1. Towards a realistic Scintillator HCAL with SiPM read-out
Felix Sefkow
CALOR08, Pavia
May 30, 2008

2. From proof-of principle to reality
See talks by
Erika Garutti (test beam results)
Angela Lucaci (Calibration)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

3. Collaborating institutes
Czech R.: Prague
France: LAL Orsay
Germany: DESY, Hamburg, Heidelberg, MPI Munich, Wuppertal
Japan: Kobe, Shinshu
Russia: JINR; ITEP, LPI, MEPHI Moscow
UK: Cambridge, Imperial C, UCL, RAL
US: Northern Illinois
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

4. Towards a Realistic Scintillator HCAL with SiPMs
Outline
Physics requirements and design goals
A compact design with integrated sensors and electronics
For the electronics itself, see subsequent talks by
Christophe De La Taille (front end ASICs)
Valeria Bartsch (DAQ)
Common design for ECAL, scint and gas HCAL
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

5. Towards a Realistic Scintillator HCAL with SiPMs
Calorimetry at the ILC
√s (e+e-) =0.5-1 TeV
Multi-jet events, typically:
Ejet ~ 50 … 150 GeV
Ehadron ~ 1 … 100 GeV
An imaging HCAL for particle flow reconstruction
Two-particle separation
Hadronic energy resolution
High longitudinal and transverse granularity
Software compensation
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

6. Towards a Realistic Scintillator HCAL with SiPMs
Design goals
Novel multi-pixel Geiger mode photo-diodes (SiPMs)
B-field proof, small, affordable
High granularity with scintillator at reasonable cost
photo-sensors integrated
Opens revolutionary design options:
embedded electronics and calibration system for minimal dead zones
thin readout gap
Granular, compact, hermetic
(DESY)
(ITEP)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

7. Towards a Realistic Scintillator HCAL with SiPMs
Tile granularity
Recent studies with PFLOW algorithm, full simulation and reco.
1x1
3x3
5x5
10x10
50M 5M 2M
500k
Confirms earlier studies for test beam prototype
3x3 cm2 nearly optimal
M.Thomson (Cambridge)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

8. Geometry, optimization, integration
Presently starting new round of detector optimization, using detailed simulations and state-of-the art reconstruction algorithms
Baseline: stainless steel, square tiles
Also considered: brass or lead
Scintillator striplets
R&D and integration issues are largely independent on details of final geometry
Sensors and tiles
Ultra-low power electronics, interfaces
Mechanical structure
M.Thomson (Cambride))
A scintillator based calorimeter
with embedded sensors and
electronics has not been built before
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

9. Tile sensor systems with WLS fibre
Present test beam system
5mm thick tile with fibre, MEPHI/ PULSAR SiPM, 15 pixels/MIP
Several new options: reduce to 3 mm thick tiles
Hamamatsu MPPC-1600
MRS APDs (CPTA)
M.Danilov (ITEP)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

10. Tile sensor direct coupling
Possible with blue-sensitive sensors
Hamamatsu MPPC 1600 (400)
Obtain about 7 (11) px/MIP from 5 mm tiles; low noise
 increase area
Need to restore uniformity
Some addal light cost
Other proven option: strips
CALICE SciW ECAL
N.D’Ascenzo (DESY)
Tile 30x30x5 mm3
1600 px
V.Zutshi (NIU)
D.Jeans (Kobe)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

11. Towards a Realistic Scintillator HCAL with SiPMs
Tile PCB coupling
Scintillator photo-sensor system has to match electronics PCB tolerances
Several options
Mega-tiles (easier assembly, but some optical cross-talk
New: idea “lego” tiles with alignment pins
30x30x3mm3
Other option: surface-mounted sensors on PCB
Different integration chain
V.Rusinov (ITEP)
SiPMs
P.Rubinov (FNAL)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

12. Integrated layer design
Sector
wall
Reflector Foil
100µm
Polyimide Foil
PCB
800µm
Bolt with inner
M3 thread
welded to bottom
plate
SiPM
Tile
3mm
HBU Interface
500µm gap
Bottom Plate
600µm
ASIC
TQFP-100
1mm high
Top Plate
600µm steel
Component Area:
900µm high
HBU height:
6.1mm
(4.9mm without covers => absorber)
Absorber
Plates
(steel)
Spacer
1.7mm
fixing
DESY
M.Reinecke (DESY)
integrated
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

13. Optical calibration system
M.Reinecke (DESY)
SiPMs, MPPCs are self-calibrating
Ph.e. peak distance ~ gain
Embedded LEDs
electronic signal distribution
tested, no cross-talk to sensors seen
To be optimized: dynamic range, LED uniformity
Alternative: central driver and optical signal distribution
S.Weber
(Wuppertal)
I.Polak (Prague)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

14. New ASIC on the test benches
Auto-triggering and time measurements
ADC and TDC integrated
Power pulsing, low (continuous) power DAC ns
50-100ns
Gain selection
4-bit threshold adjustment
10-bit DAC
15ns
DAC output
HOLD
Slow Shaper
Fast Shaper
Time measurement
Charge measurement
TDC ramp 300ns/5 µs
12-bit Wilkinson
ADC
Trigger
Depth 16
Common to the 36 channels
8-bit DAC
0-5V
Low gain Preamplifier
High gain Preamplifier
Analog memory
15pF
1.5pF
0.1pF-1.5pF
Conversion
80 µs
READ
Variable delay IN
Discri
Gain
Flag TDC
Analog output
L.Raux (LAL)
R.Fabbri (DESY)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

15. Barrel HCAL architecture
AHCAL Slab
6 HBUs in a row
HBU
HCAL Base Unit
12 x 12 tiles
SPIROC
4 on a HBU
HEB
HCAL Endcap Board
Hosts mezzanine modules:
DIF, CALIB and POWER
HLD
HCAL Layer Distributor
Front end ASICs embedded
Interfaces accessible
1/16 of barrel half
Power:
40 µW / channel
Heat:
T grad. 0.3K/2m
Time constant: 6 d
P.Goettlicher (DESY)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

16. Towards a Realistic Scintillator HCAL with SiPMs
Details
Interface Prototype
M.Reinecke (DESY)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

17. Towards a Realistic Scintillator HCAL with SiPMs
Mechanical structure
Aggressive design: 3mm walls
No additional spacers
FEM calculation with sector details for full barrel
Max displacement 2mm, stress 
Integration with cryostat and ECAL
K.Kschioneck (DESY)
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs

18. Towards a Realistic Scintillator HCAL with SiPMs
Conclusion
A technical design for a highly granular scintillator HCAL
Meets particle flow requirements
1000 tiles / m2, individually read out
Latest generation SiPMs, MPPCs
Embedded photo-sensors, ASICs, calibration system
No fibres, no HV lines, no cooling pipes
Compact mechanical design
Thin r/o gap, no cracks, ~99% instrumented
Build it:
Electronics prototype with tiles and r/o chain in 2008
Layer demonstrator in 2009
Felix Sefkow CALOR08, Pavia, May 30, 2008
Towards a Realistic Scintillator HCAL with SiPMs