IceCube



IceCube

PMT HV Base Board

Engineering Requirements Document (ERD)

Version 2.2h1c (Draft)

Revisions:

Version Draft #1.0 W. Stroewe

1.1 A. Karle

1.2 A. Karle July 29, 2002

2.0 N. Kitamura August 15, 2002

2.1a N. Kitamura September 13, 200229 July 2002

2.1b N. Kitamura September 16, 2002

2.1c N. Kitamura September 25, 2002

2.2 N. Kitamura October 10, 2002

2.2a N. Kitamura October 24, 2002

2.2b N. Kitamura October 25, 2002

2.2c N. Kitamura November 15, 2002

2.2d N. Kitamura November 18, 2002

2.2e N. Kitamura November 21, 2002

2.2f N. Kitamura December 12, 2002

2.2g N. Kitamura December 16, 2002

2.2h N. Kitamura January 13, 200329 July 2002

Action Items:

Action items are noted in italic in the text. The most important once are:

Fixed first dynode HV fixed for all PMT?

Power requirement

DC and pulsed currents

Discuss differences to J. Przybylski’s requirements page.

Others:

Connectors

Anode signal analog interface

7.) Noise

PRELIMINARYDRAFT

Table of Contents

Table of Contents 2

List of Figures 3

List of Tables 3

1 GENERAL 4

1.1 Scope 4

1.2 Purpose 4

1.3 Precedence 4

1.4 Responsibilities 4

1.5 Records 4

1.6 Units 4

1.7 Glossary and Acronyms List 4

1.8 References 6

2 FUNCTIONAL OVERVIEW 6

3 PERFORMANCE REQUIREMENTS 9

3.1 The HV PMT Supply 9

3.1.1 General 9

3.1.2 Dynode Chain Voltage Distribution 9

3.1.3 Damping Resistor Requirements 10

3.1.4 HV Control 10

3.1.5 Anode Current Sourcing Capability 11

3.1.6 Stability 11

3.1.7 Noise 11

3.2 Electrical 12

3.2.1 Power 12

3.2.2 Ground 12

3.2.3 Anode Signal Connection Requirements 13

3.2.4 PMT Mounting Holes Requirements 16

3.2.5 Digital Functionality Requirements 18

3.3 Physical 21

3.3.1 Definition 21

3.3.2 Overall size and shape requirements 21

3.3.3 Component placement 22

3.3.4 Excluded area 22

3.3.5 Minimum trace spacing requirements 22

3.3.6 Manual soldering compatibility 22

3.4 Environmental 23

3.4.1 Temperature Range 23

3.4.2 Pressure Range 23

3.5 Miscellaneous 23

3.5.1 Conformal coating 23

3.5.2 Silkscreen 23

Appendix 1 Design Notes 27

TABLE OF CONTENTS

List of Figures

Figure 2.1 Functional overview of the PMT HV Base board. 7

Figure 3.1 Split ground configuration requirement 13

Figure 3.2 Anode signal coupling transformer signal definition (Illustration purpose only. See text for correct winding requirements). 14

Figure 3.3 Plated-thru PMT mounting hole locations viewed from the top-side of the PMT HV Base circuit board. The numerical labels associated with the holes mark the corresponding PMT pin number whose signal assignments are defined in Table 3.3. 16

Figure 3.4 Solder pad specification 17

Figure 3.5 Ribbon connector signal assignment 20

Figure 3.7 PSL Drawing No. 5549B020. PMT HV Base Board dimensional and component placement requirements. The figure identifies suggested locations for the ribbon cable connector, the coaxial cable attachment, and the clean ground wire attachment. The PCB material thickness is for reference only. (5549020B_e.pdf) 25

Figure 3.8 PSL Drawing No. 5549C021. PMT HV Base Board component envelope definition. (5549021C_e.pdf) 26

List of Tables

Table 2.1 Summary of electrical connections requirements 8

Table 3.1 Dynode chain voltage distribution (“Dyn” denotes the n-th dynode or Dynode n. “Fn” denotes the n-th focusing electrode.) 10

Table 3.3 PMT Pin Assignment 18

Table 3.4 Power ON/OFF signal assignment 20

Table 3.6 Ribbon connector signal assignment 21

GENERAL

1

2

3 To be supplied once this document has settled down.

4 Note on functional requirements:

5 The standard operating noise level is 500 PE/sec. During lab operationg conditions at room temperature the noise level is typically 5000 Hz, initially significantly higher Therefore, we define a lab operating mode with a noise rate of up to 20kHz. For the operating mode under dark and cold conditions we assume a noise rate of 1000 Hz. The default gain will be 1E7. Gains up to 5E7 shall be supported. The default noise 500 Hz. Noise rates up to 1000 Hz shall be supported for the dark mode. Current requirements are calculated based on the above numbers for contingency in gain added.

6 Requirements refer to dark mode, unless specified otherwise.

7

8 1.0 ScopeSCOPE

This IceCube Engineering Requirements Document (ERD) specifies the physical, functional and performance requirements for the PMT High Voltage Base circuit board.

2.0 GENERAL

1 2.1 PurposePurpose.

This requirement documentation shall be applicable to the development, prototyping, testing, and verification of the PMT High-Voltage Base circuit board.

2 2.2 Precedence

. In the event of a conflict between the provisions of this document and any prior other IceCube documents above it, the provisions of this document shall govern. Conflicts with other documents are resolved by the Change Control Board.

3 2.3 Authority. Approval of this document for initial release and subsequent changes are authorized only by the Change Control BoardResponsibilities

1.4.1 Physics/Engineering is responsible for writing and updating these requirements to ensure they are correct, complete and current.

1.4.2 Quality Assurance is responsible for ensuring this document and changes to it are properly reviewed, approved and maintained.

4 Records

Records of initial review, approval and changes (Engineering Change Notices, ECN’s) in design shall be maintained according to the established processes.

