer small cell (9x8mm)
• Readout of x and y coordinates
• in both options from outside
  strips

Graphite- Coated PVC
17
Large cell is the Baseline

• Mechanically more robust, Looser tolerances
• Lower failure rate
• 0.1/year failure rate in Macro over more than a
  decade.
• Comparable net efficiency loss to that of
  double/layer
• 1.5 mm thinner
• Only 1/3 as many cells
• Simpler HV, Gas systems
• Significantly cheaper
• But, RD slower off the mark than for small
  cells.
• Required new dies, molds, to make full
  prototypes.
• Awaiting confirmation of performance to make
  final decision
• Simulations, which agree with measurements on
  9x9s (E fields, resolutions, tolerances) are
  very encouraging.
• Just today, prototypes at Frascati and
  Pol.Hi.Tech have been put under voltage so far
  so good, but.
• Should know within a week!

Breaking News!
18
Progress Since Decision

• 22 standard (9x9) tubes produced by vendor
  (Pol.Hi.Tech)
• Early verification of vendors capability.
• Good plateaux at factory with binary (flammable)
  gas mixture (larger than 500V)
• Shipped to Ferrara, Princeton and Columbus, tests
  with ternary (safe) gas mixture underway.
• Preproduction prototypes underway (Ferrara,
  Frascati, Padova)
• 10 single layer (17x15) prototypes ordered first
  tubes ready by Jun. 5
• 20 double layer (9x8) tubes ordered first tube
  ready by Jun. 12 (delay due to dies production)
• Final strip prototypes ? and Z arrived in
  Ferrara.
• Test of the readout chain underway (Ferrara)
• Final strip setup
• Final preamp-discriminator prototypes of Front
  End Card ready
• Electronics (Ferrara, Genova, Ohio State)
• Detailed electrical schematics for Front End Card
  underway
• Review at July workshop.

19
Progress (contd)

• Integration/Installation work underway at SLAC
• SLAC and Princeton engineers meet weekly.
• Detailed work for the 2 sextants to be installed
  in 2004 (1 and 4)
• Workshops
• Jan 11-12 in Princeton
• Conceptual design, organization, division of
  responsibilities
• Mar 17/18 in Rome (and Pol.Hi.Tech).
• Mainly QC and final design for prototypes
  pre-production
• Apr 24/26 in Columbus (US groups).
• Mainly assembly and installation issues
• May 26/27 in Ferrara.
• Mainly QC, production issues, module assembly,
  preparation of documentation for EPAC
• Engineering Design Week Jul. 14 18 at SLAC.
• Final design, installation issues, and
  electronics review
• Integrate SLAC and Outhouse engineering effort

20
RD activities

• Measurements of plateaux, pulse-heights, etc
• Aging tests
• Strip signal studies
• conductive rib effect on the phi strips
• Q distribution on z strips
• Signal propagation, reflections at
  strip/cable connection
• E-field, drift-time characterization of large
  cell
• Gas flow studies
• FEA simulation
• Full length test results.
• Anode wire study
• Surface quality
• Effect of wire diameter on plateau width.

21
9x9 Plateaux at PHT, binary gas
Larger than 500 V
(31 Ar 69 Isobutane)
22
Preliminary 9x9 plateaux, ternary (SLD) gas
mixture (Ferrara)
Gas mixture CO2/C4H10/Ar(88/9.5/2.5) Vthreshold
35mV ?dead 400ns
400 V wide plateau
23
Efficiency with cosmic ray trigger (OSU)
400 volt plateau
Efficiency limited to lt 100 By geometry
Ternary ZEUS Gas, 8 Isobutane
24
Charge spectrum (in ternary gas) (Princeton)
(ZEUS Gas -- 8 Isobutane)
30 mv
30 mv
Trigger Threshold
5 mv
4700 V
5000 V
High Voltage
25
Threshold effect on counting rate(Princeton)
Charge spectrum suggests lack of clear transition
between avalanche mode and streamer mode.
Therefore the threshold will play a big role for
the plateau. With 5mV instead of 30mV threshold,
the plateau is much better even for ternary gas.

Zeus gas mix
Binary gas mix
(8 Isobutane)
(69 Isobutane)
26
First Test of Large Cell (Frascati)
Just Received!

