LBNE Hadron Monitor and Target Hall Instrumentation Bob Zwaska February 4, 2014

Goals for this Presentation Discuss tolerances  Effects on systematics  How they are achieved Discuss the Hadron Monitor in detail  Most challenging tool for beam alignment  Other instrumentation mentioned, discussed more in other talks Set the stage for collaborative efforts on R&D and/or construction of the device(s) 2

Nominal Tolerances Initially derived from NuMI  Now under detailed scrutiny in beam simulations  Some will be relaxed or tightened for LBNE Different analyses will have different sensitivities on the tolerances, but we would like to specify as few numbers as possible  Near Detector analyses clearly vulnerable  Questions of beam power / detector size / run period 3

Meaning of Tolerances Tolerances can be confronted differently:  Design a device to be within tolerance Needs verification  If out of tolerance can conclude: Problem with design? Model the variation Correct the variation – e.g. alignment –Then need to model the uncertainty of the correction We can simplify design of components if we can be confident of having the means to measure variation and correct it  For example: it would be excruciating difficult to design a system to bring the proton beam within 0.45 mm of its desired position on the target without any instrumentation or correctors 4

Measurement Scheme Once tolerances are in hand and understood, we will develop a scheme to handle them  Designed precision of beam devices and systems Mechanical stability Temperature Control QA/QC extent  Instrumentation Custom-built devices (Target Hall Installation) Other devices upstream and downstream Designed features into devices to aid measurement  Integration Software tools to record, calibrate, and correlate measurements from disparate systems. 5

6 Target Hall Instrumentation Additional instrumentation in and near target hall to support beam operation  Commissioning  Beam-based Alignment  Beam Permit  Long-term Monitoring Interfaces with other instrumentation systems  Primary beam  Systems (RAW, air, temps)  Neutrino beam monitors Varying needs of reliability  Every pulse for beam permit  Monthly or yearly for alignment/commissioning Software is needed to bring everything together Use NuMI experience to plan for LBNE  Strengths and weaknesses  Have additional constraints in LBNE More powerful beam  Additional functionality, such as target decay

7 Shape of target and baffle Cross-hairs on horns, and horn neck Baffle thermocouples Budal Monitor Horn BLMs Hadron Monitor Muon Monitors BPMs Profile Monitors Toroids MINOS Near Detector Quick list of NuMI Tools/Instrumentation Features used “Target Hall” Instrumentation External Instrumentation

8 NuMI Hadron Monitor Sits at end of decay pipe 7x7 pixels 1m x 1m Helium ionization chambers  1 mm gap  Continuous flow High-radiation area  10s of GRad LBNE will have significantly greater ionization and radiation damage Heating is manageable This device is the most challenging

Hadron Monitor Sensitivity Has broad sensitivity to tolerances as it sits in remnant primary and secondary beams Most relevant parameters:  Intensity  Position  Width Most useful only in conjunction with other instrumentation and the features of beam devices 9

10 NuMI/LBNE Target/Baffle Shape Target and baffle stack produced high-contrast features  Gap between baffle and target  Horizontal fin Beam was scanned across features Response measured in instrumentation LBNE target will likely be similar  Needs to be validated for 1.2. MW Graphite protection baffle Graphite target Water cooling line 21.4mm 15.0mm 11.0mm 6.4mm Horizontal Fin

11 NuMI Commissioning First “Target Hall” beam task was to shoot the beam down the primary beamline and through chase, with no target  Demonstrate that we can see spot at Hadron Monitor  Pointing of the beam

12 NuMI Beam-Based Alignment Procedure  Scan proton beam across known features of beamline components Target & Baffle material Horn neck and cross-hairs  Use primary beam magnets, position monitors, and profile monitors  Use target hall instrumentation to correlate measured proton beam position with component features Target budal Monitors Loss Monitors in the target hall Hadron and Muon Monitors Target Horn 1 Baffle BPM x BPM y Profile BPM x BPM y Profile Horn Hadron Monitor 1077 Toroid Crosshair

13 e.g. NuMI Target Alignment Proton beam scanned horizontally across target and protection baffle Also used to locate horns Hadron Monitor and the Muon Monitors used to find the edges Measured small (~1.2 mm) offset of target relative to primary beam instrumentation. Pulse Height in Chamber (arb.) target baffle target baffle Graphite protection baffle Graphite target Water cooling line 21.4 mm 15.0 mm 11.0 mm 6.4 mm Horizontal Fin Target Horn Baffle p 

14 NuMI Cross-hairs On Horn1 upstream, Horn 2 upstream and downstream  12 or 36 mm thick in longitudinal direction Also used Horn 1 Neck

Hadron Monitor Environment Challenging in terms of:  Ionization rate  Radiation damage  Heat deposition  Residual Radiation Ideal device:  Resilient to the above  Linear in response  Sufficient resolution for alignment  Can be installed/removed remotely 15

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17 Particle fluxes of – / cm 2 a 10 us spill

