Forward Shashlyk Calorimeter: Status and Plans

1. FSCStatus and Plans Pavel Semenov IHEP, Protvino on behalf of the IHEP PANDA group PANDA Russia workshop, ITEP 27 April 2010

2. Outline • FSC position and function • FSC mechanical structure • FSC photodetectors and monitoring system • FSC prototypes studies results review • FSC software activity • Summary Pavel Semenov, PANDA Russia Workshop, ITEP

3. EMC at PANDA detector Forward Shashlyk Calorimeter Pavel Semenov, PANDA Russia Workshop, ITEP

4. Fast MC (photons energy distribution) All photons energy over photons at the Shashlyk aperture (color curves) from interactions with 5 and 15 GeV/c beam Pavel Semenov, PANDA Russia Workshop, ITEP

5. Charmonium study, 6.27 GeV/c beam Energy of photons from charmonium decays going to FSC is relatively small, registration threshold should be similar to EMC Pavel Semenov, PANDA Russia Workshop, ITEP

6. Shashlyk cell structure • 380 layers of 0.3-mm lead and 1.5-mm scintillator, total length 680 mm • Transverse size 55x55 mm2 • Light collection: 36 fibers BCF-91A (1.0mm) • PMT as a photodetector • LED for each supermodule as a light monitoring system + one optical fiber for each PMT to monitor gain? Pavel Semenov, PANDA Russia Workshop, ITEP

7. FSC mechanical support Frame consists of two non-symmetrical parts Maintenance without beam pipe removal Pavel Semenov, PANDA Russia Workshop, ITEP

8. Detector maintenance position FEE crates can be placed on the support frame sides All the cables on the back side, heat load? Pavel Semenov, PANDA Russia Workshop, ITEP

9. Detector assembly procedure Removable beam for a time of half-part detector assembly Pavel Semenov, PANDA Russia Workshop, ITEP

10. CW control and monitoring system • CW multipliers for Hamamtsu R5800 and R7899 were tested during prototype studies. Multiplier require only few wires (SPI lines, +/- 6V and 100V power). An amplifier or a shaper can be easily added. • CW control unit (up to 64 channels) was developed for the shashlyk prototype testbeam (based on microcontroller to program each channel HV by SPI protocol, monitoring of voltages and currents by on-chip ADC, remote control… ) • LED driver to inject light into each of the 16 supermodules showed good long term stability during test beam run. To monitor PMT gain we will probably use one additional optical fiber for each PMT and one powerful LED for a part of the calorimeter. • Combination of the two systems into one block provides a smart node to test photodetectors and shashlyk part of the DAQ. Pavel Semenov, PANDA Russia Workshop, ITEP

11. Shashlyk supermodule structure One additional fiber for each PMT to monitor gain can be used A hole for the monitoring system LED Pavel Semenov, PANDA Russia Workshop, ITEP

12. Photodetector selection • The goal was to test several PMT’s types (noise, dyn.range, rate effect, signal width, quantum eff.) • Now we are in the process of testing samples from Hamamatsu and ElectronTubes (Photonis “temporarily” doesn’t produce PMTs) • R1925 looks attractive (like R7899 but more compact, only 43 mm and green enhanced) • ETL 9085B – compact, good stability, but expensive Pavel Semenov, PANDA Russia Workshop, ITEP

13. Cosmic muon test stand measurements • To study PMT spectrum and WLS fiber spectrum match with cosmic muons • Horizontal and vertical position of the Shashlyk module (MIP ~1:10) • ETL9085 23.1 • R7899 34.5 • R1925 25.0 Cosmic muons spectrum (horizontal position of the Shashlyk module) Pavel Semenov, PANDA Russia Workshop, ITEP

14. M14 DC2 DC3 DC4 ECAL Testbeam setup • Spectrometer consisted of 4 drift chamber stations and a magnet to measure beam particle momentum precisely • Calorimeter prototype • Al target at 1.5m and 3 m before the prototype DC1 Target Beam S3 S2 S1 St SA Pavel Semenov, PANDA Russia Workshop, ITEP

15. Prototype resolution measurements (55х55 mm2) Position resolution For 55х55 cell at 19 GeV: Cell center 3 mm (6 mmfor big cell), Cell edge 1.5 mm For both cell sizes σE /E = 5.6/E  2.4/√E  1.3 [%] σE /E = 3.5/E  2.8/√E  1.3 [%](big cell) Pavel Semenov, PANDA Russia Workshop, ITEP

16. Energy deposition non-uniformity Fiber positions Non-uniformities in the order of 1% at the fiber positions because of Cherenkov light in the fiber Pavel Semenov, PANDA Russia Workshop, ITEP

17. π0reconstruction results for 1.5 m Shower profile fit ( to resolve overlapping showers), Charged hadrons removed (drift chamber), Rough calorimeter calibration π0 1-2 GeV, σm 12.5 MeV Pavel Semenov, PANDA Russia Workshop, ITEP

18. Summary and plans • Mechanical design of the FSC support frame is almost ready. Plans to calculate mechanical stress distribution and temperature fields to design appropriate heat removal system • Photodetector selection with cosmic muons test stand is under way, Hamamatsu R7899 is a most probable candidate. PMT HV bases Cocroft-Wolton type were used for testbeam measurements. • Shashlyk prototypes testbeam results show good performance with charge integrating ADC. Plans to study prototype with sampling ADC readout during December 2010 testbeam run. Go to MAMI in 2011 to test low energy detection threshold? • IHEP irradiation facility to study shashlyk radiation hardness is almost ready. • FCS code in the PandaRoot frame will be ready soon. Plans to use it for simulation required for FSC TDR. Pavel Semenov, PANDA Russia Workshop, ITEP

19. Backup slides Pavel Semenov, PANDA Russia Workshop, ITEP

20. Shashlyk photodetectors position Pavel Semenov, PANDA Russia Workshop, ITEP

21. Time between energy depositions (one cell) Near pipe Detector vertical edge Pavel Semenov, PANDA Russia Workshop, ITEP

22. Prototype testbeam setup Pavel Semenov, PANDA Russia Workshop, ITEP

23. 3 meter gamma-gamma mass spectrum Neutral pions energy range 3-10 GeV FWHM 40 MeV Pavel Semenov, PANDA Russia Workshop, ITEP

24. Registered neutral pions energies at 3 m target position Pavel Semenov, PANDA Russia Workshop, ITEP

25. 1.5 m target position Pavel Semenov, PANDA Russia Workshop, ITEP