• Machined prototype, 70cm long
• Cosmic Ray Singles Rate counted for 5 minutes
• SLD Gas (9.5 C4H10)

Counts

• Maiden Voyage
• ? After 1 hour

High Voltage
27
Aging Tests (Princeton)

• Accumulated charge 0.75C/cm (worst dose
  expected by 2010 0.1C/cm)
• No big drop of the signal charge and
  self-sustaining discharge occurred.
• The chamber is still running smoothly.

28
Quality Control

• Absolutely crucial to get this right!
• Q/C procedures at Pol.Hi.Tech. (PHT)
• Have been discussed, defined in various meetings
  with the company and have been accepted.
• Test equipment to be supplied partly by INFN, and
  accepted by the company.
• Tube acceptance criteria to be defined together
  with PHT.
• Procedures and equipment in place by end of
  August
• Q/C and long term test procedures at US sites
  basically designed.

29
Module Assembly Plan

• Ohio State and Princeton preparing facilities
  for module assembly.
• Both universities fabricating parts for assembly
  fixtures.
• Shipping and testing boxes are being designed.
• Planning for testing and quality control is in
  progress.
• Installation procedures coordinated by SLAC and
  Princeton engineers.

30
Composition of Module Arrays (large cell)
(Widths in mm)
Circles indicate number of modules per sextant
F strips
31
Installation and Replacement of Modules
Installation corner and center plates
removed. Replacement center plate(s) removed,
corner plates remain

32
HV Power Supply (OSU, Padova)

• OSU HV System design in final phase
• Further refined prototype. Ripple now lt 25 mV,
  and will be significantly less with tube and HV
  capacitor connected. (CAEN specs list ripple as lt
  50 mV.)
• First tests of control logic, current and voltage
  read-out
• Full prototype
• 96 channels, 2u, 19 (twice the CAEN density)
• Current monitor for each channel, 48 ch. share
  common HV setting (12 in CAEN system)
• Diode protection circuit integrated.
• CAEN HV Supplies from LVD experiment may be
  available
• OSU engineers believe the (ZEUS) diode
  protection circuit can be fit into the modules.
  Need to find solution for external HV
  distribution (SHV?)
• Should be able to evaluate suitability and
  availability soon.

33
(No Transcript)
34
Ferrara
35
(No Transcript)
36
SIMULATION

• Goals
• Implement a full GEANT4 based simulation
• No workaround
• Just try to understand the whole machinery and
  adapt to our need
• Reuse as much code as we can
• Work in the most recent functional release
  (12.5.2)
• Need to learn some new CDB technology
• Understand the Detector Model
• mostly done
• Status
• Working LST simulation Ready by the end of June
• We continue to need help from the IFR experts
• Already have had a lot of useful interactions...

37
From Prototypes to Project

• June 12 -- EPAC Review
• June 15 -- Cost/Schedule/WBS prepared
• June 22 -- INFN Gruppo Uno Evaluation
• June 27 -- BaBar IFC Meeting
• June 30 -- Large/Small Cell Decision
• Aug 1 -- Place Orders for Tubes
• Oct 1 -- Tube Production begins
• Feb 1 04 -- 1/3 tubes shipped to
  Princeton/OSU
• May 1 -- Modules for 2 sextants to SLAC
• July 1 -- Installation of 2 sextants
• July 2005 -- Remaining 4 sextants (ready
  earlier)

38
Summary

• Physics with ms is essential to BABARs
  long-term program.
• Barrel IFR provides about 50 of our muon
  acceptance.
• In addition to the added statistical power, muons
  are also valuable because they have very
  different systematics from electrons (Different
  detectors, much less radiation than from
  electrons, etc.)
• Important modes with 2 leptons, such as B?Kll,
  B?Kll, and B?Xsll, would be severely affected
  without the barrel replacement.
• Muon ID suffers from inadequate material in
  current IFR.
• Already marginal, exacerbated by impending demise
  of layer 19.
• Muon ID can be significantly improved by
  replacing some of the active detector layers with
  brass.
• LST project is well underway, strong INFN/US team
  in place.
• With strong competition from Belle and soon from
  CDF, BABAR needs the IFR barrel replacement.

