NUMI Primary Beam Review August 14, 2001 NUMI PRIMARY BEAM INSTRUMENTATION Multiwires, Loss Monitors, Toroids Gianni Tassotto

NUMI Primary Beam Review August 14, 2001 MULTIWIRES Phenomenon : secondary emission Measure position and profile No clearing field needed Wire : – 0.003” AuW – 48H/48V – spacing: 1 mm, 0.5 mm Material in the beam - 8x10 -5 fractional loss Dynamic range: 5x10 10 to 4x10 13 ppp Upgrading wire plane assembly

NUMI Primary Beam Review August 14, 2001 MULTIWIRE UPGRADE Alignment - Position Repeatability - <50 um. Motor Drive - move in/out in 1.1 sec. Signal feedthroughs. Ceramic boards. Kapton flex tape. Considering using carbon wires to minimize beam losses. R&D effort. Robust limit switch assembly. Est. cost of new assembly $2500/ea.

NUMI Primary Beam Review August 14, 2001 ELECTRONICS FNAL made 96 channel integrator Integration time from 5 msec sec Dynamic range: 5x x10 13 ppp Noise  0.2% of full scale Calibration feature to check channel response

NUMI Primary Beam Review August 14, 2001 LOSS MONITORS Sealed Unit (BLM): –Lab standards. –I L = Amp. –Sensitivity (pA-hr/R). –9 months to fabricate. –Cost: about $250. –Electronics dynamic range beam loss to full scale. Heliax Type (TLM): –Various lengths & dia. –Require ArCO 2. –Cost: $14/ft for 1 5/8”. –Gas: $3k initial + about $50/month. –Max cable length one monitor 430 ft. –Electronics dynamic range beam loss to full scale.

NUMI Primary Beam Review August 14, 2001 BLM DETECTOR

NUMI Primary Beam Review August 14, 2001 CALIBRATION OF BLMs A lot of information has been obtain from work done by F. Krueger, R. Ford and myself at FNAL and R. Witkover at BNL: –Sensitivity tests on new and irradiated BLMs –Plateau at various radiation levels. –In R. Witkover’s paper: “Choise of High Voltage Bias Polarities for the SNS BLM Ion Chambers”. Witkover tested various configurations for both positive and negative voltages. Found that the FNAL type (positive voltage to the center) offered the best response at high dose rates. Also, it included sensitivity tests.

NUMI Primary Beam Review August 14, 2001 LOG AMP RESPONSE Bench test using a calibrated current. Extrapolated to Rad/sec per uAmp using R. Shafer parameters. R/s=k1*10^(Volts/k2) k1= k2= R/s per uAmp =14.3

NUMI Primary Beam Review August 14, 2001 BLM SENSITIVITY TESTS See slide “Beam Sensitivity Measurements”. Sensitivity and plateau measurements were done using a Cs 137 source (E  =662 KeV) at Site 38. Typical runs were 50 R/hr which equates to a very low intensity beam.

NUMI Primary Beam Review August 14, 2001 BLM PLATEAU SERIES Bias Current (pA) for: (volts) 100 R/hr 80 R/hr60 R/hr 40 R/hr 20 R/hr

NUMI Primary Beam Review August 14, 2001 TLM DETECTORS We are planning to assemble a long loss monitor segment and perform sensitivity and plateau tests at site 38. We are also looking into the possibility of adding a small Cs 137 source inside one of the caps to be used as a “heart beat”.

NUMI Primary Beam Review August 14, 2001 TOROIDS  Used for absolute intensity calibration.  No material in the beam. Signal = 1/2 V per A. Accuracy: 3% absolute. Stability: 3%. Commercially available. Cost (Pearson Electronics) –Detector $5000 –Ceramic gap ---$1000 –Electronics------$2000 Est.

NUMI Primary Beam Review August 14, 2001 TOROID

NUMI Primary Beam Review August 14, 2001 INTEGRATOR CHANGES D. Schoo is prototyping a new version of the integrator module: differential input. 16 bit converter for extended dynamic range. Newer op amps with better offset and drift characteristics and low leakage capacitors were added.

NUMI Primary Beam Review August 14, 2001 SCHEDULE OF EFFORTS All scanners have been purchased. R&D work is presently underway for Multiwire, Loss Monitors, Toroid. Production will start after funds become available. Funds for Multiwire,Toroid and Loss Monitors will be available 4Q 2002 (FY2003). Instrumentation installation in 2004.

NUMI Primary Beam Review August 14, 2001 CONCLUSION A lot of work still needs to be done: In the case of multiwires –We have to finish testing the prototype, and then start assembling the final units. –Have a much more robust system to check and verify the appropriate timing event is selected. For BLMs we need to perform sensitivity/saturation high beam intensities i.e., booster RDF. Need to develop a heart beat system for the TLMs