CEDAR PROJECT STATUS FROM BEAM WG

CEDAR PROJECT STATUS FROM BEAM WG
Lau Gatignon CErenkov Differential counters with Achromatic Ring focus

K12 Beam Working Group – CEDAR Status
Outline Introduction, basic principles of CEDAR Why Hydrogen? Hydrogen safety Simulations of existing CEDAR (with H2) Suggested modifications PMT studies Readout Cost information Outlook L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Basic principles The CEDAR is used to identify Kaons in the beam using Cerenkov light The Kaons are a small fraction of the total flux (in units of 106 per spill): Protons Kaons → 6.6% only Pions Electrons Muons The CEDAR is blind to all particles except Kaons (i.e. the wanted type) A diaphragm blocks the light from other particles Nevertheless the rate is very high: / 3 sec = 50 MHz Two types of CEDAR exist (as AB standard): North type GeV/c, filled with He at ~10 bar, q ~25 mrad West type up to 150 GeV/c filled with N2 at < 1.7 bar, q ~31 mrad CEDAR requires a parallel beam for adequate performance L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Radial impact point at diaphragm
must be independent of emission point (Z) Optics optimisation must be zero ( rd equal for all Zo !!! ) where: L1 = dist. diaphragm – chromatic corrector L2 = dist chromatic corrector – mirror R1, Rm = Rcurv of entrance face , mirror plane mangin mirror Rc = Rcurv of chromatic corrector lense L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Optics requires chromatic corrections depending on gas and quartz n(l) Made precise parametrisations based on many more data points: L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

l [A] He N2 H2 L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Example of a pressure scan at 75 GeV/c in H2 beam (October 2007): p+ p K+ L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Why Hydrogen ? Absolute necessity to minimize material on beam line The hope is that the 4x lower pressure allows thinner windows (we hope 100 instead of 400 mm Al) Helium Nitrogen Hydrogen Pressure [bar] 10 1.7 3 AL window thickness [mm] 2x400 2x100? AL window thickness [10-3 Xo] 9 2.5 ? Thickness gas [10-3 Xo] 9.5 30 2.5 Total thickness [10-3 Xo] 18.5 39 5 (?) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Comparative effect on the beam of multiple scattering in the various
CEDAR options we have considered (tuned to 75 GeV/c K+): CEDAR-type Gas filling Length(m) Windows Total x/x0 RMS scatt.angle H +V-plane (mr) CEDAR-N bar He x0.4mm Al CEDAR-W bar N x0.05mmAl CEDAR-W bar H x0.15mmAl For comparison: GigaTracker SPIBES Si ~0.4mm Total CEDAR-W(N2) + 3 SPIBES CEDAR-W(H2) + 3 SPIBES L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Hydrogen safety aspects
A CEDAR discussion with SC-GS took place on 5 January 2005 Present: N.Doble, L.Gatignon, A.Desirelli (SC-GS), J.Gulley (SC-GS) This informal discussion aimed at establishing a first contact with the safety experts to get their input and advice concerning a potential future implementation of a CEDAR counter in the TCC8 area, filled with hydrogen gas at pressures up to 3 bars absolute. After having explained the basic purpose of a CEDAR counter in the proposed experiment and the reasons for changing to hydrogen, we discussed the different technical and safety aspects that would need to be considered. ……see next slide As a tentative timescale we suggested that such a device would need to be operational in 2007. At the time of the meeting no major fundamental obstacle or show-stopper was identified, but obviously a final answer would require a careful and complete study. Indeed a list of questions and a number of tasks were identified: Action: We should as soon as possible prepare a ‘dossier’ for SC-GS. L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

