july 10p. z. yang sic 1 status of pwo crystal growth at sic peizhi yang on behalf of pwo crystal...
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July 10 P. Z. Yang SIC 1
Status of PWO crystal growth at SIC
Peizhi YANG
on Behalf of PWO Crystal Growth Group
SIC, 10th July 2004
July 10 P. 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 furnacesB. Buy Pt C. Buy crystal processing machinery
Total investment Processing cost
July 10 P. 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 10 P. Z. Yang SIC 4
Bridgman method
Crucible configuration of Bridgman Method for PWO growth
July 10 P. Z. Yang SIC 5
Modified Bridgman 28 crystal growth furnace
July 10 P. 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 10 P. Z. Yang SIC 7
Growth condition and parameters
– Vertical Bridgman Furnace with 28 crucibles
– DWJ-100 temperature control system
– Temperature precision is 1oC
– Growth temperature 1173oC (melting point 1123oC +50oC)
– Two times re-crystallization
– Doping with Y2O3(150ppm)
– Lowering rate 0.8~1.0mm/hr
– Crystal size up to 250mm, 32mm*32mm section
July 10 P. 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 10 P. Z. Yang SIC 9
Next plan :(2) Purchase PtUnit cost: 30K$/kg
Presently available: 50kg
3750 EE– Total Pt needed: 100kg – Newly wanted: 50kg, 50kg×30K$/kg=1.5M$
3750 EE+1700 EB– Total Pt needed: 135kg – Newly wanted: 85kg, 85kg×30K$/kg=2.55M$
3750 EE+3400 EB– Total Pt needed: 200kg – Newly wanted: 150kg, 150kg×30K$/kg=4.5M$
July 10 P. 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 10 P. Z. Yang SIC 11
Total investments
3450EE 3450EE+1700EB 3450EE+3400EB
Furnaces(K$) 225 360 580
Pt(K$) 1500 2550 4500Processing
machinery(K$) 350 350 350
Total(M$) 2.075 3.26 5.43
early contribution of SIC:
50kg Pt(1.5M$) + 5 sets of furnace(0.225M$) = 1.725M$
July 10 P. 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 10 P. 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.