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

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

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 10-50 Grad will also be available at this facility. We will test the induced attenuation vs wavelength, transmission of Xe light in the 350-800 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.

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

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

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

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

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?

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

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

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?

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

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

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

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

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

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.

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 10-40 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

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.

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

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

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

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

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

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.

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

“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 10-25 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.