1. 5th Super B Workshop
Detector R&D Program – Plenary Session, May 9, 2007 – David W.G.S. Leith

2. We consider the detector presented in the CDR
SUPERB Detector R & D.
We consider the detector presented
in the CDR   
May 9, 2007
SuperB Detector R&D
David Leith

3. Detector Layout BASELINE OPTION May 9, 2007 SuperB Detector R&D
Below the mid-line we have our proposed detector. The upgrades are :-
New beam pipe at small radius and reduced material thickness; a new inner layer vertex detector; a new drift chamber;
End cap PID using TOF (if it passes physics review) and two versions of the DIRC system – one a simple replacement
of the PMT’s, and the other a new focusing system with smaller mass and physical size, but requiring serious R&D and substantial costs; new forward electromagnetic calorimetry using LSO crystals; and a scintillator based muon system.
OPTION
May 9, 2007
SuperB Detector R&D
David Leith

4. “What subsystems need R&D work” ? “Who is doing the work” ? and
May 9, 2007
SuperB Detector R&D
David Leith

5. Our friends from Pisa have been doing
The Beam Pipe
Our friends from Pisa have been doing
nice work on a clever, low mass beam
pipe that can also remove the heat from
the layer 0 vertex detector chips.
May 9, 2007
SuperB Detector R&D
David Leith

6. Beam pipe 1.0 cm inner radius Be inner wall
≈ 4um inside Au coating
8 water cooled channels (0.3mm thick)
Power ≈ 1kW
Peek outer wall
Outer radius ≈ 1.2cm
Thermal simulation shows max T ≈ 55°C
Issues
Connection to rest of b.p.
Be corrosion
Outer wall may be required to be thermally conductive to cool pixels
You saw this at our last workshop in Tor Vergata,
and you will hear more this afternoon in the parallel sessions.
May 9, 2007
SuperB Detector R&D
David Leith

7. Vertex Detector silicon work .
You will hear details of this work in the parallel sessions.
The Italian groups are very well supported for the pixel R&D,
and have a strong team working
on a hard and important problem.
May 9, 2007
SuperB Detector R&D
David Leith

8. Layer0 striplets R&D issues
Technology for Layer0 baseline striplet design well estabilshed
Double sided Si strip detector 200 mm thick
R&D confirms a clear S/N ~ 25.
Readout speed and efficiency are not an issue
with the expected background rate
(safety factor x5 included)
Possible gain in the total material budget for
L0 with striplets (from 0.45%  0.35% X0)
with some R&D on the connection between
the silicon sensor and the readout electronics:
May 9, 2007
SuperB Detector R&D
David Leith

9. Layer0 MAPS R&D issues Extensive R&D needed
CMOS Monolithic Active Pixels are a very promising “new device”, but so far have never been used in a real operating detector.
Extensive R&D needed
Fast readout architecture
Sensor optimization
Radiation hardness
Mechanical issues: Sensor thinning, power, light cooling development.
CMOS MAPS is an option for the ILC vertex detector  many aspects of the R&D are common.
May 9, 2007
SuperB Detector R&D
David Leith

10. Present Status on MAPS R&D (I)
Very simple in-pixel readout developed by several groups with good efficiency & resolution performance
Readout speed for large detector area is limited by the sequential readout. Trying to implement data sparsification at the detector periphery (column level) to improve speed.
May 9, 2007
SuperB Detector R&D
David Leith

11. Present Status on MAPS R&D (II)
3x3 matrix, full analog
4x4 matrix with sparsified readout
Starting from the triple well MAPS design 6 test chips produced 
8x8 matrix
Sequential readout
Readout Architecture data driven with sparsification and timestamp information is under development:
Simulation under way to evaluate performance with the expected SuperB background rates.
First small chip in production, medium size prototype in production by the end of 2007.
Residual capacitive coupling between the digital lines and the sensor (C~10 aF !!!) is an issue: crosstalk observed.
Shielding with metal planes inserted to cure the problem in the next chips in productions.
May 9, 2007
SuperB Detector R&D
David Leith