List of points to be addressed: Provide SC-GS with construction drawings and material certificates or definitions of the materials used. This includes the type of steel, the windows material and thickness (SC-GS may provide design input or help) and the type of seals. The insulation material should not produce toxic black smoke. Note that polyurethane foam is acceptable in small quantities whereas polystyrene is forbidden. A sample of the insulation material should be made available for analysis by SC-GS. Provide drawings and/or details of all electrical equipment (HV, motors). Look at all possible leak scenarios and propose actions. This includes leaks into the beam line, which must therefore use hydrogen rated pumps. A hydrogen venting system must be available in TCC8 to cope with pressure changes (including unforeseen pressure rises) and the placing of the hydrogen supply bottle must be considered. The relevant parts of the CEDAR counter should be housed in an inert enclosure. It should be small enough (local !) that it does not become a confined space problem in itself. Its walls should be thin to avoid danger in case of explosion. Provide draft hydrogen filling and shutdown procedures, including emergency scenarios L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Conclude: Hydrogen is a serious complication But apparently not a showstopper from the safety point of view This discussion should be taken up again Recently J.Gulley confirmed (orally) that the rules are still the same as in 2005 But does a CEDAR work with Helium? (Chromatic corrections?) Cedar – North or West? What does one have to modify How is the rate distributed Need Optimization and MONTE CARLO simulation L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

(Cedar-N, He filled) Optimisation of optical parameters: X2 Used Used Rmangin [mm] Z chromatic corrector Note: with i = 2800, 3500, 4400 Angstrom L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Cedar-N, Helium R at diaphragm [mm] 2800 A 3500 A 4400 A Rcurv of mangin mirror [mm] L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Cedar-West Optimisation for H2 and N2 yield very similar results Base design on Cedar-W X2 H2 Used N2 R mangin mirror [mm] L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

CEDAR first Optics Simulation Generate rays according to momentum, mass, n-1, Pressure Uniform over length of counter, uniform in l in Å Use fitted l-dependence of n-1 for quartz, Helium, Hydrogen Track photons through all optics elements Apply cut at diaphragm Project ray through quartz window onto PM plane Possibility to analyse per ray or to simulate events formed by a number of rays, assuming  40 accepted photo-electrons from  250 photons produced All parameters are defined in data cards – easy to adapt L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Some validations for CEDAR-N
Cedar-N, bar of Helium, 75 GeV/c, diaphragm 10 mm PM plane at Z = 706 mm, diaphragm at 1251 mm, quartz window at 851 mm Situation Rdiaphr sdiaphr Monochromatic pencil beam K+ 100.0 0.333 Monochromatic pencil beam p+ 103.0 0.341 Monochromatic pencil beam protons 909.0 0.314 Beam spot 10 mm s in each plane 0.330 Beam divergence 0.1 mrad in each plane 0.517 Momentum spread 1% 0.343 ‘Nominal beam’ (1%, 0.1 mrad, 10 mm) 0.524 For Hydrogen at 2.61 bar: Monochromatic pencil beam K+ 100.0 0.333 ‘Nominal beam’ (1%, 0.1 mrad, 10 mm) 0.524 L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Ring at correct position p-K separation as expected:
3 mm L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Conclude: Simulation program works well Can be used as a tool to optimise Added realistic 1/l2 spectrum Improved n(l) curves (as shown befor) Added different versions of PMT, mirrors, Absolute photon production rates L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Cedar-North Monochromatic pencil beam 75 GeV/c, Dp/p=0,sx=0, sx’=0
HELIUM Gas HYDROGEN Gas Mean=100.0 mm RMS = 0.15 mm Monochromatic pencil beam 75 GeV/c, Dp/p=0,sx=0, sx’=0 RMS = 0.78 mm Mean = 99.9 mm RMS = 0.36 mm Realistic beam (plotted), 75 GeV/c, Dp/p=1%, sX=1 cm, sX’= 80 mrad Mean = 99.5 mm RMS = 0.84 mm L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Unsuited L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Cedar-West (H2 filled) Resolution is ok! 100.0±0.48 mm 102.3±0.45 mm L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Conclude: Studies now based on H2 filled West Cedar L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

generated Cedar-North Cedar-West hitting mirror hitting mirror Z-position where g is generated [mm] Nose Nose ‘Nose’ not so useful for Cedar-West (Efficiency curve almost identical with and without nose) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Spot at ‘old’ PMT location, e.g. for PMT #1: 20 x 7 mm2 Y (mm) Y (mm) X (mm) X (mm) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Conclude: Spot on the small side Could remove nose Can increase spot with ellipsoidal mirrors Propose to modify the PM part of CEDARs L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Mirror geometry: rotated by ≈ 45 degrees Beam Diaphragm Many PMT’s Light condensor L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

