sPHENIX Silicon Tracker 2015/10/20 Japan Korea PHENIX collaboration meeting Y. Akiba (RIKEN)

Reference design and requirements |  |<1 and  High efficiency & purity in central Au+Au to measure modified FF High rate (15kHz DAQ) High momentum resolution to separate Upsilon states Precision vertex measurement for heavy flavor measurements (D, B  J/Psi, b-tagged jets) Compact (Fit inside of EMCAL) J.Nagle LPR talk

Silicon tracker in pCDR

Current design in pCDR

Simulation of the current design (in pCDR) Expected momentum resolution and mass resolutions for Upsilon calculated by Tony Frawley for preliminary Conceptual Design Report  =94 MeV for Upsilon. Three upsilon states are clearly separated

Concept of Sensor (for S2) 96mmx92.16mm active area Divided into 10x12 blocks Each block is 9.60mm x 7.68mm and made of 128 strips of 8mm x 60 micron Upper 6 bocks are connected upwards. Lower 6 blocks are connected by downwards 24 FPHX chips to read- out the entire sensor

3 sensors for strip layers Each sensor is divided in cells of 9.6m(z)x7.68mm active area. Each cell consists of 128 strips of 60  m x 9.6mm S2, S1, S0 sensors are made of 12x10, 6x10, and 2x10 cells, respectively 1 ch in S2 read 6 strips and 1 ch in S1 read 3 strips to save channel counts. Channel occupancy is ~0.2% in S1 and 0.1% in S1 in central Au+Au. Bonding pads for 10 FPHXs S2 sensor Bonding pads for 10 FPHXs S1 sensor Bonding pads for 10 FPHXs

Concept of FPHX based module (S1) This is a concept of a sensor module with FPHX read-out It is made of – Sensor of (6 x 10) cell structure. Each cell has 128ch of 80um x 9.6mm strips – A “ROC” (or “HDI”) of 10 FPHX chips. They are attached at the top and the bottom of the sensor – The “HDI” is electrically equivalent to the “small HDI” of FVTX so that it can be read- out by a FVTX test bench HDI of 10 FPHX chip

S1 silicon module

S1 ladder

S1 barrel (R=30-35cm)

S0 barrel (R~8cm)

S2 (R~65 cm)

S0, S1, S2 barrels

sPHENIX silicon tracker R&D in Japan Silicon sensor R&D at RIKEN in JFY2014 Large Prototype sensor for the outer most layer – 96 mm x 92.16mm active area – 320  m thick – AC coupled – 6x128x24 mini-trips (60  m x 8mm) – 128x24 read-out channels 5 sensors manufactured at Hamamatsu and delivered to RIKEN in March 2015 For all of 5 delivered sensors – No NG channels or strip – Vfd = 50 V – Vbreakdown > 250V (>500V for two) All 5 sensors are now at BNL for testing

I-V, C-V data Vfd: 50V No NG channels Breakdown V > 250V

Silicon tracker model for 2 nd round of R&D FPHX chip for read-out. – FPHX is the read-out chip of FVTX – 128ch/chip. 3bit ADC /ch. – Low power (64mw per chip) 5 strip layers + 2 pixel S2: 1 strip layer at R~60 cm ~1% X0 (2% in ref. design) S1ab: 2 strip layer at R~34 cm ~1% X0 total (2% in ref. design) S0ab: 2 strip layer at R~ 8 cm ~1% X0 total (2.7% in ref. design) P1: pixel at R~5 cm (reconfigured VTXP) 1.3% X0 P0: pixel at R~2.5cm (reconfigured VTXP) 1.3% X0 – All strips are 60  m x 9.6mm. S0b has a small stereo angle. – Overall material is ~5.6% radiation length. – Air cooling to achieve small radiation length – Small rad. length enables smaller over-all size and to keep the required momentum resolution to separate 3 Upsilon states – S0+S1+S2: ~8m 2 of silicon and 3.2M ch

Plan and status of 2 nd round R&D in Japan Plan: – Develop prototype S1 sensor (~5cm x 10cm, 2 sensors per wafer) at Hamamatsu – Develop read-out FPC for the sensor. – Assemble them into prototype sensor module – Test and evaluate the silicon module using FVTX test bench – About half year for the full cycle of R&D – Design and protoype of the mechanical support /cooling structure – 2 nd round of sensor module prototype in the later half of the year Goal: Protype of a full ladder at the end of JFY Status: – Started design of prototype S1 sensor at Hamamatsu. I expect that the sensor prototype will be delivered in September – Started design of read-out FPC at a FPC company near Tokyo with consultation with a wire-bonding and assembly firm. I expect that FPC will be availabe by the delivery of the sensor – Starting the mechanical/cooling design (very preliminary stage)