12. SLIM5 Collaboration
The SLIM5 Collaboration has a quite detailed project plan to build a prototype of a thin silicon tracker (MAPS and thin silicon striplets modules) with LV1 trigger capabilities (based on Associative Memories).
Important aspect of the project is to develop light mechanical and cooling structures for thin silicon modules to benefit of the very low material budget of the sensor itself.
Test of the prototype tracker in a test beam in 2008
Several Italian Institutes involved in the project:
Pisa (coordination), Pavia, Bergamo,Trieste, Torino, Trento, Bologna
R&D project supported by the INFN and the Italian Ministry for Education, University and Research.
May 9, 2007
SuperB Detector R&D
David Leith

13. Drift Chamber
You will hear a talk this afternoon on using a similar chamber design as that being proposed for the ILC.
May 9, 2007
SuperB Detector R&D
David Leith

14. DCH Basic technology adequate. Cannot reuse BaBar DCH because of aging
M. Kelsey
Basic technology adequate.
Cannot reuse BaBar DCH because of aging
Baseline:
Same gas, same cell shape
Carbon fiber endplates instead of Al to reduce thickness
 Need to do complete background estimate
Options/Issues to be studied:
Miniaturization and relocation of readout electronics
Critical for backward calorimetric coverage
Conical endplate
Further optimization of cell size/gas
May 9, 2007
SuperB Detector R&D
David Leith

15. Particle Identification System
May 9, 2007
SuperB Detector R&D
David Leith

16. SLAC Group B is working on : # 3-D focusing DIRC implementation;
# very fast time measurement;
# qualifying MCP PMT’s from various
vendors;
# behaviour of MCP PMT’s in high
magnetic fields.
May 9, 2007
SuperB Detector R&D
David Leith

17. Our friends at BINP in Novosibirsk are working on MC simulations of forward PID, and evaluating the pros of having the extra information, and cons of the extra material.
They are also doing serious R&D on aerogel and NaF radiators in proximity focusing geometries,
And studying cathode lifetime of various MCP PMT’s under different geometries.
May 9, 2007
SuperB Detector R&D
David Leith

18. Our friends ….
May 9, 2007
SuperB Detector R&D
David Leith

19. Cherenkov Photons in Time and Pixel domains
Cherenkov photons in time domain:
10 GeV/c electron beam data.
~ 200 pixels instrumented.
Ring image is most narrow in the 3 x 12 mm pixel detector.
Cherenkov ring in pixel domain:
Burle
Burle
Hamamatsu H-8500
Hamamatsu H-9500
Burle
Burle
May 9, 2007
SuperB Detector R&D
David Leith

20. Color tagging by measurement of photon propagation time
f(l)
vgroup = c0 / ngroup = c0 / [nphase – λ· dnphase / dλ]
t = TOP = L / vgroup = L [nphase – λ· dnphase · dλ ] / c Time-of-Propagation
dt/L = dTOP/L = l dl * | - d2n/dl2 | / c0
dt is pulse dispersion in time, length L, wavelength bandwidth dl, refraction index n(l)
We have determined in Fused Silica: dt/L = dTOP/L ~ 40ps/meter.
Our goal is to measure the color of the Cherenkov photon by timing !
May 9, 2007
SuperB Detector R&D
David Leith

21. Conclusions
We have demonstrated that we can correct the chromatic error of qC
This is the first RICH detector which has been able to do this.
Expected N0 and Npe is comparable to BaBar DIRC for MaPMT H-9500.
Expected improvement of the PID performance with 3x3mm pixels: ~20-30% compared to BaBar DIRC for pi/K separation, if we use H-9500 MaPMT.
The main defense against the background at Super-B is to make (a) the expansion volume much smaller, which is possible only with highly pixilated photon detectors, and (b) use of faster detectors.
Next test beam run: Add (a) ADC-based pixel interpolation, (b) 2-nd hodoscope after a bar, (c) ASIC-based readout on one MCP-PMT allowing a measurement of time and pulse height, (d) test of the TOF detector.
May 9, 2007
SuperB Detector R&D
David Leith

22. Timing at a level of s <15ps can start competing with the RICH techniques
Example
of various
Super-B
factory
PID designs:
Calculation
done for
Flight Path
Length = 2m
Recent progress in the TOF technique is driven by these advances:
(a) fast Cherenkov light rather than a scintillation, (b) new detectors with small transit time spread sTTS, (c) fast electronics, and (d) new fast laser diodes for testing.
May 9, 2007
SuperB Detector R&D
David Leith