39
Backup Slides
40
Solid Angle Coverage
Region Lab frame polar angle (radians) Fractional qCM coverage (with f acceptance) Coverage relative to total
Pure barrel 1lt qlab lt 2 0.413 (0.380) 0.52
Barrel/fwd endcap overlap 0.7lt qlab lt 1 0.185 (0.170) 0.23
Pure fwd endcap 0.3lt qlab lt0.7 0.194 (0.178) 0.25
Sum 0.3lt qlab lt2 0.792 (0.729) 1.0

• Pure Barrel represents 1/2 of our muon
  acceptance.
• Backward Endcap is ignored wont be replaced.
  

41
Composition of Module Arrays (small cell)
(Widths in mm)
Circles indicate number of modules per sextant
F strips
42
General Infrastructure for Q/C

• QC data and other relevant information collected
  by hand or, whenever possible, automatically with
  several DAQ stations.
• Common systems at PHT, Princeton, OSU, and SLAC.
• Labview will be used to write the DAQ software
  and design the interface.
• The DAQ stations will be operated by physicists
  on shift and/or PHT personnel.
• All DAQ stations will be on a wireless LAN.
• The DAQ station output will be simple text files.
• Local production database will be available on
  site.
• Data files will be transferred every day to an
  outside server to be imported in the official
  offsite LST database.

43
Scope of Q/C Activities at PHT

• Barcode labelling
• Inspection of profiles
• Mechanical
• Graphite coating
• Resistivity Measurement
• Inspection of jackets, endcaps, circuit cards
• Gas tightness (leak test)
• Wire check
• Wire-cathode distance measurement
• HV conditioning and plateau measurement
• Long range tests

44
OSU HV Prototype (5 ch)
15 V In
Floating 5V Supply
HV Op-Amp
Current Monitor Outputs
Current Monitor Protection
0-5 kV Out
6kV Dc/Dc
45
Prototype HV Connector (OSU)

• Integrated HV connectioncapacitor
• Machined plastic prototype.
• Need to design connection between tube ground
  and strip ground planes.
• Production to be done in industry

HV connector
Endcap end
46

• Digitally, LSTs present themselves to DAQ like
  RPCs
• Meetings held with Data Flow folks

47
(No Transcript)
48
(No Transcript)
49
Preamp Tests at OSU

• Built pre-amps and receivers following Angelos
  design
• They work as expected. Some details (termination)
  being discussed between the engineers (Chuck,
  Angelo)
• Detailed studies using
• Pulse generator
• 9x9 prototype tube (17)
• 40 ft twisted-flat cable (Amphenol)
• Tested several configurations
• Tube -gt Receiver -gt Oscilloscope
• Tube -gt Pre-amp -gt Receiver -gt Oscilloscope
• Tube -gt 40 ft cable -gt Receiver -gt Oscilloscope
• Tube -gt Pre-amp -gt 40 ft cable -gt Receiver -gt
  Oscilloscope
• Preliminary conclusion if noise levels at BaBar
  are comparable the preamp on the tube might not
  be necessary.

Scope pictures
50
Pre-amplifier tests
40 feet of twisted pair AMP 425-3016-034
receiver amp
preamp
Vin
Vch
Vout
Gnd
A
9x9 mmTube
Vin-
1nF
HV
scope triggered on tube signal
Vin
Vin
Vch
Vin-
Vout
Vout
51
Cable tests, N0 Pre- amplifier (OSU)
40 feet of twisted pair AMP 425-3016-034
receiver amp
Vin
Vch
Vout
Gnd
A
9x9 mm Tube
Vin-
1nF
HV
scope triggered on tube signal
Vin
Vin
Vin-
Vch
Vout
Vout
Pulses make it down 40 of cable in good shape!
52
Ferrara
53
BaBar IFR upgrade LST readout status report
610

• 3. PROGRESS ON READOUT ELECTRONICS
• 3.a Recalling the outline of the LST-FE readout
  crate in the baseline version

54
(No Transcript)
55
LST Workshop Ferrara, Monday-Tuesday May 26-27,
2003   Proposed structure we designate a
chair for each session and a discussion leader
for each topic. The discussion leader will begin
with a brief (5-10 minute) summary of status and
issues and lead the ensuing discussion the chair
will keep things moving along and will write down
the action items.  
Ferrara Workshop, Monday May
26   Session I. Tube/Module design.
Chair Mauro 0845 Identify commonalities,
differences, plusses, minuses between large and
small cell designs.