With only 2 parameters (a and b) it is possible to generate a light spot with quite reasonable freedom in two dimensions. By using a different mirror, one can provide an equivalent light spot for the 2006 tests These mirrors do not need to be of extreme optical quality However, not favourable to go too far away from the beam axis, because muon halo increases rapidly with radial distance As an illustration some examples are shown. Note: for the moment, this is a simplified simulation: 1. Take simulated photon trajectories from full (corrected) Cedar simulation 2. Rotate to single condensor position on X-axis 3. Put mirror vertical (not tilted by 45o). Equivalent to first order 4. Detector therefore vertical, upstream of the mirror A final choice remains to be made L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Assume realistic beam conditions: Momentum spread 2% RMS around 75 GeV/c Spot size at CEDAR 10 cm radius (irrelevant for performance) Beam divergence 80 microradians RMS in each plane Multiple Coulomb scattering in Hydrogen according to p and P Generate photons according to: cos qc = 1 / bn(P) dN/dl = No . L . sin2qc with No = 370 eV-1 cm-1 Wavelengths ~ 1/l2 in range [2000,6000 A], hence DE = = 4.13 eV Quantum efficiency of PMT as shown on next slide Remove nose at upstream end of Cedar Track to optical system and do light collection after reflection in ellipsoidal mirrors L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Try to optimise half axes a and b to aim for 6x3 cm spot at PM PM 10 cm away from the mirror center (i.e. about 20 cm from beam axis) First try: No good! Half axes 100, 100 mm L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Very good! 100 transverse ,140 radial l[2800,4400 A] L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Does not change with wavelength range! idem, but l[2000,6000 A] L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Proposed PMT layout (note: box = 10x10 mm, sensitive over 8x8 mm) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Assumed quantum efficiency: L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

With these numbers, for 50 MHz K+ rate: 50 MHz * 23 PMT out of 8 * 6*3 = 144  8 MHz per PMT L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

For ±1 mm diaphragm aperture L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Y of seen p.e. at PM location [mm] X of seen p.e. at PM location [mm] L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

For 1.5 mm diaphragm gap, cut at Symm*Nr cells > 7: L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Conclude: Ellipsoidal mirrors would help PMT’s have to operate at 8 MHz with good efficiency and good time resolution Final geometry of mirrors to be finalised However, something can be done with standard layout as well Simulation validated in 2006 run in H6 beam However, based on Nitrogen gas, West Cedar, some problems with scintillation light (?) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

PMT Studies Alfredo Placci has done PMT rate studies at CERN. Independently studies have been done at other labs Some of the RICH studies are of course directly applicable for the CEDAR Some “ real life” tests were done by P326 with a CEDAR in the H6 beam At the time of the proposal the ‘ partly line’ was MAPMTs Later Alfredo Placci changed his preferences to small individual PMTs, because of the better rate capability and the rather high packing factor (64%) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Laser +attenuator assembly
From A.Placci: Laser +attenuator assembly L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Laser power output, without attenuation, vs frequency(TTL 5 ns pulse)

R x10mm2 Specs L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Hamamatsu R2248 Divider E1761-22 HV 1000 V Laser pulser 30 MHz
Noise(1 p.e.) average 5 mV sigma 1.5 mV Pulse height: average 20 mV, sigma 9 mV L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Hamamatsu R2248 divider E Hv 1200 V Laser pulser 20 MHz Noise(1 p.e.) 13 mV average, 5 mV sigma Pulse height 67 mV average, 31 mV sigma L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Hamamatsu R2248 Divider HV 1200 V Pulser laser 30 MHz Noise(1 p.e.) 13 mV average, 5 mV sigma Pulse height 66 mV average, 28 mV sigma L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