5 2.4 Units.

Weights and measures in this document are expressed in the MKS International System of Units (SI).

6 2.5 Glossary and Acronyms List.

ADC Analog-to-Digital Converter

AWG American Wire Gauge

cm Ccentimeter

CMOS Complementary Metal Oxide Semiconductor

CS0 Chip-select bit 1

CS1 Chip-select bit 0

DAC Ddigital-to-Aanalog Cconverter

DAQ Data Acquisition System

DC Ddirect Ccurrent

DOM Ddigital Ooptical Mmodule

DOMMB Digital Optical Module Main Board

ERD Engineering Requirements Document

G Giga (109)

HV Hhigh Vvoltage

Hz Hhertz

ID Inside Diameter

IID In-Ice Devices

IDC Insulation Displacement Connector

IPC Institute for Interconnecting and Packaging Electronic Circuits

k Kkilo (103)

kg Kkilogram

LED Light-Emitting Diode

MKS Mmeter-kilogram-second

M Mmega (106)

m Mmeter

mA Milliampere

MOSI Master-Out-Slave-In

MISO Master-In-Slave-Out

mVv Mmillivolt

mW Mmilliwatt

n Nnano (10-9)

Nt newtonOD Outside Diameter

OM Optical Module

P Peta (1015)

Pa Ppascal

PCA printed circuit assembly

PCB Pprinted Circuit Board

PE Pphoto-electron

pF Pico Farad

PMT Pphotomultiplier Tube

P/N Part Number

PSL Physical Sciences Laboratory, University of Wisconsin-Madison

P/V ratio Peak-to-valley ratio

s, sec Ssecond

SCLK Serial Clock

SI Système International d’Unités

SMB Sub-Miniature B

SPE Ssingle Photoelectron

T Tera (1012)

TBD To Be Determined

TBS To Be Supplied

UL Underwriters Laboratory

V Vvolt

VDC Volt DC

W Wwatt

1 References

• IceCube DOM Main Board – PMT HV Base Board Interface Requirements (Document No. 9000-0006)

• DOM Main Board Hardware Requirements (Document No. 9000-0007)

• PSL Drawing No. 5549B020 (PMT HV Base Circuit Board)

• PSL Drawing No. 5549C021 (PMT Envelope)

• IPC-2221 (Generic Standard on Printed Board Design)

FUNCTIONAL OVERVIEW

in terms ofThe photo-multiplier tube high-voltage base (PMT HV Base) board is a modular PCB component to be integrated into each of the approximately 5000 optical modules (OM), containing a photo-multiplier tube (PMT), that will be deployed in the Antarctic deep-ice (below several kilometers) for scientific research purposes. The PMT referred to in this document is a Hamamatsu Model 7081-02 with a nominal size of 10 inches (25.4 cm) in diameter and a nominal gain of 108.

The PMT HV Base board is required to function continuously without service over the entire twenty-year span of the research project under the deep-ice condition. The operating temperature of the PMT HV Base board is a function of the deployment depth of the Optical Module in the ice, ranging roughly from –20(C to –40(C, whereas the operating pressure is that of the internal pressure of the OM, approximating the Antarctic ambient pressure of ~0.5 atm. See 3.4 Environmental.

The PMT HV Base board has physical and electrical connections inside the OM with the photo-multiplier tube (PMT) and the digital optical module (DOM) main board (MB), the latter serving as the master controller of the entire OM. Figure 2.1 depicts the functional relationship among the PMT HV Base board, the DOMMB and the PMT. Table 2.1 summarizes the electrical connections between the PMT HV Base Board and the DOM Main Board.

The purpose of the PMT HV Base board is to facilitate the following functions:

1. Generate a series of high-voltages for the individual dynodes, focusing electrodes and the anode of the PMT, using the power provided by the DOMMB.

2. Transfer the anode signal pulses from the PMT to the DOMMB without distortion through a coaxial cable.

3. Respond to the digital control commands issued by the DOMMB for power on/off and for the adjustment of the high voltages.

4. Provide a digital reading of the high voltage to the DOMMB upon request.

5. Provide digital board identification information to the DOM MB upon request.

The mechanical installation of the PMT HV Base board is accomplished by inserting the PMT lead pins into the plated-thru holes arranged on the PCB and soldering the pins to the annular pad associated with each plated-thru hole; this procedure also establishes the electrical connections between the PMT and the PMT HV Base board.

Detailed functional and performance requirements are specified in the rest of the document.

[pic][pic]

3.1 Function. The PMT HV Base circuit board is a custom-designed commercial product with a low power consumption of less than 300 mW. It will be used to provide the HV for the 10 inch PMT R7081-20 manufactured by Hamamatsu.

3.2 Installation. The PMT HV Base circuit board is mounted to the leads at the end of the PMT. The PMT Anode signal cable provides a signal link between the PMT HV Base Circuit Board and the DOM PCB. A separate cable between the PMT HV Base Circuit Board and the DOM PCB provides the DC voltage. The DOM PCB shall transmit control signals and receive monitoring signals from the PMT HV Base. The PMT HV control and monitor signals shall be digital to prevent noise; correspondingly, the interface and PMT design shall demonstrate that no noise is introduced by the operation of the PMT HV base.

Figure 2.13.1 Functional overview of the PMT HV Base board.

Table 2.1 Summary of electrical connections requirements

|Connection method |Explanation |Section |

|Plated-thru mounting holes |The board is physically mounted to the PMT by soldering the|3.2.4 |

| |pins to these holes, which also makes electrical | |

| |connections. | |

|Coaxial |Connection between the secondary of the anode signal |3.2.3 |

|RG-180B/U or equivalent |coupling transformer and the DOM main board. The board | |

| |shall be delivered with one end of the coaxial cable | |

| |attached to it. The other end of the coaxial cable | |

| |requires an SMB type connector. | |

|IDC Ribbon cable |Digital signals |3.2.5.2 |

| |DC power | |

| |Power & digital ground | |

| |A female connector is required on board. | |

|0.52 mm2 (20 AWG) stranded wire |“Clean ground” connection. |3.2.2.1.E |

| |The board shall provide a wire pad. | |

3.3 Function and Performance.PERFORMANCE REQUIREMENTS

1

2 The HV PMT Supply

1 General

This subsection specifies electrical requirements applicable to the HV PMT supply portion of the PMT HV Base Board 4.2 .

