| PHENIX High pt Upgrades -- Overview -- |
| Yasuo MIAKE for High pt Upgrade Team | |
| http://utkhii.px.tsukuba.ac.jp/~highpt/ |
| Proposal |
| To enhance the PID capability of PHENIX, we like to install Aerogel counters (160 cells) at W1 Sector on the West Arm. | |
| Together with the Aerogel, TOF and RICH, we can extend the PID beyond 5 GeV/c. |
| Proposed Extention of PID with Aerogel |
| Physics Motivations |
| From basic strategy, it is natural extension for PHENIX to extend its PID in higher pt region. | |||
| Strong motivation given; | |||
| Jet Quenching!? | |||
| Large suppression of pions at high pt , while protons show binary scaling!? | |||
| Meson/baryon puzzle? | |||
| Need to extend PID > 5 GeV/c | |||
| Transition Region to Jet Fragmentation |
| Hadronic Flow vs Flow at Quark Level? | |
| Seems to important to measure the transition region to Jet fragmentation. | |
| PID (pion, kaon, proton) beyond 5 GeV/c is the goal. |
| What STAR is doing |
| We like to go beyond 6 GeV/c with pion, kaon and proton. |
| Aerogel Panel on the West |
| 4.5 m from the vertex to the center of Aerogel. | |
| Coverage ; full z, 15 degree in phi. | |
| Space available for new TOF. |
| Design of Aerogel Panel |
| Direction of every other cell is reversed, so that | ||
| Aerogel locates at the same distance from the vertex, | ||
| No dead space in between. | ||
| Cell Design |
| PMT assembly (prototype) |
| Silica Aerogel |
| Best index with RICH(CO2) is n< 1.007, too small. | ||
| SP-12M (Matsushita) | ||
| Silica aerogel with Lowest refractive index commercially available. | ||
| Hydrophobic | ||
| Long term stability proved by KEK-Belle. | ||
| PMT |
| 3” PMT for photon counting | |
| Gain of > 10^6 at 1500 V w. 1-1-1-1- voltage divider | |
| One p.e. resolution |
| Bleeder |
| Hand made bleeder | ||
| Thinner material | ||
| Less space | ||
| Less power (330 mW@1500V) than Hamamatsu standard | ||
| Tested upto 3.2 kV for 6 hours | ||
| Magnetic Field on the West |
| Magnetic field of the location measured as < 8 G. | ||
| Goal set as 16 Gauss ! | ||
| Thickness & Size of the mu-metal shield has been optimized using Helmholz Coil. | ||
| Mu-metal Shield |
| Magnetic shield of 0.2 mm thick breaks down at around 10 G. | ||
| Loss of Gain & | ||
| Loss of Q.E. | ||
| Magnetic shield of 0.5 mm survive till 20 G. | ||
| Final Prototype Test at KEK |
| June, 2003 at KEK | ||
| SP-12M | ||
| R6233-01HA w. Bleeder | ||
| Pre-Amp w. cables | ||
| Dubna Box | ||
| Expected performance | ||
| Normal ~ 14 p.e. | ||
| Reverse ~ 12 p.e. | ||
| Observed Clean Signal |
| Very clean separation | ||
| Amount of photons other than Aerogel Chrenkov is small! | ||
| Observed Uniform Response |
| Uniform response, thanks to Integration Volume | ||
| Important to separate in the momentum region of slow rise | ||
| ~10% diff. between normal/reverse, due to diffusive nature of aerogel | ||
| Uniformity Confirmed at Dubna |
| Independent Beam Test at Dubna in June 2003. | |
| Tested at Dubna with final prototype, but with SP-15. | |
| Independent setup & calibrations |
| Cherenkov Light from PMT window |
| Cherenkov from PMT window; | ||
| Huge pulse height | ||
| Faster Timing (> 5 ns) | ||
| Background Rejection |
| Photons from PMT windows can be identified/recognized by itself, | |||
| Faster Timing (>5 ns) | |||
| Consistent with optical simulation | |||
| ADC-ADC correlation | |||
| Other sources of photons are carefully surveyed and <1p.e. | |||
| TDC-TDC difference can be used for track association. | |||
| Simulation for PID Performance |
| Assumptions; | |||
| HIJING Au+Au 200 GeV | |||
| Aerogel; | |||
| n =1.011 | |||
| Saturated at 14 p.e. w. poissson distr. | |||
| Occupancy 10% | |||
| RICH ; | |||
| n =1.0044 (CO2) | |||
| Saturated at 10 p.e. w. poissson distr. | |||
| Occupancy 3.4 % (NIM) | |||
| Expected Proton Identification |
| Require No-Aerogel & No-RICH |
| Expected Kaon Identification |
| Require Aerogel & No-RICH (Need TOF for < 5 GeV/c) |
| PISA Activity |
| All the known material put into PISA. | |
| Occupancy ~ 8 % |
| Radiation Length by PISA |
| <Lrad> ~20 % | ||
| Similar to TOF | ||
| Aerogel/PMT Preparation at Tsukuba |
| Box Production/Inspection at Dubna |
| Dubna Contributions |
| Dubna contributions have been very important from R&D’s to productions. |
| Status of Safety Issues |
| Known issues; PMT-holder, HV protector |
| Electronics & Trigger Issues |
| Installation Procedure |
| Each half panel, 80 cells, is installed through the gap from North and South. |