10 September 2003Mark Oreglia/ICAR review1 The University of Chicago/ Argonne National Lab ICAR Activities Who we are Muon accelerator issues: – Muon cooling.
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10 September 2003Mark Oreglia/ICAR review1 The University of Chicago/ Argonne National Lab ICAR Activities Who we are Muon accelerator issues: – Muon cooling theory – Profile monitoring of intense beams Smith-Purcell Free Electron Laser Linear electron collider development: – electron source design – LC machine design/administration/education – hadron calorimetry and energy flow technique
10 September 2003Mark Oreglia/ICAR review2 U of C/ANL Personnel University of Chicago: –Mark Oreglia (Professor, co-PI) … LC, muon/LC instrumentation –Yau Wah (Professor) … Smith-Purcell; JHF development –Kara Hoffman (RA) … beam profile monitor; neutrino factory –Bud Kapp (RA) … Smith-Purcell –Yin-e Sun (Grad Student) … electron sources –Assorted undergraduate students (6, so far) Argonne National Laboratory –Kwang-Je Kim (Senior Scientist; Professor/UofC) … Smith-Purcell; accelerator theory and education Chung-Xi Wang (RA) … muon cooling theory Future additions likely: –Ed Blucher (Assoc. Prof.) and Young-Kee Kim (Professor)
10 September 2003Mark Oreglia/ICAR review3 Kwang-Je Kim’s Group Activities Part A: Ionization cooling theory –K.-J. Kim and C.-x. Wang (ANL) Part. B: Smith-Purcell Laboratory –O. Kapp, A. Crewe,Y.-e Sun (student),Yau Wah Part C: Graduate Physics Course “ Accelerator Physics and Technologies for Linear Colliders” –Kwang-Je Kim Part D: Participation to flat beam generation experiment at FNPL –Y.-e Sun (student)
10 September 2003Mark Oreglia/ICAR review4 Part A: Ionization Cooling Theory Theoretical effort by K.-J. Kim and C.-x. Wang A comprehensive linear theory for ionization cooling taking into account –Transport in cooling lattice (Hamiltonian) –Dissipation and fluctuation in absorbers –Emittance exchange via dispersion and wedge absorbers –Beam angular momentum Moments expressed in terms of five invariant emittances
10 September 2003Mark Oreglia/ICAR review5 Emittance Exchange
10 September 2003Mark Oreglia/ICAR review6 Further Theoretical Topics Recursive evaluation of beam transport lattice consisting of extended elements ( such as solenoids used in ionization cooling channels) Rigorous treatment of magnetic field expansion for curved reference orbits…Provided bench-marking of ICOOL Extensive Publications including two PRLs
10 September 2003Mark Oreglia/ICAR review7 Selected papers on related developments C.-x. Wang and K.-J. Kim, COOL03, NIM A (2003) Beam envelope theory of ionization cooling C.-x. Wang and K.-J. Kim, PRL 88(18) 184801 (2002) Linear Theory of Ionization Cooling in 6D Phase Space C.-x. Wang and K.-J. Kim, NIM A503 401 (2001) Linear theory of transverse and longitudinal cooling in a quad. channel C.-x. Wang and K.-J. Kim, PRE 63 056502 (2001) Recursive solution for beam dynamics of periodic focusing channels C.-x. Wang, NIM A503 409 (2001) Dispersions in a bent-solenoid channel C.-x. Wang and L.C. Teng, PAC’01(2001) Magnetic Field Expansion in a Bent-Solenoid Channel K.-J. Kim and C.-x. Wang, NIM A472 561(2001) Progress in the Linear Beam Dynamics Study of Ionization Cooling Channel K.-J. Kim and C.-x. Wang, PRL 85(4) 760 (2000) Formulas for Transverse Ionization Cooling in Solenoidal Channels
10 September 2003Mark Oreglia/ICAR review8 Part B: Smith-Purcell Laboratory An electron microscope–based Smith-Purcell generator for a compact far IR source Retrofitted the sample chamber of a Cambridge S-200 scanning electron microscope with a grating Radiation transported via a polyethyene window to a bolometer Observed spontaneous Smith-Purcell radiation after carefully eliminating the effects due to blackbody radiation. (c.f., Dartmouth claim on high-gain behavior) We are evaluating: –Several options for electron sources (heated tungsten tip, Lab6, Thermionic field emission) –Electron beam recovery system Preparing proposals for other funding agencies
10 September 2003Mark Oreglia/ICAR review10 IR detector FEL Bud’s lunch
10 September 2003Mark Oreglia/ICAR review11 Part C: A Graduate Physics Course “ Physics and Technologies for Linear Colliders Physics 575 during winter 2002 Lectures by experts in the field –S. Holmes, K.J. Kim, T. Raubenheimer, J. Rosenzweig, L. Emery, J. Wang, L. Lilje, F. Zimmermann, V. Shiltsev, W. Gai Lecture notes in the course web page –http://hep.uchicago.edu/~kwangje/phy575.html
10 September 2003Mark Oreglia/ICAR review12 Part D: Flat Beam Generation A novel beam manipulation technique proposed by Y.Derbenev A flat beam ratio (FBR) of 50 has been achieved at FNPL ( FNAL-NIU Photocathode Laboratory). Yin-e Sun is investigating effects reducing FBR –Energy spread, space-charge effects, breaking of cylindrical symmetry To improve the flat beam ratio to >100.
