Summary of Calorimetry R & D

1. Summary of Calorimetry R & D DongHee Kim Kyungpook National University(Korea) ACFA8 Workshop

2. Presentations at this workshop • Not many talks at this workshopbut R & D efforts made progress a lot and will go on continuously !! • TiCAL • SiPM & MPC R & D : Kawagoe, Iba(Japan) • Scintillator Strips R & D : Jacosalem (Japan) • Extruded Scintillator R & D : Oh (Korea) • SiCAL • Test beam results & MC : Nam(Korea)

3. Fine segmentation scintillator Read out by photon sensor -> Study of photon sensor Basic Configuration (TiCAL) • Present design of GLD Calorimeter • We might need smaller segmentation calorimeter • 10x40x2mm strip type scintillator X, Z-layer strip scintillator : 10x200x2mm Tile-layer : 40x40x1mm Strip scint & SiPM(or MPC) R & D Studies important !

4. Scintillater R & D • Casted Scintillator • Light Reflection • Groove effects(position et al…) • Cell(or Block) type scintillater responses • Extruded scintillator • Light Yield • position dependence

5. 3M radiant mirror film Teflon White paint with teflon White paint Aluminum evaporation Black sheet Gold 3M radiant mirror film Teflon White paint with teflon White paint Aluminum evaporation Black sheet Gold Systerror Light Reflections • 3M radiant mirror film has the greatest pulse height. • There is a trend that pulse height slightly increases with sensor’s length for 3M radiant mirror film and Teflon. E. Jacosalem (Niigata)

6. Results cont.. syst error 3M radiant mirror film Teflon White paint with teflon White paint Aluminum evaporation Black sheet • 3M radiant mirror film has greatest pulse height. • 3M radiant mirror film and teflon wrapped scintillators showed that good total reflection occurred when thin air gap is present between reflector and scintillator. E. Jacosalem (Niigata)

7. Results cont.. PMT 1.6mmΦ WLS_3Mmirror film 1.0mmΦ WLS_3Mmirror film 1.6mmΦ WLS_ Teflon 1.0mmΦ WLS_ Teflon measurement across the strip WLS fiber measurementalong the strip Keyhole Position Dependence along the Strip Scintillator (2.5 mm from the center) Position Dependence along the Strip Scintillator (2.5 mm from the center) Quite Uniform !! • Position dependence along the strip scintillator showed the uniformity of light transmission from the sensor to PMT. E. Jacosalem (Niigata)

8. Results cont.. Position Dependence across the Strip Scint (3M radiant film) 1.6mmΦ WLS ; source positioned @ 10 (bl) and 20mm (gr) from the far end small peaks 1.6mm 1mmΦ WLS ; source positioned @ 10mm (bl) and 20mm (r) from the far end Fiber diameter 1mm • ‘dip’ is 40% corresponds to scint. thickness(300microns) f0r 1.6mmΦ fiber • small peaks near the fiber (1.6mmΦ fiber) • no significant difference on pulse height values across the strip at 2 different locations (20mm and 10 mm from end) • light yield increases about 100% as fiber diameter is increased from 1.0mm to 1.6mm for 3M radiant mirror film. E. Jacosalem (Niigata)

9. Results cont.. 3M radiant mirror film Teflon Thickness Dependence of Block Type Scintillator for Digital Hadron Calorimeter • No peak observed at 8mm thick. • Pulse height almost proportional with scint thickness for 3M radiant mirror film. • Light output at 6mm is larger than that of strip scint (10x40x2mm) then the block scint is enough for digital hadron calorimeter. E. Jacosalem (Niigata)

10. Summary 1. 3M radiant mirror film : best for Light reflection 3. 100% more light with 3M film with 1.6mm fiber in comparison with 1mm fiber case. 4. Good uniformity on Position along the strip scintillator for 3M film and teflon. 5. ‘dip’ is40% corresponds to scint. thickness(300microns) for 1.6mmΦ fiber 6. Block type scintillator’s light yield is almost proportional to its thickness E. Jacosalem (Niigata)

11. Extruded Scintillator R & D Current R&D Status • At first, the pure polystyrene bar was produced without • PPO, POPOP • The mechanical process has been established • 2. At second, PPO and POPOP were mixed up with polystyrene •  The 1st scintillator was produced. • 3. Light yield was measured and compared with reference • scintillator Youngdo Oh (Kyungpook)

12. Extrusion Process All the work is done at one facility → reduces costs By removing its exposure to another high temperature cycle → reduces hits history of the product → eliminates an additional chance for scintillator degradation Youngdo Oh (Kyungpook)

13. 1.2 mm 2mm 1cm 4cm Die and Materials • Die profile • Mixture of dopants Polystyrene : 3 kg PPO : 1.3 % POPOP : 0.03% Youngdo Oh (Kyungpook)

14. First Batch from Misung chemical • At first, We try to produce polystyrene bar without PPO and POPOP to make sure the chemical and mechanical process. • TiO2 was coextruded to make reflector. • At 2005/5/17 , Misung launched extrusion for scintillator • The first product had big groove  die had minor problem • At 2005/6/9 , the excellent bars were produced. • At 2005/7/7, the 2nd bacth has PPO, POPOP. Youngdo Oh (Kyungpook) Evolution

