Note referaggio GSI/spin - SMILE/PAX/ASSIA ========================================== =================== Sat. Sep.09th, 2006 =================== - summary of SMILE/PAX documents ======================================================================== 1.- LoI esperimento SMILE, P.Lenisa, 20-07-2005 ======================================================================== - motivazioni - trasversalita` (pol. trasversa quark in protoni pol.) D-Y dileptoni in pbar-p doppio polarizzati - fattori forma regione timelike - necessari antiprotoni polarizzati HESR, facility FAIR al GSI unica possibilita` - Collaborazione: Ferrara, Erlangen, Julich, Dubna, Gatchina, Novosibirsk, Tbilisi, Yerevan 1. INTRODUZIONE ------------ * Spin Measurements in Interactions at Low Energy (SMILE) - buildup polarizzazione in anello di accumulazione tramite interazione con bersaglio interno polarizzato - protoni a COSY (FZJ, Julich), poi - antiprotoni all'anello AD (CERN) - protoni: risultati FILTEX (TSR) - fascio p 23 MeV - rate polarizzazione trsversa: dP/dt = (0.0124 +- 0.0006)/ora - bersaglio gassoso idrogeno polarizzato: 6 x 10^13 atomi/cm^2 - interpretazione controversa - idrogeno, 4 stati iperfini |m_J, m_I> (I=nuclear spin, J=L+S, electron); - due puri (1/2,1/2)=|1> e (-1/2,-1/2)=|3> pol.100% elettronica e nucleare - due combinazioni ortog. |2> = costh*(+1/2,-1/2) + sinth*(-1/2,+1/2) |4> = costh*(-1/2,+1/2) - sinth*(+1/2,-1/2) th = f(B/Bc), Bc = 507gauss (campo critico per idrogeno) pol nulla in campo esterno debole (regione Zeeman) pol. in campo intenso (regione Paschen-Bach) 2. MISURE A COSY CON PROTONI ------------------------- * bersaglio ANKE in COSY (in fase di commissioning) campo debole 10G-100G => usa solo stati puri |1> e |3>, come FILTEX - studio buildup polarizzazione in funzione di: - angolo accettanza - energia fascio - intensita`: - fascio p orbitante: 10^10-10^11 - bersaglio con cella accumulazione: 10^13-10^14 atomi/cm^2 - polarizzazione fascio misurata con polarimetro esistente - collisioni pp elastiche, asimmetrie - interpretazione: analisi PWA... * bersaglio HERMES campo magnetico guida forte 3kG - stato |1> + |2> polarizzato solo elettronicamente (nucl. nullo) stato |1> + |4>, |2> + |3> pol. solo nucleare (el. nullo) alternando |3> e |4>: cambia segno pol., campo magnetico invariato - problema deviazione fascio 300 MeV => campo guida longitudinale e polarizzazione longitudinale => necessita` siberian snake nella sezione retta di COSY opposta - bersaglio HERMES gia` equipaggiato con Breit-Rabi polarimeter (per dettagli vedi I.Brunn, diploma thesis su calibrazione bersaglio) - misura polarizzazione fascio: bersaglio gassoso non polarizzato e spettrometro di ANKE spegnimento adiabatico siberian snake => pol lungo l'orbita pol. fascio misurata da asimmetria destra-sinistra nelle collisioni elastiche protone-protone 3. MISURE CON ANTIPROTONI (AD, CERN) --------------------------------- - LoI in preparazione; pol. trasversale e longitudinale (siberian snake!) - misura sezione d'urto efficace buildup polarizzazione (NB piu` semplice e diretta che misura separata, in funzione dell'angolo di diffusione, di vari parametri di correlazione di spin) => pol. e densita` bersaglio, frequenza orbita - densita` da decelerazione fascio a cooling spento, oppure rate conteggi e sezione d'urto diff. misurata a LEAR => misura pol. fascio antiprotoni con polarimetro da sviluppare; - uso misure esistenti analyzing power in antiprotone-protone - oppure, sfruttando invarianza CPT - misura diretta analyzing power con - fascio antiprotoni non pol. - bersaglio protoni pol. (nota) - seguita da misure asimmetria - fascio antiprotoni pol.(incognita) - bersaglio protoni non pol. => con bersaglio interno protoni pol. e` possibile misurare anche correlazione di spin longitudinale Azz e ottenere direttamente la pol. longitudinale 4. PROGRAMMA --------- - 2006: - misure a COSY, bersaglio ANKE - trasferimento bersaglio HERMES - studi preparatori esperim. ad AD (polarimetro, macchina, bersaglio, snake, e-cool) - 2007: - misure a COSY, bersaglio HERMES - preparazione esperim. AD - 2008: - commissioning e misure ad AD - 2009: - misure ad AD ============================================================================= 2. LoI for the measurement of the spin-dependence of the ppbar interaction at the AD-Ring (PAX Collab., Julich November 2005) ============================================================================= - abstract - purpose: obtain parameters needed to build a dedicated Antiproton Polarizer Ring (APR) at FAIR/GSI, for QCD transverse spin physics (...) - measure antiproton polarization buildup using: - polarized hydrogen storage target - first meas. of the 2 total spin-dep. cross sections in ppbar in 50-200 MeV energy range 1. INTRODUCTION ------------ - physics interest: see abstract + theory of ppbar interactions + interpretation of unespected features of ppbar states produced in J/psi and B decays (...?) - QCD transverse physics program (FAIR/GSI) aims at luminosity of 10^31 - alternate methods ineffective - polar. Atomic Beam Sources OK for protons, not antiprotons - not OK for storage ring: - antiprot. from antilambda: P~0.35 (10^5/s) - scattering off liquid hydrogen target: P~0.2 (10^3/s) - Stern-Gerlach spin-splitting proposed, not observed yet - spin-filtering observed at FILTEX 2. PHYSICS CASE ------------ - (..., see introduction) - observables: total spin-dep ppbar cross-section (sigma_0, sigma_1/transverse, sigma_2/longitudinal) - separating elastic and annihilation contributions not feasible with the HERMES gas target... luminosity! - expectations from models: - buildup of 15-25% polarization buildup in 2 beam lifetimes in a dedicated large-acceptance storage ring ??? NON MI SEMBRA UN GRANCHE`: SUFFICIENTE PER TRASVERSITA`? ??? CONFRONTARE CON SCHEMI BRADAMANTE ET AL. 3. MEASUREMENT TECHNIQUE --------------------- - FILTEX result: - fascio p 23 MeV - rate polarizzazione trsversa: dP/dt = (0.0124 +- 0.0006)/ora - bersaglio gassoso idrogeno polarizzato: 6 x 10^13 atomi/cm^2 - polarization buildup equations (assuming no depol...): P(t), depending on tau_1(transv), tau_2(long) - target density - revolution frequency - sigma_1(transv), sigma_2(long) => from tau_1, tau_2 obtain sigma_1(transv), sigma_2(long) 4. EXP.TAL REQUIREMENTS FOR THE AD-RING ------------------------------------ - low-beta section (beta_x,y ~ 0.3) for the Polarized Internal Target (PIT) - HERMES PIT operated at weak guide field (10G) - siberian snake (solenoidal + 4 skewed quadrupoles) - electron cooling to compensate for m.s. in the internal target upgraded from 30 to 120 keV to cover 50-200 MeV - intensity increase through stacking (10^8 stored antiprotons for luminosity of 10^28 cm^-2 s^-1) to be able to measure polarization after 2 beam lifetimes (with "thicker" unpolarized target) 5. POLARIMETRY ----------- - beam polarimeter: see ANKE spectrometer at COSY ------------------------------------ (see COSY proposal #152, 159 etc, http://www.fz-juelich.de/ikp/anke/) ??? OTTIMISTI - pronosticano antiprotoni pol.30% a HESR-FAIR electron-to-proton transfer polarization interpretation of the FILTEX results (still acceped ???) ??? costruzione di APR gia` nel 2008-2009 ??? ------------------------------------ self-triggering silicon tracking telescopes - inside ultra-vaccum chamber, 25 mm from the beam - DeltaE/E proton-deuteron identif. ??? E` NECESSARIA QUESTA FUNZIONE NELLE MISURE AD??? ??? CINEMATICA ETC ??? - particle tracking over wide range (2.5 MeV - 40 MeV spectator(*) protons, or mips) (*) protons from deuterons, in pn interactions...! - combination of very thick/very thin double sided strip detectors (5-25 mm ??? down to 69 mum ?) - proton goes through first thin layer, stops in second layer (tracking + energy measurement => four-momentum) - 1st layer 51x66 mm2, 69 mum thick, pitch 400 mum in coinc. with 2nd layer: proton thresh 2.5 MeV - 2nd layer 51x66 mm2, 300 (500) mum thick, pitch 400 mum: stops protons up to 6.3 (8) MeV - 3rd layer 64x64 mm2, 5.1(10) mm thick (Si(Li)), pitch 666 mum stops protons up to 40 MeV - ...several purposes... polarimeter: - 2 protons from (quasi-)elastic scattering 6. MANPOWER, COST, TIMETABLE ------------------------- - manpower & cost: PAX collaboration (not all required...) details in the full proposal, to be submitted by summer 2006; table: ----------------------------------------------------- 2 Straight Sections weeks kEuro ----------------------------------------------------- 2.4 Slow control 16 120 2.5 Vacuum System Straight Sections 6 500 2.6 Target Diff Pumping System 10 500 2.8 10 Quadrupoles low-beta Section 400 2.9 Electronics Experiment 150 ----------------------------------------------------- 3 Electron Cooler ----------------------------------------------------- 3.1 Upgrade existing Cooler to 120 keV 40 200 ----------------------------------------------------- 4 Siberian Snake ----------------------------------------------------- 4.2 Existing Snakes Decision Finding 6 6 4.3 Transport & Hardware Tests 6 7 4.6 Power Supplies and 4 skewed Quadrupoles 100 ----------------------------------------------------- 7 Commissioning: 12 weeks ----------------------------------------------------- 7.2 Miscellaneous Electronic Material 60 ===================================================== Invest Total 2163 Travel Costs 180 ===================================================== (???no mention of detector and target costs???) - timetable: - 2006-07: design and tests - 2008: test low-beta section, with PIT and siberian snake at COSY - 2009: installation of components at AD, commissioning 2 months of beam time - 2010: 2 months of beam time + beam commissioning (weekends) ============================================================================= 2. LoI for spin-filtering studies at COSY (PAX Collab., Julich April 2006) ============================================================================= 1. INTRODUCTION ------------ - measure buildup 20-800 MeV proton pol. by filtering technique - two conflicting theories, need experiment !!!: - Mayer: QED process, spin transfer from electrons to protons in a stored gas target; cancellation?... - Budker-Julich: only nuclear interactions contribute - etc.etc. (see LoI) 2. PHYSICS CASE ------------ - subtleties in Mayer approach - scattered beam particles at small angles remain in the beam => mixture of transmitted beam and scattered beam pol. - PIT: atoms contain polarized electrons; non-negligible interaction with circulating beam pol. (comparable size!!!) - also: Coulomb-nuclear interference effects... ==> sigma_1 83 mb instead of 122 mb? and, with ep and pp interactions: 83 - 70 +52 = 63 mb (final agreement with FILTEX... ?! recent re-analysis => 72 +- 6 mb) - alternative explanations (...) => 83-89 mb - how to distinguish? - target: hyperfine states combination allow selective polariz. of electrons or protons - with 2 mrad acceptance, predictions differ by a factor 3 - possible isoscalar deuterium target? 3. MEASUREMENT TECHNIQUE --------------------- - see LoI 4. EXPERIMENTAL REQUIREMENTS AT COSY --------------------------------- - new low-beta section with PIT, Siberian Snake for long.pol. - HERMES PIT with weak 10G field NB: ANKE PIT has too long beam lifetime !!! - target polarization: to be measured with beam ramped up at 800 MeV (larger analyzing power) - preliminary measurements with the ANKE PIT stacking => 1.5 x 10^10 initial protons after 5 lifetimes => 10^8 circulating protons => 50 elastic interactions/s with HERMES PIT project 1500 elastic interactions/s => expect small P ~ 0.015 after 5 lifetimes => need ~ 2x10^6 events in beam polarimeter (~20 min.) ============================================================================= 3. PAX Status Report: spin-filtering studies at COSY (P.Lenisa, CSN III, Roma, 30-05-2006) ============================================================================= - comissioning of ANKE PIT - storage cell: collaboration Ferrara-FZJ (~2x10^13 atoms/cm2) - Lamb-shift (target) polarimeter - Ferrara contribution: ion deflector - spin filtering at COSY - goal - discussion of filtering method and FILTEX result dP/dt = (0.0124 +- 0.006) /ora sigma_1 = (73 +- 6) mb - interpretazione... - (1) selective removal (nuclear) - (2) small angle scattering into acceptance - (3) pol.transfer from electrons Meyer: => 83+52-70 = 65 mb (...): cancellazione effetti (2),(3) => 85.6 mb - per decidere tra i due modelli - misura sigma e pol al 10% a diverse en. - pol. selettiva protoni ed elettroni nel bersaglio (difficile) - new interaction point - HERMES target: a Julich da marzo 2006 - comparison ANKE/new inter. - filtering time, polarization, rate, meas.time (26 min => <1s) - experimental set up (up-down asymmetries) - det. concept: elastic scattering; recoil <8 MeV; silicon tracking - ANKE silicon detector telescopes - preparation of AD expt - low-beta section - pol. target (HERMES) - detector: use ANKE development; need also forward detector for AD ??? - siberian snake - beam lifetimes studies at COSY needed - infn: Ferrara (+Roma, Bari?); target; silicon tracking telescope? - funding - timeline - fall 2006: technical proposal a COSY - spring 2007: technical proposal AD - 2006-08: design, construction at COSY - 2008: spin filtering measurements at COSY, commissioning of AD expt - 2009: installation at AD - 2009-2010: measurements at AD ============================================================================= 4. PAX-Note-3/2006 Towards spin-filtering Experiments at COSY and AD (PAX Collaboration, Julich, June 23, 2006) ============================================================================= 1. ORGANIZATION (PAX) ------------------ - P.Lenisa, co-spokesperson - Capiluppi: target deputy - Cantalbrigo: detector deputy - Tagliente: slow control deputy - other wg: DAQ, simulation and data analysis, accelerator, theory 2. EXPERIMENTAL PROGRAM -------------------- - COSY, AD - time table: ------------------------------------------------------------------ 2006-2008 Design and construction phase. Fall 2006 Proposal to COSY Program Advisory Comittee. Summer 2008 Installation of new low-beta section, PIT, BRP, and detection system at TP1 of COSY. Fall 2008 Full Proposal to SPS Committee at CERN. Fall 2008 - Summer 2009 Polarization buildup studies at COSY. Fall 2009 Installation of all components at the AD, including the Snake. Spring 2010 2 months of beam time at the AD with transverse target polarization. Fall 2010 2 months of beam time at the AD with longitudinal target polarization and the Siberian Snake. ------------------------------------------------------------------- - theoretical expectations (responsibilities for evaluations...) - pp observables and spin filtering (nothing new, see previous notes) - a useful table for measurement strategy: Table 2: Strategy for the polarimetry of the measurements of the four categories (Weak Transverse,Weak Longitudinal, Strong Nuclear, Strong Electron) for the polarized Hydrogen target. - polarized deuterium target? 3. CONCEPTUAL LAYOUT ----------------- - "0-th order design"...! no detail... 4. Low-beta section & superconducting quadrupoles ---------------------------------------------- 5. LATTICE STUDIES --------------- 6. LIFETIME STUDIES AT COSY ------------------------ 7. BEAM DIAGNOSTICS ---------------- 8. POLARIZED TARGET ---------------- - atomic beam source (Nass, Capiluppi) - target pol.: purely nuclear vs purely electron - Breit-Rabi target polarimetry (Nass, Capiluppi, Lenisa, et al.) - storage cell (Lenisa, Carassiti, Ciullo, et al) - hold field (Capiluppi, Statera, Lenisa, et al) - detector layout (??? completamente ideologico, nessun dettaglio) - vacuum system 9. DETECTOR SYSTEM --------------- - Forward detector (russi...): solo lista di cose da fare... - Monte Carlo simulations " " " " " - DAQ, detector electroncs, analysis software - silicon telescopes (STT) - prototype STT (silicon telescope) after parameters are ready (Cantalbrigo e Cotta + tedeschi) - STT production (after prototype tests) (Cantalbrigo e Cotta + tedeschi) - electronics (russo?) ============================================================================= 4. preventivi 2007 ============================================================================= ------------------------------------------------------------------------ Bari ------------------------------------------------------------------------ CA: Sistema d'alimentazione rivelatori e polarimetro, PLC per sistema slow control 15,0 ------------------------------------------------------------------------ Ferrara ------------------------------------------------------------------------ MI: Contatti con gruppi nazionali, ditte per lavorazioni. 10,0 ------------------------------------------------------------------------ ME: coordinazione come Spokesperson (e Technical Coordinator). P.Lenisa: 3 mese/uomo. Sviluppo e realizzazione bersaglio polarizzato, cella di accumulazione, polarimetro di Breit-Rabi. - G. Ciullo: 1 mese/uomo - M. Capiluppi: 7 mese/uomo - tecnologo: 1 mese/uomo Disegno e contatti rivelatore telescopio di silicio. - M. Contalbrigo: 1 mese/uomo - L. Barion (PhD): 4 mesi/uomo (forfettario) - tecnologo: 1 mese/uomo Allestimento esperimento e partecipazione a turni di misura esperimento ANKE. 2 turni di 2 settimane per 4 ricercatori: 4 mesi/uomo 23,5 70,0 26,0 31,0 ------------------------------------------------------------------------ ME totale 150,5 ------------------------------------------------------------------------ cons: Sviluppo e test di cell per nuovo punto interazione a COSY e AD (in collaborazione con COSY). Consumi bersaglio e polarimetro (a meta' con COSY). Cavetteria per test rivelatori. Consumi camera pulita test per test rivelatori (filtri e manutenzione ordinaria) 10,0 10,0 5,0 5,0 ------------------------------------------------------------------------- cons totale 30,0 ------------------------------------------------------------------------- INV. Elettronica per acqusizione 5 rivelatori di silicio. 65,0 ------------------------------------------------------------------------- Camera per test rivelatore. 5 rivelatori di silicio necessari per la costruzione di due telescopi completi (4 moduli per il detector piu uno spare), corrispondenti a meta' della parte in avanti del rivelatore 7,0 40,0 ------------------------------------------------------------------------- App. 47,0 ------------------------------------------------------------------------- Totale 302,5 -------------------------------------------------------------------------