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53.1 GENERAL DESCRIPTION . . . . . . . . . . . . . . 53-1

53.2 SPECIFICATIONS . . . . . . . . . . . . . . . . . 53-1

53.2.1 Electrical . . . . . . . . . . . . . . . . . . 53-1

53.2.2 Measurement Technique . . . . . . . . . . . . 53-2

53.2.3 Preamplifier . . . . . . . . . . . . . . . . . 53-2

53.3 CAMAC COMMANDS . . . . . . . . . . . . . . . . . 53-2

53.4 MECHANICAL . . . . . . . . . . . . . . . . . . . 53-3

53.4.1 Single Width CAMAC module . . . . . . . . . . 53-3

53.4.2 Preamplifier . . . . . . . . . . . . . . . . . 53-4

53.4.3 Toroid . . . . . . . . . . . . . . . . . . . . 53-4

53.5 DRAWING PACKAGE NUMBER . . . . . . . . . . . . . 53-4

53.6 RESPONSIBLE ENGINEER . . . . . . . . . . . . . . 53-4 CHAPTER 53 TOROID CHARGE MONITOR (TCM)

53.1 GENERAL DESCRIPTION The TCM is designed to measure the charge passing in a single bunch. It consists of a toroid transformer, with an eight-turn secondary, the beam acting as a single turn primary. The secondary winding is connected to a preamplifier box (135-758), which contains a shunt capacitor, forming a resonant circuit at about 50 kHz. The signal from the preamplifier, consisting of a damped sine-wave, is fed to the TCM, where it is rectified, held in a sample & hold circuit, and digitized by a 10-bit ADC. The time of sampling is set by an external gate, supplied by a PDU, via the upper backplane. Calibration is carried out by means of a pulse from the CAMAC module to a single turn winding on the toroid. The level of the pulse can be set remotely by means of a DAC.

53.2 SPECIFICATIONS

53.2.1 Electrical o SENSITIVITY 1E9 - 5E10 electrons Full Scale. (Approx. 8 nanocoulomb full scale). With single bucket beam pulse(s). o ACCURACY Approx. 1% Absolute at Full Scale. Approx. 0.25% relative to Calibration Charge. o DYNAMIC RANGE 2:1 Nominal to full accuracy. 10:1 functional with reduced accuracy. ______________________________ This chapter is adapted from a memo by E. L. Cisneros dated 6/25/83 and titled "Specification for SLC Toroid Charge Monitor."


TOROID CHARGE MONITOR (TCM) Page 53-2 o TRIGGER SOURCE ECL outputs, on backplane, from a dedicated PDU. Channel 12 enable, channel 11 trigger.

53.2.2 Measurement Technique Resonant toroid with sample and hold.

53.2.3 Preamplifier External, remote, close to toroid with appropriate shielding.

53.3 CAMAC COMMANDS o F16 A0: WRITE DAC. Data on W1-W8, is latched and presented to the DAC. Calibrate Level: 0-8n Coulomb. X and Q are returned to the dataway. o F1 A0: READ DAC. Data at the input to the DAC is presented to the dataway (R1-R8). X and Q are returned to the dataway. o F0 A1: READ ADC. Data is presented to the dataway (R1-R10) After receipt of a sample and convert command, from a PDU, and conversion is complete. X is returned to the dataway. Q is returned to the dataway only when the data is valid. o F0 A0: ZEROS RETURNED TO DATAWAY (R1-R10). X and Q are returned to the dataway, for BPM compatibility, only after data is valid.


TOROID CHARGE MONITOR (TCM) Page 53-3 o F0 A2: ZEROS RETURNED TO DATAWAY (R1-R10). X and Q are returned to the dataway, for BPM compatibility, only after data is valid. o F1 A1: READ OFFSET. The offset data from offset switches is presented to the dataway (R1-R8). X and Q are returned to the dataway. o F3 A0: READ MODULE TYPE AND SERIAL NUMBER. The module serial number data is presented to the dataway (R1-R10). The module type data is presented to the dataway (R11-R16). X and Q are returned to the dataway. o F9 A0,F0 A2*Q (Data Valid), Z, Power On: CLEAR. All module functions except DAC are reset. X and Q are returned to the dataway. o F24 A0: CALIBRATE. Sets module to calibrate mode. Calibrate pulse is initiated by PDU Channel 12. This mode is cleared by F9 A0, F26 A0, or Z. Q and X are returned to the dataway. o F25 A0: SET MODULE TO PEDESTAL MODE. Pedestal function initiated by PDU Channel 12. (Equivalent to setting DAC to 0.) This mode is cleared by F9 A0, F26 A0, or Z.

53.4 MECHANICAL

53.4.1 Single Width CAMAC module Front Panel with the following items: o 4 Double-pin LEMO connectors: J2 - Input from Pre-amplifier J3 - Calibration Trigger Pulse output J5 - Output set when Toroid signal exceeds level preset by internal DIP switch (for possible Beam Containment use). J6 - +/- 15 V for Pre-amplifier power.


TOROID CHARGE MONITOR (TCM) Page 53-4 o 2 BNC connectors: J1 - Output of raw Pre-amplifier signal (1 V first positive peak corresponds to 1.6 * 10**10 electrons) J4 - Calibration DAC output level o "X" LED o 2 Circuit Breakers: S1 -15 V S2 +15 V (visible through small slots in front panel)

53.4.2 Preamplifier Separate unit with power supplied from CAMAC module.

53.4.3 Toroid o 7/8" I.D. Ceramic Vacuum Chamber with 2 3/4" O.D. Flanges. Maximum length 6". o Ferroxcube 144T500 3C8 material. o Signal winding 8 turns. o Calibrate winding 1 turn. o Isolated Faraday shield.

53.5 DRAWING PACKAGE NUMBER 135-755

53.6 RESPONSIBLE ENGINEER E. L. Cisneros


 
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