1 Note on requirements alternatives

A set of alternative requirements, replacing the requirements defined in Section 3.1.4, shall be issued at a later date as a supplement to this ERD. The vendor of the PMT HV Base board shall be appropriately notified by IceCube as to whether the present requirements or the said alternative requirements are to be enforced.

2 3.3.1 HV Generation.

The method of HV generation shall be compatible with all theother performance requirements stated in this e rest of the document. In particular, the electrical impedance of the voltage sources for the individual dynodes A Cockroft-Walton type circuit topology may be used, in which case thestclose to. must be sufficiently low in order to meet the anode current sourcing capability (3.1.5).[i]

3 Definition

a) “First dynode voltage” shall refer to the voltage between the cathode and the first dynode of the PMT.

b) “Anode voltage” shall refer to the voltage between the first dynode and the anode of the PMT.

4.1.6

2 Dynode Cchain Vvoltage Ddistribution[ii]

1 Cathode potential

The PMT cathode shall be at ground potential.

2 Dynodes

The dynode chain voltage distribution (voltage ratio) shall be (TBD).The voltage across the successive dynode stages shall be according to the values specified in

Table 3.1 in which the values are expressed in terms of a factor to be multiplied by the voltage across Dynode 1 (first dynode) and Dynode 2.

3 Focusing electrodes

The voltage for the focusing electrodes, denoted as F1 – F3, shall also be determined by the factor specified in

Table 3.1 multiplied by the voltage across Dynode 1 and Dynode 2.

Note: F1 and Dy1 are at the same potential. F2 and F3 are at the same potential.

3 Damping Resistor Requirements

1

A 100Ω (5% or better) resistor shall be present between each one of the last dynodes (Dy8, Dy9 and Dy10) and the corresponding high-voltage sources.

2

The said damping resistors shall be installed at locations easily accessible for the IceCube engineers to shunt or replace after the PMT HV Base board has been mounted on the PMT.

Table 3.1 Dynode chain voltage distribution (“Dyn” denotes the n-th dynode or Dynode n. “Fn” denotes the n-th focusing electrode.)

|Interval |Voltage relative to Dy1 - Dy2 |

|Dy2 - Dy3 |1.25 |

|Dy3 - Dy4 |0.83 |

|Dy4 - Dy5 |0.42 |

|Dy5 - Dy6 |0.25 |

|Dy6 - Dy7 |0.30 |

|Dy7 - Dy8 |0.38 |

|Dy8 - Dy9 |0.55 |

|Dy9 - Dy10 |0.75 |

|Dy1 - F1 |0.15 |

|Dy1 - F2 |0 |

|Dy1 - F3 |0.15 |

4

5 Justification: This depends on the final selection of the PMT model.

6 HV Control

1 Justification: Cockcroft Walton type voltage multipliers provide a power efficient way of HV generation for PMT.

2

3 HV controllability requirements

1 First dynode voltage

a) The PMT HV Base board shall allow the first dynode voltage shallto be set to the factory default value of 700 VDC.a

b) There shall be a provision for changing the said factory default value after delivery by the IceCube personnel to a value in the range of fixed value in the range of 6400 to 8600 VDC after delivery, using a readily-accessible and reliable method, such as installing or replacingpreferably by installing a resistor of a suitable value.

2 Cathode-to-anode voltage

The cathode-to-anode voltage shall be adjustable at least over the range of 1000 to 2000 VDC (TBD) by means of a means of a suitable digital code written written to thea DAC residing on the PMT HV Base boardby the DOM main board.[iii]usually chosen to be 29%, . ais The digitally adjustable voltage ranges are (TBD).

4 HV monitoring requirement

There shall be a provision for monitoring the cathode-to-anode voltage as a digital code of an ADC reading transmitted to the DOM main board.[iv]

5

6 Digital interface

1 DAC resolution

The DAC used for setting the HV shall have a resolution of 12-bit.

2 ADC resolution

The ADC used for monitoring the HV shall have resolution of 12-bit.

3 Digital code vs HV[v]

a) The digital code for setting and monitoring the HV shall be in 12-bit unsigned straight binary with the digital value 000(hex) representing 0 V.

b) The digital value and the corresponding HV value shall have a linear relationship at least in the voltage range specified in 3.1.4.1 with the slope of 0.5 V per bit.

7 Anode Current Ssourcing Ccapability[vi]

The HV generator of the PMT HV Base board shall support the following current sourcing capability in the sense that the output voltage does not drop more than 10 V while producing the specified current::

a) DC anode current of 12 nA at –40 (C (deep-ice).

b) DC anode current of 240 nA at room temperature (laboratory).

c) Square-pulse anode current of 100 mA lasting for 1 μsec.

Square-panode

8 Stability

The drift rate for the voltages supplied to the dynodes and the anode shall be less than 4 V / week during the regular in-ice operation.[vii]

9 Noise

The ripple voltage observed at the output of the secondary of the anode signal-coupling transformer shall be no greater than 0.5mVpp when the output is terminated with a 100 Ω resistor.[viii]

3 Electrical

1 Power

1

Voltages between the cathode and the first dynode are to be set separately.

Voltages between the cathode and the first dynode are to be permanently, e.g. by choice of a resistor. These voltages range from 400 to 660 VDC. Voltages between the first dynode and the anode are to be set separately by serial communication to a DAC. These voltages can range from 300 VDC to 1320 VDC. The HV can be turned down or turned off completely by the DOM PCB.

