December 4, 2014 Bogdan Wojtsekhowski, APEX

1

Specialized APEX hardware update

Bogdan Wojtsekhowski

December 4, 2014 Bogdan Wojtsekhowski, APEX

2

Specialized APEX hardware: Septa magnet

HRS right

HRS left

.

Positron, P = E0/2

Electron, P = E0/2

Septum

10 high Z thin targets

Beam

.

Septa works well for Δp/p

December 4, 2014 Bogdan Wojtsekhowski, APEX

3

By, Gauss

External shield

Inner shield

5 deg. trajectory passes here

Permendur

Field vs. distance from the beam, ���in the septa middle plane

Specialized APEX hardware: Septa magnet

beam at x =0

trajectories to HRS from 4 to 6 deg.

December 4, 2014 Bogdan Wojtsekhowski, APEX

4

Magnet view and correctors

December 4, 2014 Bogdan Wojtsekhowski, APEX

5

Magnet top view and vacuum connections

SciFi

December 4, 2014 Bogdan Wojtsekhowski, APEX

6

Specialized APEX detector: SciFi detector

Traditional sieve pattern

7"""""""0.000

8"""""""0.271

9"""""""0.524

10"""""""0.784

11"""""""1.037

12"""""""1.309

13"""""""1.559

14"""""""1.825

6""""""-0.238

5""""""-0.510

4""""""-0.760

3""""""-1.032

2""""""-1.282

1""""""-1.538

0""""""-1.788

0""""""0.646

1""""""0.549

5""""""0.000

4""""""0.181

3""""""0.279

2""""""0.365

6"""""-0

.096

7"""""-0

.242

8"""""-0

.481

9"""""-0

.596

10"""""-0

.715

11"""""-0

.830

7"""""""0.000

8"""""""0.259

9"""""""0.522

10"""""""0.778

11"""""""1.044

12"""""""1.306

13"""""""1.556

14"""""""1.819

6""""""-0.253

5""""""-0.519

4""""""-0.775

3""""""-1.031

2""""""-1.288

1""""""-1.544

0""""""-1.803

0""""""0.837

1""""""0.716

5""""""0.095

4""""""0.237

3""""""0.476

2""""""0.599

6""""""0.000

7"""""-0

.235

8"""""-0

.283

9"""""-0

.368

10"""""-0

.555

11"""""-0

.650

Sieve"Hole"Position"Measurement"(inches)

Left%Sieve Right%Sieve

x-plane

z0 50 5 1010 1515 2020

-6-6

-4-4

-2-2

0

2

4

6

8

1010

1212

y-plane

z0 50 5 1010 1515 2020

-4-4

-2-2

0

2

4

6

8

Q1 Q2 Q3DipolDipole

Q1 Q2 DipolDipole Q3

[m]

[m]

[m]

[m]

Tracker

VDCs

Target

Spectrometer optics

Sieve

Calibrated optics is good to 0.1 mrad!

December 4, 2014 Bogdan Wojtsekhowski, APEX

7

Specialized APEX detector: SciFi detector

Active “sieve slit”: a Sci Fiber detector with

1 mm fibers with 1/4” pitch connected via a bundle of 1.5 mm clear fibers to a 64-channel PMT.

Readout via 1877S TDC; 1-3 MHz rate per fiber; off-line time window of < 5 ns

Traditional sieve pattern

Positively

charged particle

optics needs

the SciFi

December 4, 2014 Bogdan Wojtsekhowski, APEX

8

Specialized APEX detector: SciFi detector

Active “sieve slit”: a Sci Fiber detector with

1 mm fibers with 1/4” pitch connected via a bundle of 1.5 mm clear fibers to a 64-channel PMT.

Readout via 1877S TDC; 1-3 MHz rate per fiber; off-line time window of < 5 ns

The front-end is made with the low threshold A/D card from MWDC.

Tested in September – a significant rate of hits

in the DAQ is due to crosstalk signals: capacitive coupling between adjacent electronic channels.

It limits the range of PMT HV and efficiency.

Traditional sieve pattern

December 4, 2014 Bogdan Wojtsekhowski, APEX

9

Specialized APEX detector: SciFi detector

Active “sieve slit”: a Sci Fiber detector with

1 mm fibers with 1/4” pitch connected via a bundle of 1.5 mm clear fibers to a 64-channel PMT.

Readout via costly VME fADC250: 4 ns ticks; allow up to 20 MHz rate per fiber; off-line time window of ~ 5 ns, integration window just 12 ns

December 4, 2014 Bogdan Wojtsekhowski, APEX

10

Specialized APEX detector: SciFi detector

The front-end is a fast NIM amplifier.

Preliminary tested in November – works!

Require more studies with additional

analysis scripts.

December 4, 2014 Bogdan Wojtsekhowski, APEX

11

pixel #

the main pulse in pixel #7

crosstalk in pixel #6

crosstalk in pixel #8

trigger signal

the dinode

16 ns

20 ns

12 ns

8 ns

4 ns

0 ns