HE CALORIMETER DETECTOR UPGRADE R&D Y. Onel for University of Iowa Fairfield University University of Mississippi

Outline The Problem, and proposed solution. Best radiation hard quartz option. First results from Quartz Plate Calorimeter Prototype – I New direction for the QPCAL-II –Light enhancement options: Light enhancement options: P-Terphenyl (PTP), ZnO. Raddam on PTP –PIN Diode, APD, SiPMT readout options.

The “Problem” and the “Solution” As a solution to the radiation damage problem in SuperLHC conditions, quartz plates are proposed as a substitute for the scintillators at the Hadronic Endcap (HE) calorimeter. Quartz plates will not be affected by high radiation. But the number of generated cerenkov photons are at the level of 1% of the scintillators. Rad-hard quartz –Quartz in the form of fiber are irradiated in Argonne IPNS for 313 hours. –The fibers were tested for optical degradation before and after 17.6 Mrad of neutron and 73.5 Mrad of gamma radiation. –Polymicro manufactured a special radiation hard anti solarization quartz plate.

QPCAL-I Design and Construction R&D results and the initial model shaped the prototype. The CMS NOTE summarizing the R&D studies is submitted collaboration. The final design: 20cm x 20cm, 20 layers, 70 mm iron, 5 mm thick quartz grooved. It is portable for tests at CERN, Fermilab, and Iowa. The signal is read by Hamamatsu R7525 PMTs. The fibers are 1mm diameter Saint Gobain wavelength shifting fibers. They absorb photons down to 280 nm, and emit 435 nm. The fibers go ~20 cm out of the quartz.

QPCAL-I Plate Frames Fibers The quartz plates are put into an aluminum frame. All quartz plates with fibers are wrapped with Tyvek and black tape. Then they are put into a frame, and wrapped again to make them light-tight.

QPCAL-I Design Details Alternating PMT positions allow the plates to be tested with less iron between them. For the electron beam we set the absorber thickness to 2 cm. 1 cm iron plates are purchased for use at CERN for electron beams. We put absorbers and plates on a rail for flexible positioning.

QPCAL-I Design Details During the R&D studies, we developed our own DAQ with NIM, CAMAC and LabView. But it is not fast enough for the 30 channels of the prototype. New DAQ is built with VME units. We built 3 Ten Channel Amplifiers: –Gain: 30 dB (32 times) –Rise Time: < 2 nsec –Fall Time: < 2 nsec –Noise Figure: ~ 3 dB (~ 10uV) –Bandwidth: 500 MHz –Input SWR: 2:1 (0 – 200 MHz) –Output SWR: < 2:1 (0 – 500 MHz) –Maximum Output: 2 volt peak –Isolation: > 80 dB (0 – 500 MHz) between any two channels

QPCAL-I Geant4 Simulation Model We modeled the prototype with Geant4. The simulation efforts keep developing. We simulate the test beams and possible design changes.

QPCAL-I Geant4 Simulations Simulated detector response linearity for electrons and hadrons.

Finally QPCAL-I is complete… 20 quartz plates, one at each layer. 10 HE scintillator plates, one every other layer. We constructed a table to support the entire rail system containing the calorimeter prototype during the Fermilab tests. At M-Test we got 120, and 66 GeV beam, we use 5cm thick iron absorbers.

CERN Test Beam QPCAL-I At CERN we used 2 cm thickness of iron absorber for the electron beam. 7 cm of absorber is used for Pion beam - Movable table was used for the setup. It allowed us to do surface scan at 100 GeV electron and 80 GeV pion beams. - We got electron beam at 20, 50, 80, 100 GeV. - Pion beam at 20, 50, 80, 100, 150, 200, 300, and 350 GeV.

QPCAL-I Electron Response Electron Response Profiles for Quartz.

QPCAL-I Surface Uniformity QPCAL – I is designed to have superior surface response uniformity. Beam size and leaking shower creates non-uniformities.