Justification: The PMT gain is controlled by the voltage across the dynode chain (first dynode to anode). The first dynode voltage is frozen to a predetermined value. The first dynode voltage is mainly needed to warrant an adequate P/V ratio. This parameter should not require readjustment.

Status: 20 prototypes are expected in August for tests. A total of 20 PMT are available to perform tests.

Drawbacks: Approach is somewhat unconventional. Some questions are not answered yet. Can the first dynode voltage be uniform for all PMT? Would we need a unique base (resistor setting for first dynode) for every PMT?

Alternate requirement definitions:

Variable control via DAC of the voltage between the first dynode and the anode. Variable control via DAC between the cathode and the first dynode.

Justification: This design allows maximum flexibility. The P/V can be adjusted and readjusted if needed or desired. The PMT gain is controlled separately by the voltage across the dynode chain. The first dynode voltage mainly influences the P/V ratio of the PMT but only to lesser degree the gain. No final decision on the first dynode voltage is needed.

Status: Such a design is has been used on string 18 and on the about 20 DAOM deployed in AMANDA-II.

Variable control between the cathode and the anode (classical design).

Justification: As long as the P/V ratio is within the requirements it doesn’t matter if the P/V ratio changes as a function of HV. This is a conventional mode of operation.

Status: This is probably the simplest design.

Drawbacks: However, if a PMT which is rated for a gain of 1E8 is operated at a gain of 1E7, it is likely that the P/V ratios drop to values that are unnecessary small.

3.3.3 HV stability. Any fixed HV setting shall not vary by more than 0.2%/week during regular operation. Any variable HV setting shall not vary by more than 4V/week during regular operation.

Jusitification: The gain-HV relation of the PMT in consideration can be approximated by G = A VB. Therefore a gain stability of dG/G=x requires a voltage stability of dV/V = (B-1)*dG/G. In our case, B is in the range from 8 to 10, depending on the tube. We assume B=10, the worst case. Then a 2% change in gain will arise from a 0.2% change in voltage. Likewise, 3% gain setting ability will be gotten with 0.3% voltage change.

Noise. Maximum ripple induced by the HV generator onto the anode signal shall not exceed 0.25 mVp-p.when terminated with 100 Ohm.

Justification: Difficult.

0.25 mV will be not easy to measure.

Alternate requirement:

Noise shall be small enough that the P/V ratio of the PMT is not reduced by more than 5%, when operated at a gain of 1E7.

DAC resolution. The DAC resolution shall be 12 bit.

Justification: A resolution and 2% of the gain appears adequate. In order to avoid fluctuations due to quantization jumps it the DAC resolut6ion should be small compared to the required stability.

An 12 bit resolution meets this requirement.

Monitoring voltage: A monitoring signal of the actual HV shall be provided using a 12 bit ADC to readout the actual HV.

Justification: It is useful to read the exact state of the HV. The ADC resolution should meet the DAC resolution.

Resolution. The maximum linear output of the PMT converts to a nominal digital value of 7168.

Justification: Don’t know. Drop this?

Current range: A DC anode current of 12 nA shall be supported. Under lab operating conditions an increased anode current of 240 nA is required.

Justification: In standard operating mode the ADC current will be less than 12 nA. Explanation: This allows operation of the PMT at a single photoelectron rate of 20.000 Hz. It corresponds to a laboratory operating requirement at room temperature. The following assumptions were made for this estimate:

Max gain: 5e7

Max noise: 20 kHz/1 kHz (lab mode/dark mode)

Assume 1.5 PE/pulse.

This results in the

Maximal anode currents in lab mode: 240 nA

Maximum anode current in dark mode: 12 nA

Power and noise requirements may be specified separately for lab mode and dark mode.

Pulses: Anode pulses of up to 100 mA (0.1A) shall be supported for the duration of 1 µsec while in standard operating mode.

Justification: An anode current of as much as 100 mA is provided by the PMT. It is required to allow for the dynamic range system requirement. If the base supports currents of up to 1 µsec it will also support all pulses that are realistically possible in the ice.

3.4 Physical Properties.

3.4.1 Circuit Board Size. The overall circuit board design shall be circular and no larger than xxx mm diameter. A wider diameter or a deviation from the circular design for accommodation of special components such as connectors or interfaces may be applied if no components on the outer edges interfere with the pressure vessel. Detailed drawings defining the geometric dimensions of the base are given in appendix 1.

Justification: The PMT and the base need to fit inside the sphere. See drawings.

Need input from PSL, Dan Wahl’s drawings

3.4.2 Circuit Board Layout. The circuit board layout shall conform to IPC Specification # ____________ appropriate for the voltage(s) and potential(s) being routed and for extreme temperature (+40° C to -40° C) operation.

Do we need to ask for –70 C -( IceTop requirements? Ask Paul Evenson, Bartol?

3.4.3 Assembled Circuit Board. The assembled circuit board may have components on both sides. Components facing the PMT shall be no taller than x cm. Components facing the pressure vessel shall be no taller than y cm. Assembly of the circuit board shall be done in accordance with IPC Specification # ___________________ .

Alternate requirement:

3.5 Interfaces.

The PMT HV Base circuit board shall receive the electrical power from the DOM Mmain Bboard through the ribbon cable connector specified in 3.2.5.2.

2

The power source available to the PMT HV Base circuit board shall be a ±5 VDC voltage source with a voltage uncertainty of ±5%.

3

The maximum power dissipation of the PMT HV Base board shall be 300 mW.

2 Ground

1 Split ground configuration

1 Definitions

The PMT HV Base board shall have two isolated ground planes as defined below (See Figure 3.1):

a) Digital and power ground shall be referenced by the incoming power from the DOM Mmain Board; the digital control and monitor circuitry including the ADC and the DAC; and, the regulator and switching circuitry for HV generation.

b) Clean analog ground shall be referenced by the voltage multiplier, dynode resistive divider, and regulator feedback circuitry.

