1. Michael Lindgren 1 Off-Axis Workshop March 13, 2003 CDF R5900 MAPMT Experiences l Outline wCDF usage wTesting wPerformance wComments l Not sure what to cover in this talk – threw in a bit of everything l Been ~ 8 years since wrote req. – I have forgotten much

2. Michael Lindgren 2 Off-Axis Workshop March 13, 2003 Usage in Calorimeter - Overview l Mechanical Structure ä Reuse existing Hadron steel ä Replace EM detector l PES Detector Elements wScint. Strips + WLS readout (PES) PPR

3. Michael Lindgren 3 Off-Axis Workshop March 13, 2003 Shower Maximum Detector Elements A position detector embedded at ~ 6 deep in the EM calorimeter measures the position of e’s and  ’s l Sub-millimeter position resolution for energies > 100 Gev l 6400 channels of 5mm strips l 416 MAPMT’s Strips Hamamatsu R5900-M16 in CDF mount

4. Michael Lindgren 4 Off-Axis Workshop March 13, 2003 Endplug Preshower l First layer of EM section read out separately wMAPMT’s are the same as used in the SMD(R5900- M16 Hamamatsu) - 72 Tubes used - High Eta - use only 8 pixels/tube w1 cm thick tiles wSame tower structure as EM(960 channels)

5. Michael Lindgren 5 Off-Axis Workshop March 13, 2003 Calorimeter Frontend Electronics (SMXR) Schematic of Calorimeter and front end readout chain SMXR ADMEM+ l Schematic of Calorimeter and and Front end electronics readout path On CAFE SMD crate - 21 MAPMT’s Read out by each crate Green is RG-174 cabling From tubes

6. Michael Lindgren 6 Off-Axis Workshop March 13, 2003 Location – PMT boxes l Common enclosure w/ Cal PMT’s wTemp. controlled wdark l Laser - One pixel pulsed per MAPMT of PES and PPR wMonitors tube gain - but only one pixel - Assumption is that tube gain will drift for all pixels - Impractical to do more than one pixel/tube in mixed system

7. Michael Lindgren 7 Off-Axis Workshop March 13, 2003 Numbers l CDF bought 470(PES) + 80(PPR) tubes wUse 416(PES) and 72(PPR) on detector w16*400 = 6400, so using 416 means we had some wasted channels l PES cost - $1115/tube- bare l Bases/mounts built by CDF wTotal cost for that + testing ~$200K wCustom mount, CNC built to align well with 16 optical fibers delivering light

8. Michael Lindgren 8 Off-Axis Workshop March 13, 2003 Testing/performance l Tubes generally received in good shape from Hamamatsu wRejected 12 tubes of 470, bulk had lost vacuum wBulk of tubes produced in 1996 - my memory is not so great - Hamamatsu tubes may be different now… l Tested wGain/QE wCross talk wLinearity wStability wDark Current

9. Michael Lindgren 9 Off-Axis Workshop March 13, 2003 MAPMT Gains - Summary l 3:1 specification max:min gain for pixels in a tube l Average gains show no systematically “hot” or “cold” pixels

10. Michael Lindgren 10 Off-Axis Workshop March 13, 2003 Quantum Efficiency - Summary l Preshower tubes show ~ 3% higher QE wProduced 2 years after Shower Max l Specification is QE > 5% l Good uniformity

11. Michael Lindgren 11 Off-Axis Workshop March 13, 2003 Cross Talk and Relative Gain Relative Gain l Plots show pixel gain on MAPMT face l 3 HV values(2 shown) l Gain shown relative to highest gain pixel in tube l Require <3:1 variation Cross Talk l Signal seen in one pixel from light on another l Each histogram “pixel” color shows % crosstalk for that pixel for light incident on one of the other 15 l Require < 5% Quite sensitive to fiber type delivering light, if there is any gap

12. Michael Lindgren 12 Off-Axis Workshop March 13, 2003 MAPMT Linearity l 505 nm LED used l Light intensity varied l Stable, Linear Monitor Tube l 400 counts= 100pC l Require <10% dev at 100pC l Tubes were quite marginal in this regard – many barely met the spec

13. Michael Lindgren 13 Off-Axis Workshop March 13, 2003 Background Light Gain Stability l Gain Stability for high and low “DC” background light l Mimics high and low eta sections of det. l Require < 5% gain shift in 24 hours l Running experience is that they are quite stable in gain over the first two years – radioactive sources show minimal shift

14. Michael Lindgren 14 Off-Axis Workshop March 13, 2003 Power Cycling Gain Stability l Require <5% gain shift when cycling HV power

15. Michael Lindgren 15 Off-Axis Workshop March 13, 2003 Gain - Summary l Correlation - Ham. Gain and UCLA l Gain spread and Abs. Value within spec.

16. Michael Lindgren 16 Off-Axis Workshop March 13, 2003 MAPMT Dark Current l Dark current provides floor for radioactive source current measurements l < 100 pA dark current makes negligible contribution to measurement error

17. Michael Lindgren 17 Off-Axis Workshop March 13, 2003 Comments l Good ¼” tubes – not the same as larger ones wLinearity in our tubes was not great l Lots of connections at rear of tube wCDF chose to make the connector at the tube - Cheap connectors  numerous single channel problems after several recablings wSoldered cables to transition boards wMight have been better (more costly also) to solder at the tube end and put a connector at the electronics l Need to control the fiber/tube face gap carefully wReflections can cause cross talk l Integration is important l Minos probably has much more current data