m.apollonioCM18, RAL, 14/6/20071 MICE beam diffuser M. Apollonio, J. Cobb, P. Lau, W. Lau, J. Tacon, H. Witte, S. Yang - Univ. Oxford circa 87 BC

m.apollonioCM18, RAL, 14/6/20072 outline  A bit of history …  Choice of radius  Choice of thickness  Mechanics  Control  Conclusion/Plans

m.apollonioCM18, RAL, 14/6/ Z=-6010 mm for the downstream face of the diffuser. (CR, CM14 Osaka ) 1. radial size R as big as possible 2. thickness limited number of discs to fulfil MICE configurations 3. mechanics & control design still evolving a) new carousel wheel b) motors c) ideas for control (logic)

m.apollonioCM18, RAL, 14/6/20074 radial size

m.apollonioCM18, RAL, 14/6/20075 LEADING IDEA trying to exploit all the radial space (15 cm) within the envelope being compatible with mechanical constraints

m.apollonioCM18, RAL, 14/6/ mm 15.5cm Emi inflation in single layer lead diffuser: 2.8  6.1 mm rad 7mm emi(after diff)=6 mm rad Muons selected on the overall channel ideal disc

m.apollonioCM18, RAL, 14/6/ mm 5cm 15.5cm Emi inflation with a single layer of lead (small radius): 2.8  5.3 mm rad 7mm

m.apollonioCM18, RAL, 14/6/ mm 5cm 15.5cm Emi inflation in a staggered lead diffuser: 2.8  6.1 mm rad 7mm a more realistic diffuser fixed annulus movable disc + support

m.apollonioCM18, RAL, 14/6/20079 emi(R)/emi(R=30 cm) R_diffEmittance bias as a function of R_diff (partial inflation) Pz=209 MeV/c, emi=10mm rad, B=4 T Pz=148 MeV/c, emi=10mm rad, B=2.9 T Pz=267 MeV/c, emi=10mm rad, B=4 T single disc staggered discs

m.apollonioCM18, RAL, 14/6/ mm Proposal to accommodate many configurations  STAGGERED/TAPERED with a fixed external annulus …just a sketch (see Peter/Joseph/Stephanie drawings) 24 to 27 cm 30 cm trackerdiffuser envelope Supports (outer can/disc support): Al Pb diffuser disc and outer annulus 1.5 to 15.5 mm

m.apollonioCM18, RAL, 14/6/ thickness choice

m.apollonioCM18, RAL, 14/6/ = 1.4 mm rad un-normalized How many configurations we need? want? …

m.apollonioCM18, RAL, 14/6/ … maybe 5 discs are enough (at least to begin with) Thinner disc: Pb  Steel? MICE note in preparation

m.apollonioCM18, RAL, 14/6/ mechanics

m.apollonioCM18, RAL, 14/6/  automatic device with 3 main movements & accurate positioning  Carousel (revolving)  Discs (+/- 15 deg)  Catcher (linear motion through a threaded cylinder)

m.apollonioCM18, RAL, 14/6/ New design hub air motors empty station diffuser disc on holder encoder

m.apollonioCM18, RAL, 14/6/ Disc 2 Disc 1 Dummy Disc Disc 5 Disc 3 Disc 5 Motor A Motor B Motor C P. Lau

m.apollonioCM18, RAL, 14/6/ To verify whether the lead is in the bayonet gear or not To identify which lead is at The center of the beam Motor A P. Lau

m.apollonioCM18, RAL, 14/6/ Motor B to drive to turn the disc holder 15° clockwise & anti-clockwise Encoder Encoder Reader Bayonet Gear; Turn 15° to clockwise to unlock and anti- Clockwise to lock P. Lau

m.apollonioCM18, RAL, 14/6/ This gear is to drive the diffuser catcher forward and backward Motor C P. Lau

m.apollonioCM18, RAL, 14/6/ optical sensors to check disc position (4) + disc presence (1) MICE axis

m.apollonioCM18, RAL, 14/6/ bit ~Gray code When this bit is 1 we sense the disc

m.apollonioCM18, RAL, 14/6/  -switches (check if disc at bottom of TH) 1 optical sensor (check if disc at top of TH)  S1  S2 OS catcher Pb disc + frame Pb external annulus S. Yang

m.apollonioCM18, RAL, 14/6/ OS: carousel and disc OS: disc holder encoder

m.apollonioCM18, RAL, 14/6/ T 0.32 T 0.53 T B>= 4T B (T) Z (m) R (m) motors in the magnetic field  can they work ?

m.apollonioCM18, RAL, 14/6/ Air Motors Must be non- magnetic Acetal Body, SS shaft, Ceramic bearing. The company does it is Dynatork –10 to 12 weeks deliver time –The cost is around £1,000 excludes VAT for 3 off Working pressure – 100 PSI The maximum torque is 2.8 Nm The speed is 200 rpm No speed control No positioning control What problem we will tackle due to above parameter? 1.How to stop it? 2.Any accuracy concerns?