2 Isolation resistance

The two ground planes defined above shall have a minimum isolation resistance of 10 MΩ.

3 Stray capacitance

The stray capacitance between the two ground planes shall be less than 50 pF.

4 Jumper requirement

The PMT HV Base board shall have solder pads for a solderable jumper (a zero-ohm resistor) between the two ground planes.

a) .The installation of the jumper is optional and shall be decided by the IceCube engineers after the delivery.[ix]

b) The PMT HV Base board shall delivered without the jumper installed.

5 Wire soldering pad requirement

The PMT HV Base Board shall have a wire soldering pad for the purpose of attaching a 20 AWG (0.52 mm2 conductor area) stranded wire for the “clean analog ground” connection to the DOM Main Board.

[pic]

Figure 3.1 Split ground configuration requirement

3 Power ON/OFF control

The PMT HV Base board shall support a power ON/OFF control by the DOM main board through the ribbon cable (4.2.7.4).

4 Digital board identification

5 The PMT HV Base board shall provide a unique digital board identification number (board ID) upon request from the DOM main board. The board ID shall be sent to the DOM main board by serial communication via the ribbon cable when the device IDENT is selected (See 4.3, Table 4.4).Anode Signal Connection Requirements

1 Signal coupling method

The PMT HV Base board shall employ a coaxial toroidal transformer in order to deliver the PMT signal pulses to the DOM main board.

1 Transformer signal definition

The transformer shall consist of a coaxial cable wound around a toroidal magnetic core.

a) The center conductor and the shielding conductor of the coaxial winding shall provide the primary winding and the secondary winding of the transformer, respectively.

b) The primary conductor and the secondary conductor accessible at one end of the coaxial winding shall be designated as the “dotted side” of the terminals (See Figure 3.2).

2 Transformer specification

a) The transformer shall consist of a coaxial cable wound nineteen (19) times around a toroidal magnetic core.

b) The said coaxial cable shall be RG-178/U or RG-178B/U with a Teflon inner dielectric and a Teflon outer jacket.

c) The said toroidal magnetic core shall be Magnetics Model ZH-42206-TC (mag-) or equivalent.

d) Adequate spacing between the windings shall be provided in order to insure high-voltage isolation integrity.

e) There shall be an adequate means to hold the windings in place (such as a plastic plug pressed into the toroidal center, or a “belly-band” around the transformer).

3 Primary side requirements[x]

a) The primary side of the coaxial transformer shall be terminated with a 100Ω resister across the primary terminals (“back termination”).

b) The “dotted” side of the primary terminal shall connect to the PMT anode terminal.

c) The “un-dotted” side of the primary terminal shall connect to the source of the anode high-voltage.

4 Secondary side requirements[xi]

a) The secondary side of the coaxial transformer shall be connected to the DOM Main Board using a coaxial medium.

b) The said coaxial medium shall be RG-180B/U or a similar coaxial cable with a characteristic impedance of 100Ω.

c) The center conductor and the shield conductor of the said coaxial cable shall connect to the “dotted” side and the “un-dotted” side of the secondary terminal of the transformer, respectively.

[pic]

Figure 3.2 Anode signal coupling transformer signal definition (Illustration purpose only. See text for correct winding requirements).

[pic]

5 Coaxial cable installation requirement

6

The PMT HV Base Board shall be delivered with the coaxial cable specified in 3.2.3.1.D installed.

a) Electrical connections of the coaxial cable shall be accomplished by direct soldering.[xii]

b) The said electrical connections shall not degrade when the cable is pulled with a maximum of 5kg of force in any directions.

c) The length of the coaxial cable shall be 20 (1cm.

d) The end of the said coaxial cable not attached to the PCB shall have a right-angle, crimp-type SMB connector.

e) The said SMB connector shall be AEP 2715-1521-004, gold plated coax crimp type; or, Sealectro 51-128-9511[xiii].

Overview

|Electrical connections |The board is physically mounted to the PMT by |

|requirements are summarized in |soldering the pins to these holes, which also makes |

|4.1. The detailed |electrical connections. |

|specifications are given in the | |

|subsequent sections to | |

|follow.4.1 Summary of | |

|eConnection methodPlated-thru | |

|mounting holes | |

6 PMT Mounting Holes Requirements

1 Plated-thru PMT mounting holes and soldering pads

1

The PMT HV Base board shall have plated-thru holes specified in Figure 3.3 in order to make electrical connections to the PMT.

2

Each of the said plated-thru holes shall have an annular soldering pad in the manner specified in Figure 3.4.

3

The locations of the said plated-thru holes on the PCB are as specified in Figure 3.7.

2 Signal assignment to the PMT mounting holes[xiv]

1

The electrical signal assignment to the plated-thru PMT mounting holes are as shown in Figure 3.3 and Table 3.3.

2

The PMT HV

Connectors.

PMT. Base board shall not be required to have holes to accommodate the pins that are assigned “No connection”.

given here

[pic]

Figure 3.3 Plated-thru PMT mounting hole locations viewed from the top-side of the PMT HV Base circuit board. The numerical labels associated with the holes mark the corresponding PMT pin number whose signal assignments are defined in Table 3.3.

