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Linac 4, Technology Choice.

BI review on Radiation development and testing. Analogue Electronics for: - L4 Grids, - L4 Scanners, - PS Complex Grids. Linac 4, Technology Choice. Initial design was for Linac 4. 21 Wire-grids at 11 positions, 6 X-Y Wire-scanners.

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Linac 4, Technology Choice.

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  1. BI review on Radiation development and testing.Analogue Electronics for:- L4 Grids,- L4 Scanners,- PS Complex Grids. Gerrit Jan Focker, BE/BI/PM

  2. Linac 4, Technology Choice. • Initial design was for Linac 4. • 21 Wire-grids at 11 positions, • 6 X-Y Wire-scanners. • At the time of designing the radiation levels were unknown, but said to be “high”. • Little time for development, production planned right from the start. • No choice was given about where to place the equipment. • To reach the specifications the electronics should be near the detectors (Initially 1m80, new design would allow ~8m), i.e. in the tunnel. • Therefore we have opted for a system with only the absolutely necessary electronics near the beamline: • Only amplifiers, • No logic, • Remote power supplies. Gerrit Jan Focker, BE/BI/PM

  3. PS Complex (excluding L4). • While designing for L4 it was decided that the system could easily be adapted to be used for integrating amplifiers for the PS Complex as well, with different amplifiers. • Standardisation. • But: as a result the decision was taken to install this new system in the whole PS Complex during LS1. • 45 Wire-Grids at 33 positions. • Very little time for development, the production started before testing with beam. Gerrit Jan Focker, BE/BI/PM

  4. Grid System overview. • Between Grid and Amplifier: two cables with twisted pairs with individualscreening. The two cables will be mounted together in large Harting 72-pin connectors. • (Twisted-pairs simply because it is available at CERN…) • At the PS Complex on many grids (existing) LEMO cables will be used. • Between Amplifiers and Controls a single cable will be used (CERN ND100) mounted with Harting 108-pin connectors. • Power and I/O control are handled by the same ND100 cables, no additional cabling is foreseen. • At Linac 4: Bias +120V directly onto measuring wires. • This talk is about the Amplifiers only. Gerrit Jan Focker, BE/BI/PM

  5. Amplifier-boxes. • Up to 32 channels per Motherboard , 2 Motherboards possible in one 2U chassis. • Daughter-boards carrying 4 amplifiers each. Gerrit Jan Focker, BE/BI/PM

  6. Amplifier Design Details. • No electronic switches: miniature reed-relays. • No radiation problems, • Galvanic isolation, • Low contact resistance, • More problems with manufacturing… • The amplifiers cannot consume too much power, • Power: losses over 200m cable. • By reducing heat in chassis we hope to increase lifetime. • Input-protection by small-signal diodes BAV199 and zener-diode(s) BZX84Cxx. • Amplifiers AD8610ARZ, AD8032ARZ and AD8397ARZ, • All from Analog Devices XFCB process, • (Not that many alternatives anyway…) • Report from the European Space Agency and NASA: • “Commercial Components Identification In Naturally Radiation Hardened Technologies” 2002ESASP.507...17M • Chips from this family that were tested were still o.k. after 100kRad(Si) radiation. • It is claimed that these chips appear not to suffer from single event upset. • But a remote control of the Power Supplies is foreseen. Gerrit Jan Focker, BE/BI/PM

  7. Linear Amplifier for Linac’s (1). • Amplifier’s Maximum Electrical Input: 10mA, • Amplifier’s highest sensitivity: 1μA full scale, • The calculated input-related noise-level is ~2nA at 1MHz BW. • Overall BW is mainly defined by the cable-length between grid and electronics, • The newer design allows cables up to 8m. • Isolated input-stage: • Bias of up to +120V on measuring wires (Linac 4). • Isolated input-stage avoids large input-capacitors. • The design includes the use of test-resistances: • At the amplifier-inputs. • Outside the vacuum-chamber at the cable-connection, • At the grid in the vacuum-chamber, • (Only applied at the new L4 grids and Scanners). Gerrit Jan Focker, BE/BI/PM