discussion led by chair 0900 Mechanical
tolerances, robustness of tubes (large cell
/small cell) --Vito 0915 Present state of endcap
design --Federico 0930
Gas flow issues within tube and modules
--Jim O 0945 HV connection design, issues
--Angelo 1000 Phi Strip
design, connections
--Angelo 1015 Discussion 1045 Break   Session
II Module construction Chair
Richard K. 1100 Module construction, mechanical
-- Bill S 1115 Module
construction, electrical
-- Angelo 1130 Optimization of accessibility vs
complexity 1200 Discussion, agreement on action
items 1230 Break   Session III Z-strips and
electronics Chair Livio 1330 Z-strip
design
-- Angelo 1345 Z-strip mechanical issues,
involving UCSD, installation 1400 Front-end
Electronics issues
-- Angelo --thresholds, in light of
prototype results. --FECs on detector
or in crates? 1430 Readout Crates
-- Maurizio
1450 HV System
-- Richard K. Can
we decide on LVD vs OSU design? 1510 Slow
controls (HV, temp, gas, etc) 1530 Break  
Session IV. Q/C at Pol.hi.tech, elsewhere Chair
Silvio 1600 Overview, list of procedures
/tests (also listed on Elba agenda) --
Diego 1615 Apparatus, schedules

-- Gigi 1630 The superbox can it be
everything to everyone? --
Bill S 1650 Relationship with Pol.hi.tech
1705
U.S. Participation at Pol.hi.tech
-- Jim O. 1715
Q/C at module construction sites
-- Jim O, Richard K 1730 Q/C
at SLAC
-- Charlie, Bob 1745
Break     Session V Preparation of EPAC
Proposal Chair Stew 1815 Status,
weak parts, action items --
Livio 1830 WBS, Schedule, Assigning names to
tasks -- Richard F by phone 1850 Break into
discussion groups 1930 Adjourn to fabulous
restaurant    
56
Ferrara, Tuesday May
27       Session VI Gas system, Safety
Chair Charlie 0830 Review of requirements,
SLD, RPC gas systems, -- Bob Defining
elements of system
-- Bob 0900 Gas System Schedule 0915 Safety
overview, list of items
-- Mauro 0930 SLAC safety approval procedures
-- Charlie, Bill W? 0945
Duties of LST Safety Officer 1030 Break
   Session VI. Parallel sessions 1100
A. Writing groups work on proposal
B. Detailed issues of module/ tube
design, integration, removal
C. Develop safety organization 1215
Lunch   Session VIII Prototype schedules,
issues, results Chair Roberto
(remember weve already discussed this in
Elba) 1445 Any new results, or conclusions since
Elba 1500 Round-table discussion of prototype
results from Pol.Hi.Tech, Ferrara,
Princeton, OSU -- Are they consistent? -- Do we
see adequate performance? -- What further tests?
-- Can we widen plateaux? --Different gases?
More sensitive electronics? 1545 Pol.Hi.Tech
construction status, schedules
Roberto 1600 Small parts status,
schedules , issues
Mario 1615 Electronics for prototype module
test 1630 Break    
Session IX. Conclusions 1700 Planning for SLAC
LST workshop, week of July 14-18 1745 Brief
Reports from Parallel Sessions, Proposal
1830 Review of Action Items by Session
Chairs 1900 Adjourn
57
E-field on the wire surface
Small cell, 4700V
Big cell, 5500V
E(_at_center) 198853V/cm E(off center)
202603 ?E/E 1.89
E(_at_center) 205135V/cm E(off center)
206931 ?E/E 0.876
58
Anode wire diameter tolerance
We can control the anode wire diameter within 1
of 100?m. Estimate the effect of this variation
to the effective anode wire voltage
Rc is the equivalent cathode radius, for big cell
it is 1cm, for small cell it is 0.6cm. x is the
anode wire radius.
E-field on the anode wire surface
For big cell _at_ 5500V ?V -44.6V For small cell
_at_ 4700V ?V -37.2V
The difference between big cell and small cell is
very small.
59
Dead time effect on counting rate
The limited streamer signal can have after-pulse,
which is generated by the photoelectrons due to
UV photons hitting on the LST wall.
Drift time from walls
From the drift time plot we can see if the dead
time longer than 300ns, all first round of
UV-photoelectrons would buried in the primary
pulse.