PVDIS Toroid Detector outline and costs Paul E

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PV-DIS Toroid Detector: outline and costs Paul E. Reimer 12 Ge. V PV-DIS detector

PV-DIS Toroid Detector: outline and costs Paul E. Reimer 12 Ge. V PV-DIS detector meeting 12 -13 August 1. Introduction to Toroid Concept (presenting work done by Eugene Chudakov) 1. 2. See Eugene’s talk and http: //www. jlab. org/~gen/jlab 12 gev/tor_sim/ 2. Detector Package (my rough guess) 3. Cost Estimate (my even rougher guess)

Toroid concept n Tracking detectors screened from target. See Eugene’s page at http: //www.

Toroid concept n Tracking detectors screened from target. See Eugene’s page at http: //www. jlab. org/~gen/jlab 12 gev/tor_sim/ n With long targets, the momentum can not be measured. n Solution: Use two toroidal magnets: – TOR 1: a strong magnet focusing the DIS electrons parallel to the beam; – TOR 2: a magnet similar dimensions as TOR 1, but weaker, providing the momentum measurement. n Both TOR 1 and TOR 2 bend electrons toward the beam. n Detectors are located between TOR 1 and TOR 2 and downstream of TOR 2. n Drawbacks – The need to build at least 1 new magnet—G 0 magnet may work for 2 nd magnet – Limited to particles with one charge (a solenoid without baffles can take both) – Potentially larger error on the scattering angle. Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 2

Toroidal Field High current density n Standard 1/R field will not focus particles of

Toroidal Field High current density n Standard 1/R field will not focus particles of interest n Constant field (e. g. dipole) provides better focusing Low current n The average azimuthal (along φ) field at a radius R is density B = 0 I/(2 R) = 2£ 10 -7 I/R where R is the current flowing through the circle of radius R. The units are T, m, A. Low n TOR 1 needs a uniform field of 2. 5 T at R=0. 4 -1. 5 m. current – Requires I=5 MA at R=0. 4 m and I=18. 75 MA at density R=1. 5 m, changing linearly with R. n Wind coils with 1/R current density – Possibly use iron to additionally shape field n For comparison, the G 0 magnet uses a current of I=5. 76 MA at R≅0. 5 -1. 5 m. n Again, see Eugene’s work for more details Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector High current density 12 -13 August 2008 3

Toroidal Field Parameter Number of coils TOR 1 G 0 8 Ideal Calculation 1

Toroidal Field Parameter Number of coils TOR 1 G 0 8 Ideal Calculation 1 Calculation 2 8 8 12 Full current along Z at R=0. 4 m 5. 76 MA 5. 00 MA Full current along Z at R=1. 5 m 5. 76 MA 18. 75 MA Superconductor cable 20 strands 36 strands Cross section of the copper support cable 20× 5 mm² same 5000 A/cm² 10000 A/cm² 6666 A/cm² 4 2 4 4 8× 18 cm² 4× 15. 6 cm² 8× 8 cm² Full coil thickness in φ 15 cm 11 cm 15 cm Bφ at ≅0. 4 m 2. 88 T 2. 50 T 2. 30 T Bφ at 1. 5 m 0. 77 T 2. 50 T 1. 43 T 1. 64 T - - 7. 6 T 5. 5 T Full current density d. I/d. R at R=0. 4 -1. 5 m none 125 k. A/cm ? Cables per unit length in R, at R=0. 4 -1. 5 m none 0. 78 per cm 1. 25 per cm 8× 18 cm² 4× 60 cm² 8× 30 cm² - - 196 7. 6 - 52 45 Current density Cable layers per coil Coil cross section, at R=0. 4 m Bmax Coil cross section, at Rmax≅1. 5 m Full number of turs per coil Stored energy, MJ Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 4

n Close to the coils, at the lower radii of R<100 cm, the field

n Close to the coils, at the lower radii of R<100 cm, the field has a radial component. This component cases a "defocusing" of the trajectories at smaller scattering angles, moving them toward the coil. At larger angles some focusing occurs, with the trajectories moved to the center of the sector. The effect is illustrated on the next picture for the map (2), made with no absorption in the ideal TOR 2 coils. The effect leads to a loss of acceptance, since some of the "defocused" electrons hit the coil of TOR 2. n The trajectories for DIS at φ=12°, 22°<θ<35°, 0. 65; <x<0. 85. The field map (1) was Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 5

Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008

Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 6

Kinematic Resolution Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13

Kinematic Resolution Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 7

Momentum measurement n Need trajectory and a point: Paul E. Reimer 12 Ge. V

Momentum measurement n Need trajectory and a point: Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 8

Detector Package n Minimum needed for momentum measurement: – Trajectory on one side of

Detector Package n Minimum needed for momentum measurement: – Trajectory on one side of the magnet and a point on the other – Select up stream for trajectory (smaller chambers) downstream for point n Both preshower and shower detectors n 2 x-y hodoscope arrays n Cherenkov counter Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 9

Shower n Pb-Glass calorimeter n 10 x 40 cm 3 blocks – ≈$0. 764/cm

Shower n Pb-Glass calorimeter n 10 x 40 cm 3 blocks – ≈$0. 764/cm 3 – Volume area ≈6, 100 cm 2 x 40 cm deep ≈224 k cm 3 – Cost per wedge ≈$187 k n Readout – 66 channels – PMT, base, shield ≈$400/channel – ADC, Delay, Splitter, discriminator ≈$150/channel – Cost per wedge ≈$33. 6 k n Total Cost – Cost per wedge ≈$223 k – Total ≈$1. 8 M Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 10