15. Comparision of transparency Oxidation made the sample opaque because of production in air. Polysyrene bar Reference samples New samples Youngdo Oh (Kyungpook)

16. FAN IN-OUT Disc Logic unit Gate Generator 100 ns Delay VME readout Scintillator test setup • 5 reference samples and new samples with the same geometrical shape and size were used to compare light yield Typical cosmic ray From reference sample + WLS Youngdo Oh (Kyungpook)

17. Light Yield Measurement Trigger : random trigger (1000Hz) , Gate=150ns (amplifier used : x100 ) New sample New scintillator bars (5 samples) <ADC counts> = 225.9  24.9 Reference scintillator bars(5 samples) <ADC counts> = 534.8 56.9 ADC counts Reference sample Relative Light Yield of new samples shows 42.3% of reference samples Youngdo Oh (Kyungpook) ADC counts

18. Reference samples Average = 4.35 RMS = 0.39 A New samples Average = 1.59 RMS = 0.18 Sample ID Light Yield Measurement Pico ammeter is used Relative Light Yield of new samples shows ~40 % of reference samples’ one. Youngdo Oh (Kyungpook)

19. A A cm cm Light Yield Measurement Refernce sample New sample Youngdo Oh (Kyungpook)

20. Summary and Plan • First Polystyrene bar produced with PPO and POPOP  The mechanical process is established • Light yield measued for new and reference samples  new sample shows ~40% light yield of reference sample  low light yield because of oxidation in air • To avoid oxidation, we need to change process  under Nitrogen or vaccum • If we get good light yield, then we will change die to produce “thin” scintillator for tile calorimeter  thickness : 3mm , width : 1cm Youngdo Oh (Kyungpook)

21. Silocon Photomultipliers • SiPM : Russia • Currently used for prototype test etc.. • MPC(Multi-pixel Photon Counter): • Hammamatsu product • under R & D but lots progress made • main talks on this subject at this workshop

22. ＧＮＤ e- SiPM (Silicon Photomultiplier) :originally Russian made ・Number of pixels: 34 x 34 = 1156 ・Bias Voltage : 64～67.5V ・Gain is ～10^6 500mV 2ns ≒１ｍｍ Photoelectron peaks observed with an oscilloscope （using ORTEC 820A Fast Amp） ≒１ｍｍ Pictures of Russian SiPM Kiyotomo Kawagoe(Kobe)

23. Russian SiPM: Gain vs Temperature • Gain of R1156 is higher at lower temperature (consistent with semiconductor characteristics) • Gain variation between samples is large, as long as our small number of samples are concerned. -20C -10C 0C 10C 20C Kiyotomo Kawagoe(Kobe)

24. MPC 400pixels ~100um ~85um MPC 100pixels (10x10pixels) 2. New photon sensor --MPC-- • MPC :Multi pixels Photon Counter • Made by Hamamatsu Photonics and under development • Each pixel is in Geiger mode and as a whole pixels they worked in avalanche mode • Compact device • Works with much lower voltage than PMT • Suitable for wavelength shifter fiber • We have two types of MPC • 100pixels : 10x10pixels • 400pixels : 20x20pixels Sayata Iba(Niigata)

25. Hammamatsu MPC: Gain vs Temperature H100-1 H100-2 • Gain(H100) is larger than Gain(H400) in general. • MPC gain is higher at lower temperature. • At room temperature (20C), • Gain(H100) > 10^7 • Gain(H400) > 10^6 • The gain variation is very sensitive to bias voltage.  Accurate voltage control will be necessary for stable operation. H400-1 H400-2 -20C -10C 0C 10C 20C Kiyotomo Kawagoe(Kobe)

26. H100(MPC): Peaks up to ~40 photons can be observed. These data were taken by changing LED light intensity. Up to ~40 photon peaks can be observed. Excellent ! LED 4.5V×10ns LED 5.5V×10ns LED 6.5V×10ns LED 7.5V×10ns Kiyotomo Kawagoe(Kobe)

27. 48.9V 48.7V H100 absolute gain at room temperature (20C) • We made the measurement for a H100 sample (no amplifier is used). → H100 MPC’s gain increases as a function of bias voltage with its maximum gain ~ 2 x 10^7 at V_B >= 49.1V. • Peak distances at low bias voltage are not equal. → we would like to have better understanding ↑Gain Calculated from peak interval Gain vs Bias Voltage (Temperature 20C) Kiyotomo Kawagoe(Kobe)

28. 3. Setup of MPC measurement using laser system Logic readout YAG Laser MPC YAG Laser Wave length & power: 532nm (10mJ/cm2), 1064nm (20mJ/cm2) Filter : Laser intensity is down to10-8 Trigger : from Laser system Pulse width : <10nsec Laser beam minimum spot size : <2um Precision of laser position : ±2um MPC Output circuit Sayata Iba(Niigata)