QPCAL-I Pion Response QPCAL-1 has very good hadronic resolution, for comparison purposes we include ZDC signal For the same energy. ZDC-HADRONIC Response for 300 GeV Pion O.Grachov et al. QPCAL-1 50 GeV Pion 300 GeV Pion

QPCAL-I Response Linearity Hadronic Response Linearity Elecromagnetic Response Linearity

QPCAL-I Energy Resolutions Hadronic Resolution Electromagnetic Resolution

New Directions QPCAL-I analysis, and simulations are about to finish, we are preparing the CMS NOTE. QPCAL-1 also has 10 scintillator plates on every other layers, this “hybrid” structure can improve the detector capabilities even more. We have not shown any scintillator result on this talk. QPCAL-1 proved that quartz plate cerenkov calorimeter is a very good candidate to replace HE calorimeter during SLHC era. Now, we are focused on eliminating WLS fibers and Hamamatsu PMTs from the design, this will be done by; –Increase the light yield with radiation hard scintillating/WLS materials; PTP, PTP and RTV615 mix, and ZnO. RTV 615 which is a 2 component UV clear silastic-type epoxy. –Readout will be done directly from the plate via APD, or SiPMT. During the previous R&D studies we have tested PTP for radiation hardness. During the preliminary tests we observed up to 40% light improvement with ZnO and PTP.

PTP Raddam Tests PTP irradiated at Indiana University Cyclotron Facility, in May '06 We reached 10 Mrad level with 200 MeV protons. Samples diluted in Toluene and subjected to C14  source. Counting rates measured vs concentration. Little damage observed when compared to unirradiated sample. 10 MRad 200 MeV protons

PTP and Zinc Oxide The initial tests on PTP and ZnO Showed promising light improvement.

Quartz Plates with ZnO and PTP At Fermilab Lab7, we are covering 3 quartz plate with PTP by evaporation. We also cover 3 quartz plates with ZnO (3% Ga doped), by RF sputtering. Fermilab Lab7, thin film sputtering system and guns.

NEW READOUT OPTIONS We have 5 Hamamatsu S8141 APDs (CMS ECAL APDs) ready to be used. The circuits have been build at Iowa. These APDs are known to be radiation hard. (NIMA 504, (2003) We have also purchased 2 other type of Hamamatsu APDs: S5343, and S K

NEW READOUT OPTIONS We have purchased 2 types of PIN-Diodes; Hamamatsu S5973 and S They are gettng ready to be tested this summer. We are also trying to acquire SiPMTs. Compared to the others, the SiPMTs have lower noise level. For all of these readout options we designed different amplifier approaches: 50 Ohm amplifier. Transimpedance amplifier. Charge amplifier. 50 Ohm Amplifier circuit design.

NEW READOUT OPTIONS The speed of the readout is essential. The pulse width of the optical pulses from the scintillator limits the selection of photodiode or APD used. A bandwidth of 175 MHz is equivalent to a rise and fall time of 1.75 nsec. TopologyPriceSpeed (Rise time)Input Equiv. NoiseComments Photodiode with 50 Ohm amplifier LowFast (< 1 nsec) ~ 50 pW/ √ Hz Simple circuitry Photodiode with fast transimpedance amplifier LowModerate (< 3 nsec) ~ 10 pW/ √ Hz Simple circuitry APD with 50 Ohm amplifierModerateFast ~ 250 fW/ √ Hz (Gain of 50) Drift with temperature High voltage Moderate complexity for HV APD gain from 25 to 150 APD with 50 Ohm amplifierModerateModerate (<3 nsec) ~ 50 fW/ √ Hz Drift with temperature High voltage Moderate complexity for HV APD gain from 25 to 150 Silicon PMTModerateFast ~.1 fW/ √ Hz Simple to moderate complexity

CONCLUSION So far we have done extensive R&D studies on efficient cerenkov light collection from Quartz plates using WLS fibers. These efforts have been summarized in first CMS Note. The QPCAL-I prototype has been tested at CERN, and shows very good potential as a Hadronic, and Electromagnetic calorimeter. The detailed analysis report is going to be in Second Note. Now, we are focused on eliminating the WLS fibers and current PMTs from the design, and implementing light enhancement tools, as well as “on plate” readout. For this purpose we have prepared PTP, and ZnO covered quartz plates. PIN diodes, APDs, and SiPMTs are going to be evaluated as readout devices. This summer we are going to test all of these options at bench tests and test beams. As always these studies will be supported by GEANT4 simulations. The QPCAL-II is going to be built in light of these studies.

Backup Slides

PPP-1 Resolution Plots