[pic]

Figure 3.4 Solder pad specification

Table 3.3 PMT Pin Assignment

|Pin # |Signal name |Description |

|01 |NC |No connection |

|02 |Dy1 |Dynode #1 |

|03 |F3 |Focus #3 |

|04 |NC |No connection |

|05 |Dy3 |Dynode #3 |

|06 |NC |No connection |

|07 |Dy5 |Dynode #5 |

|08 |Dy7 |Dynode #7 |

|09 |Dy9 |Dynode #9 |

|10 |P |Anode |

|11 |NC |No connection |

|12 |NC |No connection |

|13 |NC |No connection |

|14 |Dy10 |Dynode #10 |

|15 |Dy8 |Dynode #8 |

|16 |Dy6 |Dynode #6 |

|17 |Dy4 |Dynode #4 |

|18 |NC |No connection |

|19 |Dy2 |Dynode #2 |

|20 |F1 |Focus #1 |

|21 |F2 |Focus #2 |

|22 |NC |No connection |

|23 |NC |No connection |

|24 |K |Cathode |

7 Digital Functionality Requirements

1 Digital signal standard

1 The digital signals (logic levels and voltages) between the PMT HV Base board and the DOM main board shall comply with the 3V CMOS signal standard.

2 The PMT HV Base Board shall not rely on the 5V-tolerance of the DOM Main Board when transmitting a signal.

2 The ribbon cable

The PMT HV Base Board shall have electrical connections with the DOM Main Board through a ribbon cable, defined in this section, for the following purposes:

• Power and ground connections

• Digital signal connections

1 The ribbon cable type

The ribbon cable shall be a 1.27mm-pitch flat IDC ribbon cable.

2 The ribbon connector type[xv]

The PMT HV Base board shall have a 2.54mm-pitch female IDC-type connector for the ribbon cable at the location specified in Figure 3.8.

The said connector shall be an AMP Micro-MaTch top-entry receptacle with locking (Tyco Electronics P/N 2-338068-0).

3 Signal duplication requirement

Each signal, ground and power in the ribbon cable shall have two connector pins allocated to it.

4 Ribbon connector signal assignment

The signal assignment to the ribbon connector pins shall be as defined in Table 3.6.

4 Chip-select (CS0, CS1)

The two chip-select signals, CS0 and CS1, shall be used in combination to select one of the following three digital devices residing on the PMT HV Base board:

• DAC: Digital-to-analog converter

• ADC: Analog-to-digital converter

• IDENT: Board identification device (3.2.5.6)

1 The assignment of the logic levels to CS0 and CS1 shall be determined by the vendor of the PMT HV Base board.

5 MOSI, MISO and SCLK signals

• DAC shall use MOSI and SCLK for data and serial clock, respectively.

• ADC shall use MISO and SCLK for data and serial clock, respectively.

• IDENT shall use one or more of MOSI, MISO and SCLK.

6 Power ON/OFF Control

1

The PMT HV Base board shall support a power ON/OFF control by the DOM Main Board through the ribbon cable.

2 ON/OFF control signal

The signal assignment for the power ON/OFF control shall be as shown in Table 3.4.

3 Power-up default

When the PMT HV Base board is turned on, the HV output shall be consistent with the DAC digital code of 0x000 (See 3.1.4.3.A).

Table 3.4 Power ON/OFF signal assignment

|Logic Level |Meaning |

|0 |OFF |

|1 |ON |

7 Digital Board Identification

1

The PMT HV Base board shall provide a unique digital board identification number (board ID) upon request from the DOM main board.

2

The said digital board ID device shall comply with the Dallas 1-Wire protocol to communicate with DOMMB serving as the bus master.[xvi]

anode signal coupling (4.2.6)main .The connection of the coaxial cable specified in 4.2.7.3.3 to the secondary side of the anode signal coupling transformer shall be made on the PMT HV Base board by soldering. The length and other requirements for the said coaxial cable shall be specified in a separate document.

The document referred to is the same one mentioned in 4.2.6. Direct soldering is more preferable than using a connector for reliability and cost reasons..The polarity of the anode signal connection shall be such that the “dot” end of the output transformer primary connects to the anode of the PMT and the “dot” end of the secondary connects to the center conductor of the coax carrying the signal to the DOM main board. See Figure 4.5.

[pic]

Figure 3.5 Ribbon connector signal assignment

[pic]

4.6

4.3 Signals. Control and readout via synchronous serial port. The PMT HV Base circuit board interfaces with the DOM PCB via a __________ connector. The cable used is flat ribbon, 14 pin, twisted pairs.

Table 3.6 Ribbon connector signal assignment

|Pin # |Signal Nname |Description |

|01 |DGND |Digital and power ground |

|02 |SCLK |Serial clock |

|03 |SCLK | |

|04 |MOSI |Master-out-slave-in |

|05 |MOSI | |

|06 |MISO |Master-in-slave-out |

|07 |MISO | |

|08 |DGND | |

|09 |CS0 |Chip-select bit 0 (See ) |

|10 |CS0 | |

|11 |CS1 |Chip-select bit1 (See ) |

|12 |CS1 | |

|13 |ON/OFF |Board enable/disable |

|14 |ON/OFF | |

|15 |+5V |Main power (+) |

|16 |+5V | |

|17 |DGND | |

|18 |DGND | |

|19 |-5V |Main power (-) |

|20 |-5V | |

What are the implications of MIL-SPEC

Power. The PMT HV Base circuit board receives its power via a separate cable, connected to a ____________ connector.

The following signals are defined:

|Pin # |Signal name |Description |

|01 | | |

|02 | | |

|03 | | |

|04 | | |

4.3 Signals. Control and readout via synchronous serial port. The PMT HV Base circuit board interfaces with the DOM PCB via a __________ connector. The cable used is flat ribbon, 14 pin, twisted pairs.

Table 4.4 Chip-select address definition

The following signals are defined:

4 Physical

1 Definition

The “bottom side” of the PMT HV Base board shall refer to the side of the PCB from which the PMT leads are inserted. The “top side” of the PMT HV Base board shall refer to the side opposite to the bottom side. The terms “top view” and “bottom view” shall refer to the views from the top side and the bottom side of the PMT HV Base board, respectively.