23. Conclusions Our present best results with the laser diode:
- s ~ 12 ps for Npe = (expected from 1cm thick Cherenkov radiator).
- s TTS < 26 ps for Npe ~ 1.
- Upper limit on the MCP-PMT contribution: s MCP-PMT < 6.5 ps.
- TAC/ADC contribution to timing: s TAC_ADC < 3.2 ps.
- Total electronics contribution at present: s Total_electronics~ 7.2 ps.
(One has to be aware that the time-walk, due to variation of Npe,
has to be corrected).
May 9, 2007
SuperB Detector R&D
David Leith

24. Electromagnetic Calorimeter
                          
May 9, 2007
SuperB Detector R&D
David Leith

25. Electromagnetic Calorimeter
You will hear more from David Hitlin on this work.
He and Ren-Yuan Zhu are well supported at Caltech
by a DOE Detector Development grant.
Good LSO crystals are being fabricated, in production mode, by the Sichuan Institute of Piezoelectric and Acoustic-optic Technology (SIPAT), of good physical size, (120 mm X 80 mm), and a a fair price
( $ US 15 per cc).
One 60 mm X 250 mm crystal has been recently
made for SuperB.
May 9, 2007
SuperB Detector R&D
David Leith

26. SIC BGO CPI LYSO Saint-Gobain LYSO CTI LSO BGO, LSO & LYSO Samples
2.5 x 2.5 x 20 cm (18 X0) Bar
SIC BGO
CPI LYSO
Saint-Gobain LYSO
CTI LSO
May 9, 2007
SuperB Detector R&D
David Leith

27. LSO/LYSO ECAL Performance
Less demanding to the environment because of small temperature coefficient.
Radiation damage is less an issue as compared to other crystals.
A better energy resolution, (E)/E, at low energies than L3 BGO and CMS PWO because of its high light output and low readout noise:
2.0
0.5
.001/E
May 9, 2007
SuperB Detector R&D
David Leith

28. Muon system  
You will hear a talk this afternoon from, Gianluca Cavoto on a MINOS-type scintillator detector, more suited to the
high rate environment than the present gas chambers used in BaBar.
May 9, 2007
SuperB Detector R&D
David Leith

29. We will hear from each of the groups
So much for the overview of the detector R&D work, on specific systems;
We will hear from each of the groups
doing the work in the next parallel
session.
I would like to spend a moment now on
how the group might self organize for
the R&D, as a ‘provocation’ to assist
the parallel session discussion on this topic.
May 9, 2007
SuperB Detector R&D
David Leith

30. How will the R&D be organized, and funded and
reviewed/guided                          and
finally choices be made ?
May 9, 2007
SuperB Detector R&D
David Leith

31. [i.e. scientists in each region will approach their own agencies and
I believe that the R&D activities should proceed, at least for the next year, and
until there is a fully formed, and well supported, collaboration – under local financial support
[i.e. scientists in each region will
approach their own agencies and
propose support for the R&D that
they wish to pursue].
May 9, 2007
SuperB Detector R&D
David Leith

32. I think that it would be useful to SuperB
to set up a high level review
committee that looks at the
SuperB detector technical needs,
and
to provide a priority list of R&D
topics – both for the experiment,
and for the supporting agencies
[as we did in the beginning of BaBar].
May 9, 2007
SuperB Detector R&D
David Leith

33. I believe it would be helpful - * if this committee planned a regular
review of progress of the R&D
activities,
* performed a high level overlook
of the machine backgrounds to
be expected, and of the technical
needs of the experiment, and …
* provide advice to the SuperB
collaboration leadership.
May 9, 2007
SuperB Detector R&D
David Leith

34. Eventually, there will be a formal collaboration structure, with its
own governance, that will enable
the required choices and decisions
to manage the R&D program.
May 9, 2007
SuperB Detector R&D
David Leith

35. backup slides
May 9, 2007
SuperB Detector R&D
David Leith

36. Motivation to develop a new DIRC at Super-B
Goal:
- Super-B will have 100x higher luminosity
Backgrounds are not yet understood, but
they would scale with the luminosity if they
are driven by the radiative Bhabhas
DIRC needs to be smaller and faster:
Focusing and smaller pixels can reduce the expansion volume by a factor of 7-10 !
Faster PMTs reduce a sensitivity to background.
Additional benefit of the faster photon detectors:
- Timing resolution improvement: s ~1.7ns (BaBar DIRC) -> s 150ps (~10x better)
which allows a measurement of a photon color to correct the chromatic error of qc.
Focusing mirror effect:
Focusing eliminates effect of the bar thickness (contributes s ~ 4 mrads in BaBar DIRC)
However, the spherical mirror introduces an aberration, so its benefit is smaller.
May 9, 2007
SuperB Detector R&D
David Leith