Expect Doses in excess of 10 GRad Accident conditions deposit few 100 mJ/g 18

19 Expect residual dose > 100 Rad/hr

Design Options Gaseous ionization chamber is base design  Helium gas (flowing) gives least charge per particle Still, saturation due to space charge is a issue with these intensities Running at less than atmospheric pressure could ameliorate the space charge issue –Leads to complications in the design and operation – needs study Variation in gas quality can give a variable yield of ionization  Getting voltage in and signal out is most difficult issue NuMI used hardline cables with redundant polyimide/ceramic insulators Individual high-voltage feedthroughs for each pixel Suspect this as a failure mode 20 Lid Ceramic Plates PEEK Cap Stainless Nut Aluminum Gasket Stainless Bulkhead Ceramic Feedthrough Ceramic Washer

Other Design Options Sealed, individual detectors  Likely unsuitable due to changes in the gas composition – would need study  Could simplify pressure and integration issues  Still has problem with cabling Other detection options  Visible – needs rad-hard optics  Purely gaseous React components to produce a detectable by product –E.g aN 2 + bO 2 -> NO X Measure outside radiation area  ??? 21

Conclusion The Hadron Monitor is a crucial tool for limiting systematic uncertainties  Commissioning, alignment, monitoring  Part of a suite of instruments Hadron Monitor resides in a challenging environment  No present proven technology for the detector Gaseous ionization chamber may be adaptable at some complication  Alternate technologies must be explored Anticipate building prototypes and test beams  LBNE is now a substantial enough advance upon NuMI to require prototyping of the technology Unique item that may be ideal for collaboration with LBNE institutions  Can be limited to R&D, or include construction/operation 22

LBNE Hadron Monitor and Target Hall Instrumentation Bob Zwaska February 4, 2014

24 Cross-hairs intercept primary proton beam  Target must be out  Beam also scatters on Horn 1 neck Ion chambers / BLMs measures particle spray  One downstream of each horn  Signals were not always measureable from background This system needs some optimization for LBNE Horn BLMs

25 NuMI Budal Monitor Electrically isolated target Proton beam kicks off electrons and other charge particles from target segments Signal is read out  Proportional to beam intensity  Position dependent signal May not be possible on LBNE target  NOvA is investigating a Beryllium thermometer  Array of thin Be rods oriented horizontally, bolted to the target

26 NuMI Muon Monitors Located in alcoves after beam dump 9x9 (2m x 2m) ionization chamber arrays  3mm gap version of HadMon Plagued by gas purity and electronics problems Sees hadron contamination form dump  Cause by cracks Usefulness was never fully demonstrated  In LBNE, the regime of the ND group

27 NuMI target experience ( ZXF-5Q amorphous graphite ) Decrease as expected when decay pipe changed from vacuum to helium fill Each point in energy bin represents ~ 1 month running, time from 9/2006 Gradual decrease in neutrino rate attributed to target radiation damage No change when horn 1 was replaced No change when horn 2 was replaced Will check spectrum with new target in Sept. first ~4.5e20 of 6.1e20 POT on NT-02 shown on this plot

28 Target Decay in Muon Monitors Ratios of muon monitors seen to vary with target decay A simplified muon monitor behind the dump and in an alcove could provide an effective target decay monitor We need to be able to monitor target degradation without waiting for data to be processed form the neutrino detector

ND Secondary Monitors 29

30 Needs for External Instrumentation BPMs / profile monitors  Precise positions and widths at low-intensity  Able to look within the train NuMI has 6 batches, would be nice to look smaller  Optical survey data needed at time of commissioning Everything should be cataloged into ACNET and the datastreams, but we should also have a unified way of looking at the data

31 Budal Monitor Performance Horizontal Budal measurement consistent with Hadron Monitor Vertical measurement corresponds to baffle aperture – not horizontal fin  Several possibilities to affect Budal signal

32 Horn 1 Horizontal Position Horn 1 LM sees clean signal due to cross-hair Neck also cleanly resolved

33 Horn 2 Horizontal Positions Downstream cross-hair not resolvable in first scan  Upstream nub interferes Displace scan resolves the nub

34 Horn Vertical Positions Vertical scan looks for nubs Hadron Monitor RMS used for finding DS nub  LM could not extract signal  Not the beast measurement

35 Alignment Results Estimate effects on beam as a result of offsets measured  F/N ration is figure of merit  Use parameterization based on simulations  These are upper bounds as the worst effects are in higher-( )energy bins  Error budget is ~ 2% If beam were to be initially directed at (0,0) the budget would be exceeded However, beam is pointed using the alignment measurements  Target center horizontally  Baffle center vertically Larger offsets to optical survey were later found to be associated with settling and thermal variation

36 Long-term Running Hadron and Muon Monitors can see variations in target and horn  However, the detectors drift due to gas and electronics issues  We will need some subset of their functionality for LBNE Specific need: Target Decay

37 High-Intensity: Beam Permit System Inhibits beam on a rapid basis > 200 inputs Checks that radiation levels have not been exceeded  Prevents beam from being accelerated Beamline components – e.g. magnet ramps  Can prevent acceleration, but also extraction Beam quality in Main Injector  Position, abort gap This system may have to take more inputs for LBNE  E.g.: from Hadron Monitor