10 September 2003Mark Oreglia/ICAR review13 Schematic rendition of the layout at Fermilab for flat beam experiment x = A cos z y = A sin z A cos z A sin ( z+ /2) flat beam vortex beam
10 September 2003Mark Oreglia/ICAR review14 FermiLab/NICADD PhotoInjector Layout taken from PAC01 paper of D. Edwards etc.
10 September 2003Mark Oreglia/ICAR review15 Flat electron beam profile at 9.6m from the cathode (XL6) and horizontal and vertical beamlets used for emittance measurements downstream at XL7 and XL8. The transverse emittance ratio is about 41 in the example shown here.
10 September 2003Mark Oreglia/ICAR review16 Mark Oreglia’s Group Activities Started out with muon cooling instrumentation R/D –Bolometric beam profiler Made progress, but Kara developed another idea … –Thin diamond beam profile monitor First time diamond used for intense beams More versatile application than just muon channel –FNAL machine groups very interested Cheaper than single-particle application Then Oreglia got involved in the Linear Collider –Co-chair of American LC Physics Group; US Steering Ctte –Member of International LC parameters ctte –Working on hadron calorimetry; RPC development/assessment + energy flow techniques
10 September 2003Mark Oreglia/ICAR review17 The challenge of profiling beam in muon cooling channel While disturbing the beam as little as possible measure: intensity size/profile (in 2 dimensions?) timing between bunches or pulses The detection medium must be radiation hard. The beam must be accurately measured in an environment with a lot of noise from rf cavities, etc. The profiler and associated readout/power cables must fit within the design of the cooling channel. Muons are difficult to detect.
10 September 2003Mark Oreglia/ICAR review18 IDEA #1
10 September 2003Mark Oreglia/ICAR review19 Bolometry: proof it works 0.8 V 0.8 V 10 ms Carbon 0.8 V 0.8 V 20 ms Nickel “bolometer” (actually a commercially made thin film nickel thermometer) Xe flashlamp lenses cryostat filter electronics Signal or background? Look for thermal dependence (i.e. change in signal size, time constant). Polarity: carbon’s electrical resistivity increases with temperature while nickel’s decreases. Signal or background? Look for thermal dependence (i.e. change in signal size, time constant). Polarity: carbon’s electrical resistivity increases with temperature while nickel’s decreases. (“homemade” from graphite foil or colloidal carbon) @20K
10 September 2003Mark Oreglia/ICAR review20 Materials Studies We’ve researched traditional and non-traditional materials –Measured properties Developed thin film techniques Constructed pulse simulators –Laser calorimetry simulation – ANL e-beam tests Constructed temperature controller to simulate cooling channel –LHe cryostat + temperature controller
10 September 2003Mark Oreglia/ICAR review21 Amplifier Development To match time constants and minimize noise, we have developed special purpose amplifiers in the Enrico Fermi Institute Electronic Design Group (Harold Sanders!) X600 amplification Baseline subtracting They work!