29. ~85um ~30um ~35um Laser hitting area (smaller than 1pixel) 7. uniformity dependence of pixel to pixel • Injected laser single photon to each pixel and got response • Measurement conditions • MPC : 100pixels • Sensor bias : 49.0V • Laser wavelength : 532nm • Laser hitting area is smaller than 1pixel area • Measured points are 50points that are shown as gray area Measured points : 50points (Gray pixels) Sayata Iba(Niigata)

30. Pulse Height 1photon mean 0photon mean • Pulse height = 1photon mean value – 0photon mean value • Deviation of PH (RMS) : 10% • Laser long term fluctuation : ≦5% Pulse height vs Pixel position # of pixels Distribution of the PH Sayata Iba(Niigata)

31. Cross sectional view (Central part) Y-axis line-5+6 • Cross section of X-axis (line-5 + line-6) and Y-axis (line-5 + line-6) which are shown in previous slide • Central part of sensor Cutting X-axis line-5▲ + line-6▲ X-axis line-5 +6 Cutting Y-axis line-5▲ + line-6▲ Sayata Iba(Niigata)

32. Y-axis line-9+10 X-axis line-9 +10 Cross sectional view (Edge part) Cutting X-axis line-9▲ + line-10▲ • Cross section of X-axis (line-9 + line-10) and Y-axis (line-9 + line-10) • Edge of sensor • We can see that pulse height level and deviation look same as previous slide Cutting Y-axis line-9▲ + line-10▲ Sayata Iba(Niigata)

33. Summary • We are testing new silicon photon sensors which can be directly attached to WLS at scintillator end ; • SiPM and Hamamatsu MPCs • We have tested • Photon counting capability • Gain and noise rate at different bias voltage and temperature • Position dependence across the pixel to pixel(MPC only) • R&D of Hamamatsu MPC just started last year: • Very promising, but • A lot of things to do • Close communication between Hamamatsu and users (physicists) is very important. Kiyotomo Kawagoe (Kobe)

34. SiCAL R & D • Prototype beam test result • Comparison with Monte Carlo

35. Summary of Our Test Module Geometry • Total 20 layers = 20X with uniform layer thickness • Shower sampling at 19 layers with 2 sensors each layer. • 1mm gap between sensors • Aligned beam center to the center of a sensor 1mm inactive gap Effective RM :~ 45mm from volume ration of material RM 131mm X 115mm -> insufficient transverse shower containment No action taken for cooling the detector. Temperature level during test : ~35 to 40 deg Shinwoo Nam (Ewha)

36. CERN Beam Test Steps of Beam Test 1. Tune trigger time delay 2. Align detector by using movable table under the our detector 3. MIP calibration of all channels (using hadron beam (less spread) after removing all tungstens) 4. Data Run (electron 150,100,80,50,30,20,10 GeV hadron 150 GeV muon 150 GeV) random trigger mixed in the runs for pedestal monitor beam Thanks A. Malinine for the test beam line control Beam Test : CERN SPS H2 beam line for a week till Sep. 7 2004 Beam cycle 18.0 sec with 4.8 sec spill time beam line focus & existing trigger scintillators give beam spread of ~1 cm diameter Beam focus worse in muon beam Shinwoo Nam (Ewha)

37. Detector Response to Different Particles Random Trigger events (total pedestal) 50 GeV Electron Online Shower Profile Monitor Pedestal subtracted 50 GeV pion First Analysis : sum ADC counts of all channels No rejection of dead, noisy channels, No gain calibration applied 150 GeV Muon Shinwoo Nam (Ewha) Total ADC of an event / 640

38. Fitted curve to… 18 % / √E Geant Simulation total energy loss in silicon layers vs. electron beam energy dE/E vs. E MeV GeV GeV <20GeV> <50GeV> Shinwoo Nam (Ewha)

39. Energy Resolution Preliminary • Geant4 simulation of this setup taking into account only shower leakage gives 18%/√E. • Simulation with dead channels (~2%),noisy channels (~10%), ADC unstable(~10%) : 21%/√E. • Further analysis needed to study the influence of beam spread,insufficientgaincalibration, and readout channel cross-talks. Fit curve : 29%/√E dE / E (%) Electron Energy in GeV Shinwoo Nam (Ewha)

40. Summary • High-quality Silicon pixel sensors were successfully developed and produced. - the yield close to 90% (better than initial expectation) • excellent quality, typically Id <=10nA/cm2 • Si-W Test Module was built and exposed to the high-energy beams - Obtained typical performance as an EM calorimeter in the detector responses to the different beam energy and particle type. • Preliminary result of electron energy resolution : 28%/√E, • MC result : 18%/√E for perfect readout 21%/√E taking into account of noisy and bad channels - Under study for the effect of gain calibration, beam spread, and cross-talks in readout electronics • Further tests of silicon sensors with more practical integration condition is in preparation. Shinwoo Nam (Ewha)

41. Summary • Lots of progress made on Calo. R & D • Of particular, MPC R & D really much progressed • First Extruded Scintillator produced • SiCal analysis is going on and understood quite well • R & D will go on to see more progress • Looking forward to seeing you at Snowmass