MAPM H6568 HV 800 V Pulse rate 10 MHz Average pulse height 23 mV Sigma 9 mV Noise(1 p.e.) 6.7 mV, sigma 2.6 mV L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

MAPM H6568 HV 900 V Pulse rate 10 MHz, Average p.h. 66 mV, sigma 23 mV noise 16 mV, sigma 7.8 mV L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

MAPM H6568 HV 1000V Left: Pulse rate 30 MHz p.h. 147 mV,sigma 45 mV Right:Pulse rate 50 MHz, p.h. 140 mV, sigma 40 mV L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

MAPM H6568 HV 1100v Left:pulse rate 30 MHz, p.h, 250 mV, sigma 71 mV Right: rate 40 mhZ, p.h. 214 mV, sigma 59 mV L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

MAPM pulse height vs laser frequency(1.5 ns width, 0.8 ns rise-time) for various HV’s: move 800 V, yellow 900V,blue 1000 V, upper 1100V L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

CEDAR test run in 2006 in H6 beam line (test coordinated by P.Cenci, presented by L. di Lella) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

The Cedar in the H6 beam line Hamamatsu R2248 Photoghraphs from Luciano Zaccarelli L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status Hamamatsu R7400U

Pressure scan: Hadron GeV in H6 (data from J.S.) intensity within ppp (rates ≤ 2 MHz) working point on the pion peak Pions Protons Kaons Data from Jens Spanggaard L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

by Luigi Di Lella L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

READOUT Studies were presented by Bj.Hallgren et al: Recent IC’s One example of CEDAR readout TELL1 as platform Price L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Either 1 or 2 Gs/s Slow control included! L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Note package size 3x3 mm L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Typical pulse of HAMAMATSU H7260
5mV/div 2ns/div L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Example of application
10 m Cables Pulse Transformator The PM current is amplified with a gain of ~1.8 kohm Bandwidth 1MHz to ~280 MHz SNR = 180 (amplifiers and resistor thermal) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Currents 5ns Signal at ADC L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Example of “accidentals”

PMT Connections Power =15W for 96 amplifiers L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Or components on both sides
8x10 m L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Block diagram of front-end electronics
FPGA L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Use LHCb TELL1 as platform
RAM 4 x 96 Mbytes FPGA IBM PC with Linux 32 x 1 Gs/s DCS 10/100 Mbits/s TTC F.Bal design L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

1 Gs/s FADC & TELL1 (using the LKr readout as reference)
x 25 faster than LKr But only 8 instead of 10 bits as LKr <20 psec? (about 6 times better than LKr CPD) Noise? Double pulse resolution 5 nsec –> simulation Pulse shape analysis Continuous recording of the detector signals Easier zero suppression than LKr (software comparator) Rejection of accidentals, pileup and baseline shifts Coincidence with all other channels Use of TELL1 gives big savings in HW and SW design Power increased compared to present TELL1 (but only 8 / crate) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

ATB-EA & Bjorn Cedar Cost Estimate for Proposal Preliminary !!! L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

Price for 32 channels 1 TELL1 with 4xGigabit Ethernet 16 1 Gs/s dual 8bit ADC 8 FPGA Cyclone2 2EPC35F PCB and other components ~12000 To be added: 1 Crate with power supplies MHz clock distribution + DAQ electronics (PC(s) with 32 Gigabit Ethernet connections) L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

256 x 850 CHF = kCHF L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

CONCLUSIONS AND OUTLOOK Basic concept exists, feasibility in principle shown Monte Carlo simulation tool exists and should be used Responsibilities to be defined (Birmingham, ???) Do we really need extra mirrors Final choice of light detectors Hydrogen safety issues should be addressed in depth, once details defined Cost estimate needs to be revised accordingly Dedicated working group??? L.G., 22 July 2008 K12 Beam Working Group – CEDAR Status

CEDAR PROJECT STATUS FROM BEAM WG

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