m.apollonioCM18, RAL, 14/6/ For the Carousel The total mass is about 70 kg The moment of inertia is about 5.1 kg m² To stop the carousel:- 1.To reduce the speed by introducing the gear box A with gear ratio 200:1, driving teeth ratio 3:1, total reduction is 600:1 2.By use of the binary sensor to read the position of carousel. 3.By using the spring ball and dimple to guide the stop position of the carousel. 4.Use the lock pin to hold the carousel in place before the next motion

m.apollonioCM18, RAL, 14/6/ For the 15° disc holder Drive by the air motor B; 1.To reduce the speed by introducing the gear box B with gear ratio 51:1, teeth driving ratio 7.77 :1, total reduction is 400:1 2.By use of the Heidenhein 4000 series encoder to ensure the very high accuracy of positioning.

m.apollonioCM18, RAL, 14/6/ For the diffuser plate transportation To locate the lead disc; 1.To reduce the speed by introducing the gear box C with gear ratio 3:1 and the teeth driving ratio of 2.7:1, total reduction is 8.1:1 2.Use RS- micro switch to detect the position of the lead disc at the bottom position. 3.Use RS reflective photo sensor to detect the top position of the lead disc.

m.apollonioCM18, RAL, 14/6/ Epicyclic Gear Arrangement: For 1 rotation of shaft L shaft S rotates: ( 1 + NA / NS ) Gear Ratio: (1+42/14) = 4:1 with shaft S as the input. InputOutput J. Tacon

m.apollonioCM18, RAL, 14/6/ logic & control

m.apollonioCM18, RAL, 14/6/ Start: go to Nf (  S1&&  S2) off? OS on? Which disc is in? Nd Move C to position N d Nd = 0 Extract disc Move catcher to bottom Move C to position Nf Insert disc Go to dummy station STOP Move Catcher to top STOP !!! ERROR align disc holder: motor ACW (-15 deg abs) align disc holder: motor CW (+15 deg abs) Move catcher to bottom Go to dummy station Command: set disc-f for run mode NB: need to know WHICH disc is in ! Diffuser Control Flow Chart: main cycle

m.apollonioCM18, RAL, 14/6/ Diffuser Control Flow Chart: check discs inserted at the end of this cycle I should have a 5-element vector like (1,1,1,0,1) telling which station is empty. If the number of empty stations (Ne) is greater than 1 an error is produced which stops the system Sense disc START GO TO position Ns Record station (Ns: 0,1) If 0  Ne=Ne+1, Nd=Ns If 1  NT=NT+1 Ns=1 NT=0, Ne=0 Ns>=6 Ns=Ns+1 Go to dummy station Ne<=1? STOP !!! ERROR

m.apollonioCM18, RAL, 14/6/ Diffuser Control Flow Chart: move C to position Nd Rotate CAROUSEL C.W. (till OS fires Nd) Turn ON motor (+A) STOP START OS firing on mark Nd? 1.STOP motor (A) 2.Push BR-PIN 3.Start timer 1.release BR-PIN t>3 s? OS reads Nd? STOP !!! ERROR

m.apollonioCM18, RAL, 14/6/ Diffuser Control Flow Chart: Extract Disc STOP START t > 5 s? 1.Pull linear stage OUT = turn motor on (-C) 2.Activate TIMER (check extraction time t)  S1 &&  S2) off? STOP !!! ERROR OS on? Turn C-motor off NB motor be stiff/stable Unlock catcher: turn motor ACW -15deg Encoder reads -30? Update DISC position in memory CTRL program Y N Align disc holder(s) turn motor CW +15deg abs

m.apollonioCM18, RAL, 14/6/ Diffuser Control Flow Chart: Insert Disc STOP START Encoder +30? Unlock circular plate: Turn motor CW +15 deg STOP !!! ERROR Turn B-motor off (B) Turn on (+C): Push linear stage Activate timer t > 5 s? OS off? Register DISC POSITION in memory for the CTRL PROGRAM  S1 ||  S2) on? Turn C-motor off Y N

m.apollonioCM18, RAL, 14/6/ Integration

m.apollonioCM18, RAL, 14/6/ S. Yang Frascati 2005 CM

m.apollonioCM18, RAL, 14/6/ Quench Studies

m.apollonioCM18, RAL, 14/6/ Forces - Structure

m.apollonioCM18, RAL, 14/6/ Stresses

m.apollonioCM18, RAL, 14/6/ Conclusions

m.apollonioCM18, RAL, 14/6/ “diffuser”: not just a piece of lead across the beam a staggered/tapered disc+annulus with a clockwork insertion system thicknesses nearly finalized (assumption on Pz and initial emi.) evolved to a rather complicated mechanism possible flaws/show stoppers need to be found/cured periodical (weekly) meetings (PL, SY, JT, HW, JC, MA, WL) external review (?) control based on optical sensors and mechanical  -switches design nearly finished (some issues on space) (PL, SY, JT) gear boxes custom made (JT) control logic in progress (MA) quench induced forces (HW) next step: integration with tracker (SY, WL, …)