Current conceptual design of S1 Sensor Module prototype (work-in-progress) HDI width: ~20 mm HDI length: ~40 cm including the bus part Radiation length: 0.28% (physical thickness 0.45mm) Electrically the same as the small Wedge HDI of FVTX. This allows read-out via FVTX ROC+FEM sensor HDI Hirose connector that matches to FVTX ROC

Current concept of S1 SM Supporting frame (CFC sheet) – Width: 10 mm – Thickness: 150um (0.054% rad length) This current concept is really a work-in-progress. The main point is that we need a some sort of supporting frame to make 2 HDIs + sensor as a single object ROC and sensor Supporting frame made of CFC sheet Sensor Module = sensor + ROC + frame + =

Current (very rough) concept of S1 ladder Sensor Module = sensor + ROC + frame Cooling and Support channel Made of CFC (sandwiched by two SMs from top and bottom) Cooling and support channel. 15mm x 20 mm (wall thickness=150um) Sensor module Support frame of SM Cross sectional view The concept of the ladder is least developed. No engineering at this point. According to my rough calculation, if the cooled air is flown at 10 m/sec, the temperature Increase of the air from input to the out is about 6 deg C for 70 cm long ladder. HFT uses the flow rate of 10m/sec. Obviously more serious thermal/mechanical design is needed.

R&D plan Sensor prototype: HPK – Conceptual design done. (prevous slides) – Got quote from HPK – Sole source was approved at RIKEN on 8/20. Will make a contract soon. HDI: YAMASHITA Materials – Visit the company on 6/2 for discussion (YA, Nakagawa, Mitsuka, Taketani, Nagashima) – Layout design is on going. A few meetings with the designer/engineer of Yamashita at RIKEN – Rough cost estimate Wire-bonding/Assembly: HAYASHI – Discussion at RIKEN on 6/4 – Rough cost estimate for prototyping Goal of the first round of prototype of S1 SM – both of the sensor and HDI protoype – Assembly of SM at Hayashi – Test the module using the FVTX test bench by the end of JFY

Plan and Status of the sensor prototype Plan is to make sensors with two thickness – 320 um thick4 sensors – 240 um thick 4 sensors Two types of sensors are the same except for the thickness. – 320 um sensors are made by the HPK standard process. – 240 um sensors are made by thinning of backside of 320 um sensors Expected ENC is about So the 320 um sensor is expected to have S/N~20 and the 240 um to have S/N~15. HPK will deliver 320 um sensors 3months after the contract is made. 240 um sensors will be delivered All sensors will be tested by HPK (IV/CV curves, test of all channels and strips) and only good sensors will be delivered. Status The sole source justification was approved at RIKEN on 8/20. We expect that the contract will be made at about September 1 st. – Delivery of the 320 um at about December 1 st – Delivery of the 240 um sensors in the middle of January

HPK design of S1 sensor Received from HPK (2015/06/16)

HDI HDI (FPC to read- out the sensor) design is in progress at Yamashita Co. in Tokyo Layer structure follows that of FVTX HDI The design will be finalized in this week

Time line of R and D this year This assumes FPHX chips will be available by beginning of November (FPHX placement on HDI and wire-bonding are part of SM assembly) Both type of SMs (320um sensor, 240um sensor) will be tested by the end of JFY (Mar 2016) If 240 um sensor version works well, we will chose this as the thickness of S1 layer Depending on the performance of the test results, we may consider to make even thinner sensor.

Time line of the project

Effort to get KAKENHI funding for the tracker I submitted a large KAKENHI grant proposal to JSPS last year. – JSPS is the main funding agency in Japan. Its function is similar to NSF in the US Grant Title: sPHENIX experiment: study of quark gluon plasma by using jet probes The grant asked for total of 5 oku yen (~$5M) over 5 years from JFY2015 to JFY2019. – The end date of JFY2019 is March 2020 ~ end of sPHENIX construction – In the JSPS grant system, we receive the full amount of the allocated fund. Overhead will be provided separately. The grant passed the first stage of selection and we went to a hearing on March 26. – About 20% of applicants can go to a hearing. Half of them are approved. Unfortunately, my proposal was not accepted after the hearing. I will try again this year. I will submit a similar proposal (JFY ) this week.