10 September 2003Mark Oreglia/ICAR review22 Beamtests at ANL: setup copper block with 1/8 ” hole used to mask off beam and shield the thermometer Pulses nominally 10 nA in duration--we tried to reduce inductive noise by elongating pulses to lower instantaneous current beampipe cryostat temperature controller vacuum pump LH2 tank bolometric film /pulse 840 nA @ 30 Hz
10 September 2003Mark Oreglia/ICAR review23 Beamtests at ANL: results see opposite coefficient for Ni vs C … for a while learned that intense e- beam modifies graphite Some interesting results here minimizing inductive noise will need more design work … but, in principle, the technique shows some promise
10 September 2003Mark Oreglia/ICAR review24 0.30 - 0.35 K 0.25 - 0.30 0.20 - 0.25 0.10 - 0.15 0.15 - 0.20 0.00 - 0.05 0.05 - 0.10 2 beam radius Signal expectation: the linac test facility (protons!) GEANT3 simulation Corresponding % resistivity change in bolometer strip Platinum TCR curve
10 September 2003Mark Oreglia/ICAR review25 Advantages: doesn’t disturb the beam; inexpensive; robust Drawbacks: must be applied to absorber window for heat sinking – could be an issue mechanically/safetywise and cannot be removed or replaced small signal, particularly for more diffuse beams metal strips provide challenge in large electromagnetic noise environment large thermal time constants do not allow for measurement of timing information Bolometry findings Future Plans: NIM publication in preparation … sort of … we still have a number of measurements to perform
10 September 2003Mark Oreglia/ICAR review26 New Idea (Kara, of course!): Diamond is prized for more than just its sparkle (high refractive index)… low leakage I very fast readout no p-n junction needed low capacitance rad hard, strong no cooling hard insensitive to ’s >220nm Makes a great particle detector!
10 September 2003Mark Oreglia/ICAR review27 - - - - + + + + diamond substrate ~500 m thick (when used as a microvertex detector) E (>1 V/ m) sputtered metal strips/pixels (400 angstroms of titanium or chromium coated with 4000 angstroms of gold) solid electrode Ionizing radiation (36 e-h pairs per m per mip) Anatomy of a diamond substrate microstrip detector… Essentially a very compact solid-state ionization chamber. IDEA #2
10 September 2003Mark Oreglia/ICAR review28 Diamond as a beam profiler? sensitive (2 coordinate?) measurement fast (subnanosecond ~40ps) intrinsic response might allow temporal beam profiling, in addition to current and position measurements free standing-accessible low Z- very little beam loss has been demonstrated to be rad hard to a proton fluence of at least relatively huge signal (too huge??) Diamond has not yet been realized as a microvertex detector because the signal size is small compared with silicon and single particle detection efficiency is required. However, single particle efficiency is NOT required for a beam profiler.
10 September 2003Mark Oreglia/ICAR review29 Polycrystalline CVD Diamond growth side substrate side induced charge: dx= distance e-holes drift apart = carrier mobility, = carrier lifetime Carrier lifetime effected by: size of individual crystals- grain boundaries in grain defects and impurities
10 September 2003Mark Oreglia/ICAR review30 “black” diamond polished high purity diamond unpolished diamond diamond membrane (with person peeping through) What kind of diamond is best suited as a beam profiler? signal size could be limited by decreasing the electric field this approach is destructive to timing information diamond with short carrier lifetime small gives faster response at the expense of efficiency much cheaper as thin as possible less charge produced per mip voltage required for maximum carrier velocity is proportional to thickness easier to dissipate heat diamond “membranes” can be made 1 m thick We want to minimize the signal while exploiting the timing information.
10 September 2003Mark Oreglia/ICAR review31 Detector fabrication: sputtering electrodes We have fabricated our first prototype from a piece of 500 m x 11mm x 11mm detector grade CVD diamond that was manufactured by DeBeers. Leads were sputtered at OSU using a shadow mask—finer segmentation could be achieved with a lithographic mask.
10 September 2003Mark Oreglia/ICAR review32 Towards a diamond testing program… R&D areas: Application specific material will need to be developed, along with fast electronics. Over what range of intensity measurements could diamond be useful? (space charge effects?) How radiation hard is it? Near term plans: We are in the process of obtaining some diamond with shorter carrier lifetimes. We plan to study the behavior of our prototype in a beam test at Argonne this summer. R&D areas: Application specific material will need to be developed, along with fast electronics. Over what range of intensity measurements could diamond be useful? (space charge effects?) How radiation hard is it? Near term plans: We are in the process of obtaining some diamond with shorter carrier lifetimes. We plan to study the behavior of our prototype in a beam test at Argonne this summer.