Pre. Shower n Pb-Glass calorimeter n 10 x(35 -60) cm 3 blocks (shorter off

Pre. Shower n Pb-Glass calorimeter n 10 x(35 -60) cm 3 blocks (shorter off axis) n Cost estimate from Prim. Ex Pb-Glass from ITEP – ≈$0. 764/cm 3 – Volume area ≈6, 100 cm 2 x 10 cm deep ≈61 k cm 3 – Cost per wedge ≈$46. 7 k n Readout – 16 channels – PMT, base, shield ≈$400/channel – ADC, Delay, Splitter, discriminator ≈$150/channel – Cost per wedge ≈$8. 8 k n Preshower – Cost per wedge ≈$55. 5 k – Total ≈$444 k Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 11

Drift chambers or MWPC n Issue is rate capability vs cost – MWPC can

Drift chambers or MWPC n Issue is rate capability vs cost – MWPC can take 10×rate (occupancy & faster gas) – MWPC cost more (Channels and recirc. gas syst. ) MWPC Drift Chamber n Each station has y, y 0 u, u 0 and v, v 0 layers Station 1 or 2 3 n Stations 1 and 2: Chamber Plane pair $38 k $30 k (y, y 0) 100 cm < R < 150 cm y, y 0, u, $114 k $90 k n Station 3 0 u, 50 cm < R < 150 cm v, v 0 Readout cost/channel Based on E 906/Drell-Yan Pre. Amp Readout $12. 50 Custom FPGA- $27. 50 based readout Total/wedge Total/channel Gas system $40. 00 8 wedges Total channels/ plane 250 50 100 Plane $10 k $2 k $4 k Chamber $60 k $12 k $24 k $174 k $234 k $102 k $120 k $200 k $1. 6 M $2. 0 M $5. 2 M Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector $50 k $866 k $961 k $2. 7 M 12 -13 August 2008 12

Hodoscopes n 10 cm wide x and y planes to match Pb-glass – ≈$1,

Hodoscopes n 10 cm wide x and y planes to match Pb-glass – ≈$1, 300 for scintillator, diamond milled for each layer (x or y) – ≈$700 Light guide material for each layer • Based on Spring ’ 07 quote for E 906/Drell-Yan, but Scintillator is made from Oil—expect factor of 1. 5 inflation – Cost per wedge ≈($1, 300+$700) x 2 layers (x, y) x 2 stations x 1. 5 inflation ≈$12 k/wedge n Readout – 30 channels/wedge/station x 2 stations = 60 channels/wedge – PMT, base, shield ≈$400/channel – ADC, Delay, Splitter, discriminator ≈$150/channel – Cost per wedge ≈$27 k n Total Cost – Cost per wedge ≈$39 k – Total ≈$312 k Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 13

Cherenkov Counter n Based on CLAS High Threshold Cherenkov for 12 Ge. V upgrade

Cherenkov Counter n Based on CLAS High Threshold Cherenkov for 12 Ge. V upgrade – ≈$750 k for 6 fold symmetry or $125 k/wedge – Less contingency, etc (put these back in later) $125 k/1. 4=$90 k – Smaller individual volumes and less complication $90 k/2 = $45 k/wedge n Total Cost $360 k for 8 wedges Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 14

Bottom line on cost without magnet n This could be too expensive Where can

Bottom line on cost without magnet n This could be too expensive Where can there be savings: n Pb-Glass – Fewer radiation lengths? – In kind contribution from foreign source? n Reduce tracking resolution – x, x 0, y, y 0 n 1140 PMT channels @$550 each – Do we need this granularity? – Can it be obtained more cheaply? n 6 wedges rather than 8? – Fewer channels – Less uniform field n Are all detector elements necessary? Item Cost MWPC Shower counter Pb-Glass $1, 800 k Pre. Shower counter Pb-Glass Tracking Drift $444 k $5, 200 k $2, 700 k Hodoscopes $312 k Threshold Cerenkov $360 k Total $8, 116 k $5, 616 k Contingency factor × 1. 3 $10, 551 k $7, 300 k Inflation factor × (1. 03)2 = 1. 06 $11, 200 k $7, 740 k Caveat: This is a “straw person” cost estimate—meant to be shot down n No attempt to reuse available equipment: – Tracking electronics, PMT, ADC readout, Scintillator? Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 15

Conclusion n Toroid magnet concept can make appropriate measurements for PVDIS studies—see Eugene’s talk

Conclusion n Toroid magnet concept can make appropriate measurements for PVDIS studies—see Eugene’s talk and http: //www. jlab. org/~gen/jlab 12 gev/tor_sim/ n Potential for other physics needs to be examined – Spectrometer can only focus one charge of particle at a time! n Requires double toroid with nearly constant B field in each toroid – Done with multiple radius windings n No complicated spiral baffles – No scattering from baffles n Drawbacks: – Toroid fabrication possibly costly – Detector package possibly costly Paul E. Reimer 12 Ge. V PV-DIS Large Acceptance Detector 12 -13 August 2008 16