Note: The “ice top view” is a view of the Optical Module components in ice seen from the ice top. For the purpose of the PMT HV Base board, the “ice top view” and the “top view” are synonymous.[xvii]

2 Overall size and shape requirements[xviii]

The overall shape of the printed circuit board of the PMT HV Base shall be circular and no larger than 100 mm in diameter. A greater diameter or a deviation from the circular outline for accommodation of special components such as connectors and cable harnesses shall be permitted provided that there is sufficient clearance between such components and the interior surface of the pressure vessel of the optical module. The dimensional requirements are summarized in Figure 3.7 and Figure 3.8. The volume constraints shall apply to both of the mating pieces of the ribbon connectors.

3 Component placement

The components may be placed on either the top side or the bottom side of the PCB within the constraints of the component envelope, except for the following items, whose locations are specified in Figure 3.8:

a) Anode signal coupling transformer (Bottom side)

b) Coaxial cable for the anode signal connection

c) Ribbon cable connector (Bottom side.)

d) “Clean ground” connection wire pad

The following items shall be installed at locations where IceCube engineers can easily access for modification after the PMT HV Base board has been mounted on the PMT:

e) Components for adjusting the first dynode voltage (3.1.4.1.A)

f) Damping resistors (3.1.3)

g) Solder pads for the optional jumper (3.2.2.1.D)

Status: The figure being referred to is preliminary and incomplete.

4 Excluded area

No components shall be mounted in the areas so specified in Figure 3.8.

5 Minimum trace spacing requirements[xix]

In compliance with the circuit board trace layout rules specified for “B-4 External Conductors with Permanent Polymer Coating” in IPC-2221, §6.3 Electrical Clearance, the following conditions shall be met for both DC voltages and AC peak voltages:

• For voltage difference greater than 100 V and less than 300 V, the minimum trace spacing shall be 0.4 mm.

• For voltage difference greater than 300 V and less than 500 V, the minimum trace spacing shall be 0.8 mm.

• For voltage difference greater than 500 V, the minimum trace spacing shall be 0.8 mm plus 0.00305 mm per every volt exceeding 500 V.

6 Manual soldering compatibility[xx]

The PCB shall be compatible with the increased temperature during the manual soldering of the PMT pins at the solder pads specified in 3.2.4.

5 Environmental

3.5.2 Electrical.

3.5.2.1 Power. Power is supplied to the PMT HV Base circuit board via a separate cable. At the PMT HV Base circuit board connector, the power source shall be ±5 VDC ±5% with a source impedance of less than _____ ohms.

Need the source impedance, or just specify the current available.

The average PMT HV Base circuit board power dissipation in any operating mode shall not exceed 400 mW.

3.6 Environmental.

1 3.6.1 Temperature Range[xxi]

1 Operation

The continuous operating temperature of the PMT HV Base board shall be in the range of –40°C to +27°C.

2 Storage

The storage temperature for the. The PMT HV Base circuit board shall be capable of operating continuously in the range of –55°C to +45°C.

3 Component selection

1

To the extent practical, all the components used for the PMT HV Base board shall meet the lowest operating temperature of –55(C, as specified by the component manufacturer, where “practical” means that this requirement applies to all resistors, capacitors and diodes; PCB material; conformal coating; and any other components that are readily available for the operating temperature of –55(C or lower.

2

The vendor of the PMT HV Base board shall supply IceCube with a list of components used that do not meet the –55(C or lower operating temperature.

2 3.6.2 Pressure Range

. The PMT HV Base circuit board shall be capable of operating continuously inside the pressure vessel, which will still sustain with the sustained internal pressures of 40,000 Pa to 100,000 Pa.

6 Miscellaneous

1 Conformal coating

Conformal coating is required on both sides of the PCB.

1 Masking requirement

Areas where soldering will be performed after delivery shall be properly masked from the conformal coating.

2 Silkscreen

Silkscreen marking is required on the top side of the PCB.

1 Items to be identified

The said marking shall at least identify the following items:

• Component(s) for setting the first dynode voltage

• Plated-thru holes for PMT connection

• Solderable jumper

• Clean ground wire pad

(Figure 3.7 See PLS Drawing 5549020B_e.pdf)

Figure 3.7 PSL Drawing No. 5549B020. PMT HV Base Board dimensional and component placement requirements. The figure identifies suggested locations for the ribbon cable connector, the coaxial cable attachment, and the clean ground wire attachment. The PCB material thickness is for reference only. (5549020B_e.pdf)

(Figure 3.8 See PLS Drawing 5549021C_e.pdf)

Figure 3.8 PSL Drawing No. 5549C021. PMT HV Base Board component envelope definition. (5549021C_e.pdf)

Appendix 1 Design Notes

-----------------------

3.1.1.2 HV Generation

[i] Justification: Reference to a Cockroft-Walton type generator in the earlier versions of this document has been removed in order to avoid unnecessary constraints on sound technical solutions.

3.1.2 Dynode Chain Voltage Distribution

[ii] Note: The voltage ratios are in accordance with the specification for Hamamatsu PMT Model R7081-02.

3.1.4.1 HV controllability requirements

[iii] Justification: The first dynode voltage mainly controls the peak-to-valley ratio (P/V ratio), whereas the anode voltage mainly controls the gain of the PMT. Once the first dynode voltage is set to a value corresponding to an adequate P/V ratio (greater than 2.2), the voltage should not require readjustment. It is possible to set the first dynode voltage to be sufficiently high so that the P/V ratio always exceeds the minimum required value of 2.2, regardless of the parameter variations among the PMTs. The PMTs under consideration for final selection (Hamamatsu R7081-021, -02) hasve a nominal operating voltage of 460V for the first dynode voltage. The manufacturer of the PMTs, however, confirms that the first dynode voltage may be as high as 800V without adverse effects. See the e-mail exchange between Kael Hanson and Yuji Yoshizawa, Application and Sales Engineer of Hamamatsu Photonics Electron Tube Center. The latest correspondence from Yoshizawa also confirms and guarantees that the cathode-to-anode voltage may be raised to 2000V, rather than previously-stated 1800V, thereby allowing a greater gain adjustment range (i.e., 2000V minus first-dynode voltage).

