1. R&D for HCAL detectors at SLHC
By Y. Onel
CMS HCAL Meeting
Oct 16th-18th, 2003
Iowa City, IA

2. SLHC R&D technology (I) – Iowa/Fairfield/Boston
The HF detector at LHC has high-OH core, high NA, hard plastic cladding, QP fibers (quartz core plastic cladding)
Iowa group has tested fibers at LIL CERN 500 MeV electrons NIM A490 (2002) 444
The HF detector will receive about 100 Mrad/year at eta=5 with accumulated dose 1-2 Grad/10 years

3. SLHC R&D technology (I) – Iowa/Fairfield/Boston
The HF region will have much higher doses than LHC environment (1-2 Grad/year and about 20 Grad/10 years)
For high radiation doses must use no organic materials
We will test special quartz fibers with quartz cladding. These fibers are Silica/Silica, High-OH, UV enhanced, QQ (Quartz core/ Quartz cladding) with different type of buffer materials (Acrylic, Polymide, Aluminum) with different diameters (300, 600, and 800 micron)
Fibers will be given 5 x 1017 n/cm2, about 20 Grad (neutrons with energy > 0.1 MeV) in IPNS (Intense Pulsed Neutron Source) at Argonne National Laboratory
The range of Grad will also be available at this facility.
We will test the induced attenuation vs wavelength, transmission of Xe light in the nm range after irradiation. Also measure the tensile strength before and after the irradiation.
These measurements will be important for SLHC R&D for HCAL, HE, HF, ZDC, & CASTOR forward detectors.

4. SLHC R&D technology (I) – Iowa/Fairfield/Boston

5. SLHC R&D technology (I) – Iowa/Fairfield/Boston

6. QQ fiber Transmission Measurements
Transmission of Xe light through QQ fibers before radiation
Measured at Iowa’s HEP lab using micro-spectrometer

7. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Goals:
Determine if optical fibers are capable of functioning in a radiation environment 10 times the present CMS detector levels.
If yes, then explore what fiber designs would be best for the CMS detector upgrade.
Test candidate fiber materials –core, clad and buffer to determine suitable materials.
Fabricate/Purchase test fibers with materials from step 3.
Test candidate fibers for radiation hardness, mechanical and optical performance before and after irradiation.
Develop preliminary fiber specifications

8. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Fiber Designs – conduct review of the fiber designs suitable for the CMS application. From this review, select the focus of the design and testing activities. Focus should be on the fiber design offering the most chances of success. As can be seen from the list below there are way too many fiber designs to test all.
Step Index Multimode -
Silica Core/Doped Silica Clad – QQ
Std QQ – Std Preforms
Multiple preform sources
Background known
Modified Silica Core/Doped Silica Clad – MQQ
Modified Preforms
Improve rad hardness?
Improved mfg cost?
Natural Quartz Core/Doped Silica Clad –NQQ
Lower cost
Rad hardness?
Strength?

9. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Natural Quartz Core/Polymer Clad – NQP
Lower cost
Rad hardness?
Strength?
Air Clad Multimode
Unknown performance – multimode case
Theory still in early stages for SM
SM where all results obtained
Light Guiding Capillary – LTSP
Same materials as QQ
Hole in core allows addition of light generation material
New fiber unknown rad hardness
Costs similar to QQ

10. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Graded Index Multimode –
Std GI poor radiation performance, small cores (50um)
GI Fibers not suitable for CMS application
Single Mode –
Std SM - Radiation performance unknown, extremely small cores (<10um)
Air Clad – also known as: Holey Fibers, Photonic Band Gap Fibers, Photonic Crystal Fibers, Micro Structured Fibers – same problems as std SM
SM Fibers not suitable for CMS application

11. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Optical Fiber Materials – review possible materials for material testing (Radiation testing), obtain bulk and fiber samples for tests. Evaluate test results and select candidate materials for fiber fabrication.
Core Materials
Evaluate various Silica Materials
Evaluate various Natural Quartz Materials
Other materials – sapphire (expensive)?
Clad Materials
Research cladding materials – fluorine offers best radiation and NA results
Evaluate Fluorine doped materials and others identified above
Buffer Materials
Evaluate various polymer materials – polyimide, acrylate, silicone, plus extruded polymers
Evaluate various metal materials – Aluminum, Others?

12. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Fabrication/Purchase Candidate Fibers – purchase standard off the shelf candidate fibers plus fabricate specialty fibers for testing.
Standard fibers
Specialty fibers from std preforms
Specialty fibers from special preforms
Design/Specify Preform
Draw Preform into fiber

13. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Materials Testing – conduct radiation testing on candidate optical fiber materials with the University of Iowa and Argon National Labs. Goal is to select materials that can survive future CMS radiation levels. Bulk as well as fiber samples will be evaluated in multiple tests. Evaluation of the materials will include mechanical strength and optical performance.
Bulk Material Testing
Preliminary Fiber Testing
Candidate Fiber Testing

14. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Optical Fiber Parameters – develop preliminary fiber specification around the following: (use present fiber specification as starting point)
Dimensions/Tolerances
Design/Materials
Optical Attenuation
Mechanical Strength
Handling
Termination QA

15. Iowa Polymicro New Rad-hard Quartz fiber/plate project
Optical Fiber Testing – conduct optical fiber testing on preliminary and candidate fibers (before and after radiation testing).
Optical Tests – Attenuation and NA
Mechanical Tests – Tensile, Bend, Proof Test, Flex, Abrasion
Termination Tests – Epoxy bonding, Cleaving, Polishing
Radiation Tests – University of Iowa and Argonne National Labs

16. Iowa Polymicro New Rad-hard Silica & Quartz plate
Qty Price
Fused Silica Plates, 100mm X 200mm+/-.5mm X 2.0mm+/-0.1mm, 80-50,
100 $180ea
scribed edges no bevels
1000 $175ea
Vycor Plates,100mm X 200mm+/-.5mm X 2.0mm+/-0.1mm, 80-50,
100 $120ea
1000 $105ea

17. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Hadron
The green is solid metal. Detectors that sample the shower are shown in blue. Detector near front end is for EM shower
Some forward-angle calorimeters for the LHC will receive huge amounts of radiation, ~100 Grad.
Need detector to be fast, simple, and radiation hard.

18. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Three flat plates, separated by 2 mm
Middle plate at high voltage
Outer plates hold atmospheric pressure
Filled with torr of a suitable gas
Timing resolution better than 300 ps
Will test energy and time resolution at the Advanced Photon Source (APS) at Argonne
A simple and reliable device for sampling showers from hadrons and photons.
For highest radiation levels must be made with no organic materials

19. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
This PPAC detector concept can be developed as a candidate for luminosity monitor, HF and ZDC at SLHC.

20. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Preliminary – Electronics Timing resolution for 6 MeV Alpha particles
Used mixed alpha source from 228Ra Similar to signal from 300 GeV hadron shower

21. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Preliminary – Electronics Timing resolution

22. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Preliminary – Electronics Energy resolution

23. SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Preliminary – Electronics Energy resolution

24. Planned tests with double PPAC
SLHC R&D technology (II) Iowa PPAC - a radiation hard detector
Planned tests with double PPAC
Test with EM showers using 80 ps bunches of 7 GeV electrons from the Advanced Photon Source, at Argonne National Laboratory
Test with low energy hadron showers using the 120 GeV proton test beam at Fermilab

25. PPAC vs. Scintillating tile
A radiation hard PPAC could be made as a drop in replacement for a scintillating tile in HE.
It would fit in the same space and produce a similar (but faster) signal.

26. A Dynode Stack is an Efficient High Gain Radiation Sensor
SLHC R&D technology (III) – Iowa/Fairfield Secondary Emission Sensor Modules for Calorimeters
Basic Idea:
A Dynode Stack is an Efficient High Gain Radiation Sensor
High Gain & Efficient (yield ~1 e/mip for CsSb coating)
Compact (micromachined metal<1mm thick/stage)
Rad-Hard (PMT dynodes>100 GRads)
Fast
Simple SEM monitors proven at accelerators
Rugged/Could be structural elements (see below)
Easily integrated compactly into large calorimeters
low dead areas or services needed.
SE Detector Modules Are Applicable to:
- Energy-Flow Calorimeters
- Polarimeters
- Forward Calorimeters

27. “A Flat PMT without a Photocathode”:
SLHC R&D technology (III) – Iowa/Fairfield Secondary Emission Sensor Modules for Calorimeters
Basic SEM Calorimeter Sensor Module Form:
“A Flat PMT without a Photocathode”:
- The photocathode is replaced by an SEM film on Metal.
Stack of 5-10 metal sheet dynodes in a metal “window”-ceramic wall vacuum package about 5-10 mm thick x cm square, adjustable in shape/area to the transverse shower size.
Sheet dynodes/insulators made with MEMS/micromachining techniques are newly available, in thicknesses as fine as ~0.1 mm/dynode
Ceramic wall thickness can be ~2mm, moulded and fired from commonly available greenforms (Coors, etc.)
Outer electrodes (SEM cathode, anode) can be thick metal, serving as absorber and structural elements.