July 10P. Z. Yang SIC 1 Status of PWO crystal growth at SIC Peizhi YANG on Behalf of PWO Crystal Growth Group SIC, 10 th July 2004

July 10P. Z. Yang SIC 2 Outline  Current status of PWO crystal growth at SIC  Advantages of modified multi-crucible Bridgman method  Current status of PWO crystal growth  Next plan for collaboration with CMS-ECAL  Build-up the infrastructure A.Build the furnaces B.Buy Pt C.Buy crystal processing machinery  Total investment  Processing cost

July 10P. Z. Yang SIC 3 Advantages of Bridgman growth method Compared with other crystal growth method, Bridgman has the following advantages: 1)simple in operation without complicated control system; 2)possibility of using multi-crucible for growth of crystals with different sizes; 3)ability to get uniform crystals owing to low temperature gradient; 4)suitable for growing crystals with components having higher vapor pressures because the melts are sealed in crucibles and evaporation can be avoided; 5)the crystals with desired shape can be grown and the utilization ratio of materials is high. Bridgman technique is very suitable for PWO crystal growth

July 10P. Z. Yang SIC 4 Bridgman method Crucible configuration of Bridgman Method for PWO growth

July 10P. Z. Yang SIC 5 Modified Bridgman 28 crystal growth furnace

July 10P. Z. Yang SIC 6 Current furnaces and crystal growth rate  Currently there are 5 sets of furnaces in operation: –3 sets of them for crystal growth –2 sets of them for first crystallization and growth of seeds  3 sets of furnaces can produce 90~100 crystal ingots per month. The growth time is about 20 days. The growth yield is about 80%.

July 10P. Z. Yang SIC 7 Growth condition and parameters –Vertical Bridgman Furnace with 28 crucibles –DWJ-100 temperature control system –Temperature precision is  1 o C –Growth temperature 1173 o C (melting point 1123 o C +50 o C) –Two times re-crystallization –Doping with Y 2 O 3 (150ppm) –Lowering rate 0.8~1.0mm/hr –Crystal size up to 250mm, 32mm*32mm section

July 10P. Z. Yang SIC 8 Next plan :(1) Build up furnaces Unit cost: 45K$/set 5 sets ready  3750 EE –Total furnaces needed: 10 sets –5 sets to be built up: 5×45K=225K$  3750 EE+1700 EB –Total furnaces needed: 13 sets –8 sets to be built up : 8×45K=360K$  3750 EE+3400 EB –Total furnaces needed: 18 sets –13 sets to be built up: 13×45K=585K$

July 10P. Z. Yang SIC 9 Next plan :(2) Purchase Pt Unit cost: 30K$/kg Presently available: 50kg Ù 3750 EE –Total Pt needed: 100kg –Newly wanted: 50kg, 50kg×30K$/kg=1.5M$ Ù 3750 EE+1700 EB –Total Pt needed: 135kg –Newly wanted: 85kg, 85kg×30K$/kg=2.55M$ Ù 3750 EE+3400 EB –Total Pt needed: 200kg –Newly wanted: 150kg, 150kg×30K$/kg=4.5M$

July 10P. Z. Yang SIC 10 Investment :(3) Crystal processing machinery Total investment: 350K$ Crystal processing investments mainly include: (1) cutting machines; (2) lapping machines; (3) polishing machines, et al.

July 10P. Z. Yang SIC 11 Total investments 3450EE3450EE+1700EB3450EE+3400EB Furnaces(K$) Pt(K$) Processing machinery(K$) 350 Total(M$) early contribution of SIC: 50kg Pt(1.5M$) + 5 sets of furnace(0.225M$) = 1.725M$

July 10P. Z. Yang SIC 12 (4) Processing cost Processing cost: 2.4$/cc Processing cost include: (1) raw materials and other consumables; (2) Pt crucible processing cost and loss; (3) crystal processing; (4) electricity consumption; (5) manpower, et al.

July 10P. Z. Yang SIC 13 Summary ( Modified Bridgman technique is very suitable for growing PWO crystals with high quality. ( Optimal growth parameters for mass produced PWO crystals were established. Growth yield is about 80% and will be stepwise increased in the coming 6 months. Meanwhile, the crystal quality will also be improved. ( We estimated the total investment for meeting CMS-ECAL demands. Pt cost is the large one.