3.1.4.2 HV monitoring requirement

[iv] Justification: It is useful to be able to read the exact state of the HV. The ADC resolution should meet the DAC resolution.

3.1.4.3 Digital interface

[v] Justification: High-performance ADCs and DACs are readily available with 12-bit resolution. A 12-bit resolution, corresponding to 0.5 volt per bit, is adequate for both monitoring and setting the HVs.

4.2.7.4

3.1.5 Anode Current Sourcing Capability

[vi] Justification: The DC current requirement is obtained by assuming the PMT gain of 5E7, the average number of photoelectrons giving rise to the anode pulse of 1.5, and the noise rate of 1 kHz in deep-ice and 20 kHz at room temperature (worst case). The pulse current requirement is meant to assure the dynamic range supporting all pulses that are realistically possible in the ice. (The Hamamatsu PMT supports up to 70 mA of anode current and we don’t want the PMT Base board to be the bottleneck of any physical measurements.)

3.1.6 Stability

[vii] Justification: The gain-voltage relationship of the PMT is a power law of the form G ~ VB, where B ranges from 8 to 10, depending on the PMT. Assuming the worst case with B=10, a 2% change in gain would require a voltage stability of dV/V = (1/B)(dG/G) = 0.2%, and consequently, a dV of several volt.

3.1.7 Noise

[viii] Justification: The rule of thumb being applied is that the trigger threshold for the system should be about 1/6th of the amplitude of an SPE (5mV), and that the systematic noise should be a small contribution to the triggering at that threshold.

3.2.2.1 Split ground configuration

[ix] Justification: The optimum ground connections for noise immunity need to be determined experimentally in conjunction with the DOM main board. The split ground configuration is prerequisite for noise immunity. The jumper requirement allows flexibility for experimentation.

3.2.3.1.C Primary side requirements

[x] Note: It is vital that the anode signal connection is made with the correct signal polarity.

3.2.3.1.D Secondary side requirements

[xi] Justification: This RG-180B/U cable has a characteristic impedance of 95Wð. The output impedance of the transformer circuit is approximately 100Wð, and theU cable has a characteristic impedance of 95Ω. The output impedance of the transformer circuit is approximately 100Ω, and the output pulse from the anode circuit suffers the least distortion when driving the same impedance.The anode signal requires transformer coupling in order to isolate the anode voltage from the amplifier electronics on the DOM main board. The transformer shall be wound with coax, 19 turns, around a toroidal core. The center conductor of the coax is the primary winding attached to the PMT anode. The coax shield is the secondary winding. Adequate spacing and careful assembly is required to insure high voltage isolation integrity. A 3/8” (9.5 mm) OD plastic plug pressed into the toroid center after winding, holds the turns in place. Alternatively a “belly-band” may be used to hold the turns.

2

3 The coax is RG-178/U or RG-178B/U teflon dielectric with teflon jacket.

4 The core is Magnetics Inc. , Model ZH-42206-TC

5

3.2.3.1.E Coaxial cable installation requirement

[xii] Justification: It is desirable to have the fewest number of solder connections after delivery. The stripping and soldering of the thin coaxial cable is a potential quality issue. Direct soldering is more preferable than using a connector for reliability and cost reasons.and thus, having the PMT HV Base board manufacturer to install the transformer appears to be an attractive approach. (Same is true with the pig-tail coaxial cable for carrying the transformer’s secondary to the DOM main board.)

3.2.4.2 Signal assignment to the PMT mounting holes

[xiii] Note: These connectors have a characteristic impedance of 75Ω.

[xiv] Justification: The pin assignments are consistent with the pinouts for Hamamatsu PMT Models R7081-01 and R7081-02. The plated-thru hole and solder pad dimensions are similar to those for the AMANDA 1999 Tube Base. The PMT supplier (Hamamatsu) has agreed to deliver the PMT with the “No connection” pins cut short or removed.

3.2.5.2 The ribbon cable

[xv] Justification: The 1mm-pitch cable is consistent with a 2mm-pitch ribbon connectors. These connectors are more space-saving than the traditional 2.54mm-pitch counterpart.

3.2.5.6 Digital Board Identification

[xvi] Note: A recommended device for this purpose is a Dallas Semiconductor DS2401.[pic]

Figure 4.5 Split ground configuration requirement

3.3.2 Overall size and shape requirements

[xvii] The terms ice top view and ice bottom view have been defined by PSL for the purpose of defining the OM assembly.

[xviii] Justification: Constraints on the size of the PMT HV Base board arise from the envelope of the Benthos glass sphere; the depth of the PMT placement in the optical gel; the envelope of the PMT itself; and, the position of the sphere penetrator. The mounted height of the PMT HV Base board above the PMT has been chosen to be 20 mm. The drawings provided are intended to make available a generous volume for the PMT HV Base board. The 11-inch PMT has been ruled out due to size constraints in favor of the 10-inch PMT. The 100mm-overall diameter is met by the current Iseg prototype.

3.3.5 Minimum trace spacing requirements

[xix] Justification: These rules are necessary to ensure a reliable high-voltage performance. The rules assume that the conductor traces are on the outer layers of the PCB and that a permanent polymer overcoat (post-assembly conformal coating) is present.

3.3.6 Manual soldering compatibility

[xx] Note: Hamamatsu specifies the soldering conditions as less than 3 sec at 250(C at 10mm from the glass. The PCB may undergo a greater level of heating without exceeding the Hamamatsu spec, since the board is to be mounted 20mm from the PMT glass.

3.4.1 Temperature Range

[xxi] Justification: The ice-top temperature of –52ºC and deep-ice temperature of –40ºC are expected for operation. The higher upper limit for the storage temperature takes care of possible situations during transportation.Temperature outside the above range during transportation and storage is easily avoidable.from +40° C to -70° C.

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