37. qC resolution and Chromatic correction
All pixels:
3mm pixels only:
Correction off:
Correction on:
Correction off:
Correction on:
s ~ 5.0 mrad
sChrom +
sPixel
s ~ 5.1 mrad
The chromatic correction starts working for Lpath > 2-3 meters due to a limited timing resolution of the present photon detectors. The maximum likelihood technique does better for short Lpath than other methods
Holes in the uncorrected distributions are caused by the coarse pixilization, which also tends to worsen the resolution. In the corrected distributions this effect is removed because of the time correction.
Smaller pixel size (3mm) helps to improve the Cherenkov angle resolution; it is our preferred choice.
May 9, 2007
SuperB Detector R&D
David Leith

38. Crystal Density: Radiation Length
1.5 X0 Cubic Samples:
Hygroscopic Halides
Non-hygroscopic
CsI CsI(Na) CsI(Tl) NaI(Tl)
PWO LSO LYSO BGO CeF BaF2
BaBar CsI(Tl)
Full Size Crystals:
BaBar CsI(Tl): 16 X0
L3 BGO: 22 X0
CMS PWO(Y): 25 X0
L3 BGO
CMS PWO
May 9, 2007
SuperB Detector R&D
David Leith

39. Scintillation Light Decay Time
Recorded with Agilent 6052A digital scope
Fast Scintillators Slow Scintillators
LSO
LYSO
May 9, 2007
SuperB Detector R&D
David Leith

40. Light Output & Decay Kinetics
Measured with Philips XP2254B PMT (multi-alkali cathode)
p.e./MeV: LSO/LYSO is 6 & 230 times of BGO & PWO respectively
Fast Scintillators Slow Scintillators
LSO
LYSO
May 9, 2007
SuperB Detector R&D
David Leith

41. LSO/LYSO ECAL Performance
Less demanding to the environment because of small temperature coefficient.
Radiation damage is less an issue as compared to other crystals.
A better energy resolution, (E)/E, at low energies than L3 BGO and CMS PWO because of its high light output and low readout noise:
2.0
0.5
.001/E
May 9, 2007
SuperB Detector R&D
David Leith

42. Mass Produced Crystals
NaI(Tl)
CsI(Tl)
CsI
BaF2
BGO
PWO(Y)
LSO(Ce)
GSO(Ce)
Density (g/cm3)
3.67
4.51
4.89
7.13
8.3
7.40
6.71
Melting Point (ºC)
651
621
1280
1050
1123
2050
1950
Radiation Length (cm)
2.59
1.86
2.03
1.12
0.89
1.14
1.38
Molière Radius (cm)
4.13
3.57
3.10
2.23
2.00
2.07
Interaction Length (cm)
42.9
39.3
30.7
22.8
20.7
20.9
22.2
Refractive Index a
1.85
1.79
1.95
1.50
2.15
2.20
1.82
Hygroscopicity
Yes
Slight No
Luminescence b (nm)
(at peak)
410
550
420
310
300
220
480
425
402
440
Decay Time b (ns)
230
1250 30 6
630
0.9 10 40 60
Light Yield b,c (%)
100
165
3.6
1.1 36
3.4 21
0.29
.083 83
d(LY)/dT b (%/ ºC)
-0.2
0.3
-1.3
-0.9
-2.7
-0.1
May 9, 2007
SuperB Detector R&D
David Leith

43. Expected final performance at incidence angle of 90o
Focusing DIRC prototype bandwidth:
Prototype’s Npe_measured and Npe_expected are consistent within ~20%.
Hamamatsu H-9500 MaPMTs:
We expect N0 ~ 31 cm-1, which in turn gives Npe ~ 28 for 1.7 cm fused silica bar thickness, and somewhat better performance in pi/K separation than the present BaBar DIRC.
Burle-Photonis MCP-PMT:
We expect N0 ~ 22 cm-1 and Npe ~ 20 for B = 0kG.
BaBar DIRC design:
N0 ~ 30 cm-1 and Npe ~ 27.
Expected performance of a final device:
May 9, 2007
SuperB Detector R&D
David Leith