  8. Linear Amplifier for Linac’s (2) Gerrit Jan Focker, BE/BI/PM

  9. Linear Amplifier for Linac’s(3). Gerrit Jan Focker, BE/BI/PM

  10. Scanner Amplifier (L4). • For the Scanners the same linear amplifiers are used as for the Linac SEM-Grids. • Same 4-channel Amplifier boards. • Grids have many wires: • If a channel dies one will still have a picture. • Redundancy for the scanners: • Two Amplifiers are connected to each wire, • Each channel is doubled from beginning to the end and uses two ADC channels. Gerrit Jan Focker, BE/BI/PM

  11. Scanner Amplifier input. Gerrit Jan Focker, BE/BI/PM

  12. Integrating Amplifier for circular machines (1). • Amplifier’s Maximum Electrical Input: 250nC, • Amplifier’s highest sensitivity: 2,5pC full scale, • The sensitivity appears to be limited mainly due to instabilities from the Power Supply (quite variable, 25fC ???). • Cable-length between grid and electronics defines noise and speed of the Amplifiers, • Some cables up to 20m, • For reliable measurement of the short pulses at TT2: length should be < 3m. • Test-resistances: • Only at the amplifier-inputs. • Grids and cabling would have to be rebuilt for others tests. • Two input circuits: • Active integrator for charges up to 2,5nC, • Passive integrator for higher charges. • The active integrator should be able to withstand a pulse of at least 250nC ! Gerrit Jan Focker, BE/BI/PM

  13. Integrating Amplifier (2) Gerrit Jan Focker, BE/BI/PM

  14. Integrating Amplifier (3) Gerrit Jan Focker, BE/BI/PM

  15. Integrating Amplifier (4) Gerrit Jan Focker, BE/BI/PM

  16. Integrating Amplifier (5) Gerrit Jan Focker, BE/BI/PM

  17. Placement of the electronics in the tunnels. • L3, PS inflection zone , Booster BTM, LEIR, TT2 and most of the L4: • Underneath or close to the Beamlines. • Help from the Radiation-to-Electronics Team (Joao), • L4: Define a position close to the Dump for a small Rack and protection. • PS and Inflection zone, • PS position 42 to 56: use the gap next to the support girder like Jeroen does. • Inflection zone: just move some electronics out of the way. • Cable-lengths: • Linac’s linear amplifiers: up to 8m. • Integrating amplifiers (not TT2): more than 8m degrades signal. • TT2: shorter than 3m. Gerrit Jan Focker, BE/BI/PM

  18. Place in the Linac 4 tunnel (1) Gerrit Jan Focker, Jean Tassan-Viol, BE/BI/PM

  19. Place in the Linac 4 tunnel (2) Joao Pedro De Carvalho Saraiva, Jean Tassan-Viol, Gerrit Jan Focker, BE/BI/PM

  20. CPS Radiation levels Original slides from Joao Pedro De Carvalho Saraiva, EN/STI/EET

  21. CPS Radiation levels Original slides from Joao Pedro De Carvalho Saraiva, EN/STI/EET

  22. CPS Radiation levels Original slides from Joao Pedro De Carvalho Saraiva, EN/STI/EET

  23. CPS Radiation levels Original slides from Joao Pedro De Carvalho Saraiva, EN/STI/EET

  24. CPS Radiation levels Original slides from Joao Pedro De Carvalho Saraiva, EN/STI/EET

  25. Conclusions. • Little choice of chips suiting our requirements, • From the chips we found at least the family characteristics seem to allow to use them in a somewhat radioactive environment. • No radiation tests done. If done, they would always have been afterwards… • Thanks to R2E for the great job finding reasonable positions in the tunnels! Gerrit Jan Focker, BE/BI/PM

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