10 September 2003Mark Oreglia/ICAR review33 Linear Collider Activities We moved into this area when HEPAP announced this would be the next US accelerator project An important US LC workshop was hosted by the University of Chicago in January 2001 … ICAR-sponsored Oreglia, Blucher, Y.K. Kim sit on LC organizational groups LC scope: Oreglia edited the US “scope paper” defining required machine parameters; now participating in the international ctte ICAR funds have been essential in supporting this activity Physics+Detector work: –Focusing on hadron calorimetry: Fits in with ATLAS-related activity Working on RPC development with ANL (Jose Repond) –This preliminary work will likely leverage some NSF support
10 September 2003Mark Oreglia/ICAR review34 University of Chicago RPC Studies Development of a Digital Hadron Calorimeter for the LC based on Resistive Plate Chambers Work in conjunction with ANL (Jose Repond) Abigail Kaboth … undergrad! Ed Blucher Mark Oreglia Sasha Glazov
10 September 2003Mark Oreglia/ICAR review35 RPC R/D First built by Argonne … we are building our own prototypes –Want to look for material damage; investigate chamber performance They are a very cost-effective technology for LC application, but The technology has a very checkered past Useful technology for other experiments too (neutrino,…) –Double gap RPC –Three fishing line spacers in each gap We are mixing our own gases – permits us to optimise for avalanche mode (new-ish application) Electronics Design Group is developing DAQ electronics … all supported exclusively by ICAR! …… and this “redundant” work is learning new things about RPCs!
10 September 2003Mark Oreglia/ICAR review36 UoC Data Acquisition Setup Trigger Counters RPC Drift Chamber Drift Chamber Track, 250 m resolution x z y
10 September 2003Mark Oreglia/ICAR review37 Photographs Abby RPC
10 September 2003Mark Oreglia/ICAR review38 We saw significant dips in the efficiency of the RPC around the fishing wire spacers. Bin size is.375 mm. Dip is wider than spacer. Efficiency Position (mm) 7400 V 7600 V Half width is 1.8 mm Spacer Inefficiencies
10 September 2003Mark Oreglia/ICAR review39 Efficiency Position (mm) High Voltage on this side Finding Current Paths
10 September 2003Mark Oreglia/ICAR review40 Calculating Apparent Voltage Drop Using drift chamber data, we calculated apparent voltage as a function of position from the tanh curve. We see a variation of about 100 V, about 1%. Position (mm) Voltage (V)
10 September 2003Mark Oreglia/ICAR review41 Possible Causes Variations in internal geometry and construction –Plates not being exactly parallel –Damage on glass from experimentation Actual voltage drop due to current flow –Through fishing line spacer –Because of moisture in gas
10 September 2003Mark Oreglia/ICAR review42 Epilogue ICAR funds have permitted us to move into exciting new directions and take important roles in the Muon Collaboration, the Linear Collider project, and new accelerator development We have been able to support 2 postdocs and students only because of the ICAR funding We plan to continue research on the original projects, with some additions and redirections: –Advanced accelerator theory beyond just muon now KJK working to establish a center for accel research –Beamline instrumentation has taken a new, more promising direction … thin diamond detectors –Development of RPC calorimeters now fully underway Working to build a 1m 2 prototype for beam testing –Just starting studies of energy-flow analysis and optimisation of LC detector systems
10 September 2003Mark Oreglia/ICAR review43 Mutual Benefits from ICAR Funding ICAR funding has permitted us to address problems which, in the majority of cases, our traditional funding agencies denied This results in novel developments; in our case: –New beamline instrumentation New knowledge of material properties and participation by new people (materials scientists, nano centers, …) –New tools for materials research (Smith-Purcell instrument) –New tools for accelerator builders (theory, e-injector, cold ) –New tools for HEP experimenters (next-generation calorimetry) Facilitates new types of student training And benefits Illinois: –Local industry participates or gets business –Illinois is a candidate site for LC And if not the site, our work helps ensure FNAL major player –Illinois students and teachers participate: learn and contribute
10 September 2003Mark Oreglia/ICAR review44 Extra Slides
10 September 2003Mark Oreglia/ICAR review45 Equation of Motion Phase space vector
10 September 2003Mark Oreglia/ICAR review46 Hamiltonian of the Focusing System solenoid + dipole + quadrupole + RF + absorber dipole quadrupoler.f. solenoid, Lab frame Rotating frame,,,
10 September 2003Mark Oreglia/ICAR review47 Emittance Evolution Near Equilibrium Parametrized by Five Invarients Guidance for developing cooling channel with emittance-exchange
10 September 2003Mark Oreglia/ICAR review48 Diagram of the RPC
10 September 2003Mark Oreglia/ICAR review49 Major Budget Items Part A… Fund transfer to ANL to support C.-x. Wang Part B …Partial (40-50%) salary support for O. Kapp, equipments and supplies, technician charges Part C…Travel support for lecturers Part D…Stipend for a graduate student Domestic and international travels Equipment for Smith-Purcell project
10 September 2003Mark Oreglia/ICAR review50 tails due to carrier lifetimes Charge collection efficiency Charge collection efficiency is a product of: d -carrier drift velocity- a function of the applied electric field up to a saturation velocity -carrier lifetime-a function of diamond quality- commercially available diamond improving with time